1α, 25-Dihydroxyvitamin D3 protects gastric mucosa epithelial cells against Helicobacter pylori-infected apoptosis through a vitamin D receptor-dependent c-Raf/MEK/ERK pathway

CONTEXT

Due to the resistance of Helicobacter pylori to antibiotics, it is difficult to eradicate this pathogenic bacterium from the host. The role of 1α, 25-dihydroxyvitamin D3 (1,25-D3) in H. pylori-infected gastric mucosa epithelial cells remains unknown.

OBJECTIVE

This study investigates the protective property of 1,25-D3 against H. pylori-infected apoptosis in gastric mucosa epithelial cells and its potential molecular mechanisms.

MATERIALS AND METHODS

GES-1 cells were infected with H. pylori SS1 strain (MOI: 100) and treated with 1,25-D3 at 100, 200, and 300 nM for 24 h. Mice were orally gavaged with 10⁸ CFUs of H. pylori and 25 µg/kg 1,25-D3 every other day for 1 month. CCK-8, LDH assay, TUNEL assay and western blot were used to determine the effect of 1,25-D3 on H. pylori-induced apoptosis.

RESULTS

H. pylori infection decreased cell viability to 59.2%, while 100-300 nM 1,25-D3 increased cell viability to 62.2%, 78.4% and 87.1%, respectively. Compared with positive control (4.53-fold), 1,25-D3 reduced caspase-3 activity to 4.49-, 2.88- and 1.49-fold, reduced caspase-6 activity to 2.36-, 1.88- and 1.50-fold, reduced caspase-9 activity to 4.55-, 2.91- and 2.01-fold. 1,25-D3 alters Bcl-2 family, caspase protein expression and c-Raf/MEK/ERK phosphorylation levels in vivo and in vitro. Suppression of 1,25-D3 in apoptosis was reliant on binding to vitamin D receptor. The pharmacological inhibition of c-Raf/MEK/ERK phosphorylation blocked the anti-apoptotic effect of 1,25-D3.

DISCUSSION AND CONCLUSION

1,25-D3 protected gastric mucosa epithelial cells against H. pylori-infected apoptosis through a VDR-dependent c-Raf/MEK/ERK pathway.

Dialysate calcium, alfacalcidol, and clinical outcomes: A post-hoc analysis of the J-DAVID trial

The selection of dialysate calcium concentration (D-Ca) is still controversial among chronic hemodialysis (HD) regimens. We examined the trajectories of CKD MBD parameters among the J-DAVID trial participants to see the effect of D-Ca and alfacalcidol. The trial was an open-label randomized clinical trial including 976 HD patients with intact PTH of 180 pg/mL or lower which compared the users of vitamin D receptor activator (oral alfacalcidol) and non-users over a median of 4 years. The main D-Ca used at baseline were 3.0 mEq/L in 70% and 2.5 mEq/L in 25%, respectively. The primary endpoint was the composite of fatal and non-fatal cardiovascular events and the secondary endpoint was all-cause mortality. Multivariable Cox proportional hazard regression analyses in which D-Ca was included as a possible effect modifier and serum laboratory data as time-varying covariates showed no significant effect modification for composite cardiovascular events or all-cause mortality. This post hoc analysis showed that the effects of alfacalcidol on cardiovascular outcomes were not significantly modified by D-Ca.

Eldecalcitol is superior to alfacalcidol in maintaining bone mineral density in glucocorticoid-induced osteoporosis patients (e-GLORIA)

INTRODUCTION

Eldecalcitol increases bone mineral density (BMD) and reduces vertebral fracture in patients with primary osteoporosis. However, the effect of eldecalcitol on BMD and fracture in glucocorticoid-induced osteoporosis (GIO) patients is unknown. This study was undertaken to compare the effect of eldecalcitol on BMD and fracture with that of alfacalcidol in GIO patients.

MATERIALS AND METHODS

A randomized, open-label, parallel group study was conducted to identify the effectiveness and safety of monotherapy with 0.75 μg eldecalcitol compared with 1.0 μg alfacalcidol in GIO patients.

RESULTS

Lumbar spine BMD increased with eldecalcitol, but decreased with alfacalcidol at 12 and 24 months (between group difference 1.29%, p < 0.01, and 1.10%, p < 0.05, respectively). Total hip and femoral neck BMD were maintained until 24 months by eldecalcitol, but decreased by alfacalcidol (between group difference 0.97%, p < 0.05 and 1.22%, p < 0.05, respectively). Both bone formation and resorption markers were more strongly suppressed by eldecalcitol than by alfacalcidol. Eldecalcitol showed better effect on BMD than alfacalcidol in patients with no prevalent fracture and BMD > 70% of the young adult mean, and with ≤ 3 months of previous glucocorticoid treatment. No significant difference in the incidence of vertebral fracture was found, and the incidence of adverse events was similar between the two groups.

CONCLUSIONS

Eldecalcitol was more effective than alfacalcidol in maintaining BMD in GIO patients. Because eldecalcitol was effective in patients with no or short-term previous glucocorticoid treatment, as well as those without prevalent fracture or low BMD, eldecalcitol can be a good candidate for primary prevention of GIO.

CLINICAL TRIAL REGISTRATION NUMBER

UMIN000011700.

Minodronate combined with alfacalcidol versus alfacalcidol alone for glucocorticoid-induced osteoporosis: a multicenter, randomized, comparative study

INTRODUCTION

This study compared the clinical usefulness of minodronate (50 mg/4 weeks) plus alfacalcidol (1 μg/day) (Group M) with that of alfacalcidol alone (1 μg/day) (Group A) for treating glucocorticoid-induced osteoporosis.

MATERIALS AND METHODS

The primary endpoints were the changes from baseline in lumbar spine (LS) bone mineral density (BMD) and the cumulative incidence of vertebral fracture at 24 months; secondary endpoints included the changes from baseline in total hip (TH) BMD and bone turnover markers.

RESULTS

Of 164 patients enrolled, 152 (Group M, n = 75; Group A, n = 77) were included in the analysis of efficacy. At each time point and at 24 months, LS BMD and TH BMD were significantly higher in Group M than in Group A. The 152 patients were divided into two subgroups that were previously treated with glucocorticoids for ≤ 3 months or > 3 months. In both subgroups, the changes from baseline in LS BMD and TH BMD from baseline at 24 months had increased more in Group M than in Group A. There were no differences found in the incidence of vertebral fracture between the groups, because the number of enrolled patients was lesser than that initially expected. In Group M, both bone formation and resorption markers significantly decreased from baseline at 3 months and maintained at 6, 12, and 24 months.

CONCLUSIONS

Minodronate plus alfacalcidol was more effective than alfacalcidol alone in increasing BMD and was effective in increasing BMD for both prevention and treatment. Therefore, minodronate can be a good candidate drug for the treatment of glucocorticoid-induced osteoporosis.

Co-targeting of endothelin-A and vitamin D receptors: a novel strategy to ameliorate cisplatin-induced nephrotoxicity

BACKGROUND

Although modulation of the vitamin D receptor (VDR) and endothelin-A receptor (ETAR) has previously been reported to offer renoprotection against cisplatin-induced nephrotoxicity, the possible interaction between the ET-1 and vitamin D pathways remains obscure. Therefore, the present study addressed the possible interaction between these signalling pathways using BQ-123 (a selective ETAR blocker) and alfacalcidol (a vitamin D3 analogue) separately or in combination.

METHODS

Male Sprague-Dawley rats were divided into the following groups: control (DMSO orally), cisplatin (single dose of 6 mg/kg ip; nephrotoxicity model), cisplatin + BQ-123 (1 mg/kg BQ-123 ip 1 h before and 1 day after cisplatin), cisplatin + alfacalcidol (50 ng/kg alfacalcidol orally 5 days before and 14 days after cisplatin), and cisplatin + BQ-123+alfacalcidol. Nephrotoxicity was evaluated 96 h and 14 days following cisplatin administration.

RESULTS

Both BQ-123 and alfacalcidol counteracted cisplatin-induced nephrotoxic changes. Specifically, they reduced serum creatinine and urea levels; renal tumour necrosis factor-alpha (TNF-α), transforming growth factor-beta1 (TGF-β1), and phosphorylated nuclear factor-kappa B (pNF-κB) content; and caspase-3 activity. They downregulated ET-1 and ETAR expression and ameliorated cisplatin-induced acute tubular necrosis. In addition, the treatments have increased VDR and endothelin-B receptor (ETBR) expression; however, BQ-123 did not affect ETBR. The effect of the combination regimen surpassed that of each drug alone.

CONCLUSION

These findings highlight the potential cross-talk between vitamin D and ET-1 pathways and pave the way for future preclinical/clinical studies to explore further mechanisms involved in this cross-talk.

Effect of Oral Alfacalcidol on Clinical Outcomes in Patients Without Secondary Hyperparathyroidism Receiving Maintenance Hemodialysis: The J-DAVID Randomized Clinical Trial

IMPORTANCE

Patients with chronic kidney disease have impaired vitamin D activation and elevated cardiovascular risk. Observational studies in patients treated with hemodialysis showed that the use of active vitamin D sterols was associated with lower risk of all-cause mortality, regardless of parathyroid hormone levels.

OBJECTIVE

To determine whether vitamin D receptor activators reduce cardiovascular events and mortality in patients without secondary hyperparathyroidism undergoing hemodialysis.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, open-label, blinded end point multicenter study of 1289 patients in 207 dialysis centers in Japan. The study included 976 patients receiving maintenance hemodialysis with serum intact parathyroid hormone levels less than or equal to 180 pg/mL. The first and last participants were enrolled on August 18, 2008, and January 26, 2011, respectively. The final date of follow-up was April 4, 2015.

INTERVENTIONS

Treatment with 0.5 μg of oral alfacalcidol per day (intervention group; n = 495) vs treatment without vitamin D receptor activators (control group; n = 481).

MAIN OUTCOMES AND MEASURES

The primary outcome was a composite measure of fatal and nonfatal cardiovascular events, including myocardial infarctions, hospitalizations for congestive heart failure, stroke, aortic dissection/rupture, amputation of lower limb due to ischemia, and cardiac sudden death; coronary revascularization; and leg artery revascularization during 48 months of follow-up. The secondary outcome was all-cause death.

RESULTS

Among 976 patients who were randomized from 108 dialysis centers, 964 patients were included in the intention-to-treat analysis (median age, 65 years; 386 women [40.0%]), and 944 (97.9%) completed the trial. During follow-up (median, 4.0 years), the primary composite outcome of cardiovascular events occurred in 103 of 488 patients (21.1%) in the intervention group and 85 of 476 patients (17.9%) in the control group (absolute difference, 3.25% [95% CI, -1.75% to 8.24%]; hazard ratio, 1.25 [95% CI, 0.94-1.67]; P = .13). There was no significant difference in the secondary outcome of all-cause mortality between the groups (18.2% vs 16.8%, respectively; hazard ratio, 1.12 [95% CI, 0.83-1.52]; P = .46). Of the 488 participants in the intervention group, 199 (40.8%) experienced serious adverse events that were classified as cardiovascular, 64 (13.1%) experienced adverse events classified as infection, and 22 (4.5%) experienced malignancy-related serious adverse events. Of 476 participants in the control group, 191 (40.1%) experienced cardiovascular-related serious adverse events, 63 (13.2%) experienced infection-related serious adverse events, and 21 (4.4%) experienced malignancy-related adverse events.

CONCLUSIONS AND RELEVANCE

Among patients without secondary hyperparathyroidism undergoing maintenance hemodialysis, oral alfacalcidol compared with usual care did not reduce the risk of a composite measure of select cardiovascular events. These findings do not support the use of vitamin D receptor activators for patients such as these.

TRIAL REGISTRATION

UMIN-CTR Identifier: UMIN000001194.

Effects of activated vitamin D, alfacalcidol, and low-intensity aerobic exercise on osteopenia and muscle atrophy in type 2 diabetes mellitus model rats

Diabetes mellitus causes secondary osteoporosis and muscle atrophy. The ability of alfacalcidol (ALF) and exercise (Exe) to inhibit osteoporosis and muscle atrophy in type 2 diabetes mellitus (T2DM) model rats was examined. Twenty-week-old Otsuka Long-Evans Tokushima Fatty rats were randomized to ALF (orally 0.1 μg/kg/day), Exe (treadmill exercise at 10 m/min, 60 min/day, 5 days/week), Comb (ALF and Exe), and Cont (T2DM control treated with vehicle and no exercise) groups (n = 8–10 per group). Sedentary Long-Evans Tokushima Otsuka rats were used as a non-hyperphagic control. After treatment for 2 or 6 weeks, blood glucose (BG) levels, cross-sectional area (CSA) of tibialis anterior muscle fibers, femoral bone mineral density (BMD), and relative quantities of muscle anabolic markers (Pax7, MyoD, and myogenin) and catabolic markers (Atrogin-1, MuRF1, and REDD1) of the soleus muscle assessed by real-time polymerase chain reaction assays were measured. Exe and Comb treatments for 6 weeks decreased BG levels compared with those of the Cont group. ALF, Exe, and Comb treatments for 2 and 6 weeks recovered the CSA compared with that of the Cont group. ALF and Comb treatments for 6 weeks increased femoral BMDs compared with those of the Cont group. After 2 weeks of treatment, Comb treatment increased MyoD expression and decreased MuRF1 expression. ALF or Exe monotherapy significantly decreased Atrogin-1 or MuRF1 expression after 2 weeks of treatment, respectively. After 6 weeks of treatment, ALF and Comb treatments decreased Atrogin-1 and REDD1. These results demonstrate that a combination of ALF and Exe improved CSA from the early phase of treatment by stimulating skeletal muscle differentiation and suppressing muscle catabolic genes. Improvements in BG, BMD, and CSA were observed as long-term effects of the combination therapy. Continued suppression of muscle catabolic genes was observed as a background to these effects.

Eldecalcitol is more effective in promoting osteogenesis than alfacalcidol in Cyp27b1-knockout mice

Calcium (Ca) absorption from the intestinal tract is promoted by active vitamin D (1α,25D3). Vitamin D not only promotes Ca homeostasis, but it also inhibits bone resorption and promotes osteogenesis, thus playing a role in the maintenance of normal bone metabolism. Because 1α,25D3 plays an important role in osteogenesis, vitamin D formulations, such as alfacalcidol (ALF) and eldecalcitol (ELD), are used for treating osteoporosis. While it is known that, in contrast to ALF, ELD is an active ligand that directly acts on bone, the reason for its superior osteogenesis effects is unknown. Cyp27b1-knockout mice (Cyp27b1-/-mice) are congenitally deficient in 1α,25D3 and exhibit marked hypocalcemia and high parathyroid hormone levels, resulting in osteodystrophy involving bone hypocalcification and growth plate cartilage hypertrophy. However, because the vitamin D receptor is expressed normally in Cyp27b1-/-mice, they respond normally to 1α,25D3. Accordingly, in Cyp27b1-/-mice, the pharmacological effects of exogenously administered active vitamin D derivatives can be analyzed without being affected by 1α,25D3. We used Cyp27b1-/-mice to characterize and clarify the superior osteogenic effects of ELD on the bone in comparison with ALF. The results indicated that compared to ALF, ELD strongly induces ECaC2, calbindin-D9k, and CYP24A1 in the duodenum, promoting Ca absorption and decreasing the plasma concentration of 1α,25D3, resulting in improved osteogenesis. Because bone morphological measurements demonstrated that ELD has stronger effects on bone calcification, trabecular formation, and cancellous bone density than ALF, ELD appears to be a more effective therapeutic agent for treating postmenopausal osteoporosis, in which cancellous bone density decreases markedly. By using Cyp27b1-/-mice, this study was the first to succeed in clarifying the osteogenic effect of ELD without any influence of endogenous 1α,25D3. Furthermore, ELD more strongly enhanced bone mineralization, trabecular proliferation, and cancellous bone density than did ALF. Thus, ELD is expected to show an effect on postmenopausal osteoporosis, in which cancellous bone mineral density decreases markedly. In the future, this study may enable the development of next-generation active vitamin D derivatives with higher affinity for bone than ELD.

Effect of combined vitamin D receptor activator and lanthanum carbonate on serum fibroblast growth factor 23 level in predialysis patients (CVD-LAF study): design and method

BACKGROUND

Whether vitamin D receptor activator (VDRA) use is beneficial in chronic kidney disease (CKD) is unclear, because it is possible that VDRA increases serum fibroblast growth factor 23 (FGF23) levels. We will conduct a randomized controlled trial in predialysis patients to determine the effect of VDRA alone or in combination with lanthanum carbonate (LC) on serum FGF23 levels.

METHODS

This is a single-center, open-label, randomized controlled trial. Enrollment will commence February 1, 2018, using the following inclusion criteria: (1) age ≥ 20 years, (2) CKD with an estimated glomerular filtration rate of 10-45 mL/min/1.73 m², (3) serum adjusted calcium level < 9.5 mg/dL, (4) serum phosphate level 4.0-6.0 mg/dL, and (5) serum intact parathyroid hormone (PTH) level ≥ 60 pg/mL. Study patients will be randomized 1:1 to receive alfacalcidol alone or in combination with LC. The initial dose of alfacalcidol will be 0.25-0.5 µg once a day according to serum adjusted calcium level. The initial dose of LC will be 250 mg once a day. We will measure serum intact and C-terminal FGF23 at 0, 4, 8, 12, 24, and 52 weeks. The primary outcome will be serum FGF23 level at 24 weeks compared with baseline.

DISCUSSION

This study aims to determine whether low-dose oral VDRA increases serum FGF23 level and whether the combination of VDRA and LC inhibits this increase. The results will be useful in the management of CKD-mineral and bone disorder in predialysis patients.

TRIAL REGISTRATION

UMIN000030503. Registered 20 January 2018.

Stimulation of intestinal calcium absorption by orally administrated vitamin D3 compounds: a prospective open-label randomized trial in osteoporosis

Intestinal fractional calcium absorption (FCA) was assessed before and after vitamin D3 treatment. Serum 1,25(OH)2D concentration was significantly increased by plain vitamin D3 and reduced by eldecalcitol. The 1α hydroxyl calcidiol and eldecalcitol treatments increased FCA, which may be induced through direct stimulation of vitamin D receptors in the intestine.

INTRODUCTION

To assess the effects of vitamin D3 compounds on intestinal FCA and calcium-regulating hormones in post-menopausal osteoporosis, a randomized open-label prospective study was conducted.

METHODS

Forty eligible patients were allocated randomly into four groups: eldecalcitol (ELD; 0.75 μg/day), 1α hydroxyl calcidiol (ALF; 1 μg/day), plain vitamin D3 (800 IU/day), and control. Before and after the 4-week treatment, intestinal FCA was estimated by using a double isotope method, and serum concentrations of calcium-regulating hormones and a bone turnover marker were measured.

RESULTS

The baseline FCA value of the participants was 21.5 ± 7.9% (mean ± SD) and was significantly correlated with serum 1,25(OH)2D (calcitriol) concentration. After the treatment, the FCA significantly increased by 59.5% (95% CI, 41.6 to 77.4%) in the ELD group and by 45.9% (27.9 to 63.8%) in the ALF group, whereas no significant change in the plain vitamin D3 group was found. Unlike the baseline FCA, post-treatment FCA exhibited no significant correlation with serum calcitriol concentration. Parathyroid hormone levels were suppressed by ALF and plain vitamin D3 but were sustained in the ELD and control groups. Serum calcitriol tended to be suppressed by ELD, whereas plain vitamin D3 treatment increased both serum 25(OH)D and calcitriol concentrations.

CONCLUSION

These findings suggest that oral administration of vitamin D3 analogues (ALF and ELD) stimulates FCA but plain vitamin D3 does not. Those effects of vitamin D3 compounds on FCA were independent of serum calcitriol concentration, suggesting that ALF and ELD may directly stimulate intestinal vitamin D receptors.

Effects of alendronate and alfacalcidol on bone in patients with myasthenia gravis initiating glucocorticoids treatment

OBJECTIVE

Glucocorticoids (GCs) are the first-line treatment for myasthenia gravis (MG) and act as long-term immunosuppressants. However, GCs can induce osteoporosis and bone fractures. In this study, we evaluate the effects of oral alendronate and alfacalcidol, or alfacalcidol alone on the bone of Chinese patients with MG who will initiate treatment with GCs.

DESIGN AND METHODS

A total of 75 patients were included in this 12-month prospective, open-label, single-centre study. Patients with bone mineral density (BMD) T-score less than -1.0 at baseline were treated with 70 mg of alendronate per week. Patients with BMD T-score greater than -1.0 at baseline were included in the alfacalcidol-alone group. Patients in two groups were treated with 0.25 μg of alfacalcidol every other day and 600 mg of calcium daily.

RESULTS

After 12 months of treatment, the mean BMD of lumbar spine, femoral neck and total hip increased by 3.4% (P = .002), 1.8% (P = .21) and 2.6% (P = .02), respectively, in alendronate group. In alfacalcidol-alone group, the mean BMD of lumbar spine, femoral neck and total hip decreased by 6.1%, 3.2% and 3.3%, respectively (all P < .001 vs baseline).

CONCLUSIONS

We demonstrated for the first time that treatment with alendronate combined with alfacalcidol significantly increased BMD, decreased bone turnover biomarker levels and reduced the occurrence of hypercalciuria in a large cohort of Chinese patients with MG who initiated treatment with glucocorticoids. However, treatment with alfacalcidol alone failed to prevent bone loss in patients with MG receiving glucocorticoid therapy.

Endogenously produced nonclassical vitamin D hydroxy-metabolites act as "biased" agonists on VDR and inverse agonists on RORα and RORγ

The classical pathway of vitamin D activation follows the sequence D3→25(OH)D3→1,25(OH)₂D3 with the final product acting on the receptor for vitamin D (VDR). An alternative pathway can be started by the action of CYP11A1 on the side chain of D3, primarily producing 20(OH)D3, 22(OH)D3, 20,23(OH)₂D3, 20,22(OH)₂D3 and 17,20,23(OH)₃D3. Some of these metabolites are hydroxylated by CYP27B1 at C1α, by CYP24A1 at C24 and C25, and by CYP27A1 at C25 and C26. The products of these pathways are biologically active. In the epidermis and/or serum or adrenals we detected 20(OH)D3, 22(OH)D3, 20,22(OH)₂D3, 20,23(OH)₂D3, 17,20,23(OH)₃D3, 1,20(OH)₂D3, 1,20,23(OH)₃D3, 1,20,22(OH)₃D3, 20,24(OH)₂D3, 1,20,24(OH)₃D3, 20,25(OH)₂D3, 1,20,25(OH)₃D3, 20,26(OH)₂D3 and 1,20,26(OH)₃D3. 20(OH)D3 and 20,23(OH)₂D3 are non-calcemic, while the addition of an OH at C1α confers some calcemic activity. Molecular modeling and functional assays show that the major products of the pathway can act as "biased" agonists for the VDR with high docking scores to the ligand binding domain (LBD), but lower than that of 1,25(OH)₂D3. Importantly, cell based functional receptor studies and molecular modeling have identified the novel secosteroids as inverse agonists of both RORα and RORγ receptors. Specifically, they have high docking scores using crystal structures of RORα and RORγ LBDs. Furthermore, 20(OH)D3 and 20,23(OH)₂D3 have been tested in a cell model that expresses a Tet-on RORα or RORγ vector and a RORE-LUC reporter (ROR-responsive element), and in a mammalian 2-hybrid model that test interactions between an LBD-interacting LXXLL-peptide and the LBD of RORα/γ. These assays demonstrated that the novel secosteroids have ROR-antagonist activities that were further confirmed by the inhibition of IL17 promoter activity in cells overexpressing RORα/γ. In conclusion, endogenously produced novel D3 hydroxy-derivatives can act both as "biased" agonists of the VDR and/or inverse agonists of RORα/γ. We suggest that the identification of large number of endogenously produced alternative hydroxy-metabolites of D3 that are biologically active, and of possible alternative receptors, may offer an explanation for the pleiotropic and diverse activities of vitamin D, previously assigned solely to 1,25(OH)₂D3 and VDR.

The effect of alfacalcidiol and metformin on metabolic disturbances in women with polycystic ovary syndrome

BACKGROUND

The aim of this randomized clinical trial (RCT) was to evaluate the effect of vitamin D supplementation in obese, insulin-resistant (IR) and vitamin D-deficient polycystic ovary syndrome (PCOS) women on metabolic abnormalities in comparison to the effect of metformin or combined metformin plus vitamin D therapy.

MATERIAL AND METHODS

Thirty-nine PCOS women who fulfilled the inclusion criteria were randomized into three groups and treated with alfacalcidiol, combined alfacalcidiol and metformin therapy and metformin for 6 months. Body weight, body mass index (BMI), waist circumference, total body fat and fat distribution were measured before and after 6 months of treatment. Plasma fasting glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR) and lipid profiles were measured at the same time.

RESULTS

There was a significant decrease in body weight, BMI, waist circumference, total body fat and serum glucose levels in the metformin group (p<0.05), whereas PCOS women treated with alfacalcidiol did not significantly change their anthropometric and metabolic parameters. A significant decrease in waist circumference (p<0.05) in the group treated with metformin and alfacalcidiol was detected without other significant metabolic changes (all p>0.05). There were no significant changes in metabolic parameters (p>0.05) after vitamin D therapy except for a slight but non-significant trend towards higher high-density lipoprotein (HDL) cholesterol levels (p=0.087).

CONCLUSION

We conclude that vitamin D supplementation has no significant effect on anthropometric and metabolic parameters in PCOS women. Metformin has been still the most effective modality for the treatment of metabolic changes in PCOS.

Free 25(OH)D and Calcium Absorption, PTH, and Markers of Bone Turnover

CONTEXT

It has been proposed that serum free 25-hydroxyvitamin D [25(OH)D] may better reflect vitamin D action than total 25(OH)D. An ELISA for serum free 25(OH)D has recently become available, permitting direct assay.

OBJECTIVE

To determine whether serum free 25(OH)D provides additional information in relation to calcium absorption and other biomarkers of vitamin D action compared to total serum 25(OH)D.

SETTING

Ambulatory research setting in a teaching hospital.

OUTCOME

Serum free 25(OH)D measured in a previously performed study of varied doses of vitamin D3 (placebo and 800, 2000, and 4000 IU) on calcium absorption, PTH, procollagen type 1 N-terminal propeptide, and C-terminal telopeptides of type I collagen. Free 25(OH)D was measured by ELISA. Calcium absorption was measured at baseline and at 10 weeks using stable dual calcium isotopes.

RESULTS

Seventy-one subjects completed this randomized, placebo-controlled trial. Baseline group mean free and total 25(OH)D varied from 4.7 ± 1.8 to 5.4 ± 1.5 pg/mL, and from 23.7 ± 5.9 to 25.9 ± 6.1 ng/mL, respectively. Participants assigned to the 4000-IU dose arm achieved free 25(OH)D levels of 10.4 pg/mL and total 25(OH)D levels of 40.4 ng/mL. Total and free 25(OH)D were highly correlated at baseline and after increasing vitamin D dosing (r = 0.80 and 0.85, respectively). Free 25(OH)D closely reflected changes in total 25(OH)D. PTH was similarly correlated at baseline and follow-up with total and free 25(OH)D. Serum C-terminal telopeptides of type I collagen had a moderate positive correlation with total and free 25(OH)D at follow-up. The serum 1,25-dihydroxyvitamin D change increased significantly with the change in 25(OH)D but not with the change in free 25(OH)D.

CONCLUSION

There was no advantage from measuring free over total 25(OH)D in assessing the response of calcium absorption, PTH, and markers of bone turnover to vitamin D. Free 25(OH)D responded to increasing doses of vitamin D in a similar fashion to total 25(OH)D.

[Bone Cell Biology Assessed by Microscopic Approach. The effects of active vitamin D3 such as alfacalcidol and eldecalcitol on bone quality]

Active vitamin D3 is used for the treatment for osteoporosis in Japan. Recently, data have accumulated that collagen cross-link formation in bone affect bone strength. In fact, impaired enzymatic cross-linking, over-hydroxylation of crosslinks, and an increase in non-enzymatic crosslinking advanced glycation end products (AGEs) such as pentosidine, in bone collagen have been proposed as a major cause of bone fragility in osteoporosis. We reported that alfacalcidol and eldecalcitol improves bone material properties such as collagen cross-link formation, microarchitecture, and microcrack resulting in the increase of bone strength (Saito M, Bone 2010;46:1170-1179, Calcif Tissue Int 2011;88:314-324, Bone, 2015;73:8-15). In this review, we described how active vitamin D3 improve bone collagen cross-link formation and mineral qualities.

Effect of 1,25-dihydroxycholecalciferol on the duodenal villi and alkaline phosphatase in the developing chick embryo

Administration of 1,25-(OH)2D3 to developing 14-day chick embryo gave precocious induction of alkaline phosphatase in 20-day chick embryonic duodenum. 1,25-(OH)-2D3-induced alkaline phosphase involved in changes in Km and Vmax values. Furthermore, polyacrylamide gel disc electrophoresis of n-butanol-solubilized alkaline phosphatase from control and 1,25-(OH)2D3-treated chick embryonic duodenum revealed that 1,25-(OH)2D3 involved the transformation of neuraminidase-resistant fast migrating form to the neuraminidase-sensitive faster migrating one. Scanning electron microscopic data showed that the injection of 1,25-(OH)2D3 stimulated the elongation of duodenal microvilli, although there was no effect on the duodenal absorptive epithelial cell height.

Vitamin D and parathyroid hormone degradation by the kidney

Parathyroid function is controlled by the regulation of hormone secretion as well as degradation, through the action of calcium and vitamin D derivatives. In order to clarify the relationship between vitamin D metabolism and parathyroid degradation system, parathyroid hormone (PTH)-degrading activities of the kidney were measured in vitamin D repleted and depleted rats given various derivatives of vitamin D. Kidney calcium content rose markedly in animals given 10 microgram/kg 1 alpha(OH) vitamin D3 and 1,000 microgram/kg dihydrotachysterol and PTH-degrading activity rose only in these animals, indicating a parallelism between kidney calcium content and PTH-degrading activity of the kidney tissue. These vitamin D derivatives also increased the PTH-degrading activity of kidney tissue when they were added in vitro.

Effect of 1 alpha-hydroxycholecalciferol on the skeletal mineral metabolism and bone morphogenesis

Administered 1 alpha-OH-D3 is hydrolyzed in liver and then converted to active 1 alpha, 25-(OH)2-D3. An increased serum calcium content was observed in rats administered 1 alpha-OH-D3. No calcium and magnesium increase was noticed in cortical bone due to 1 alpha-OH-D3 administration. Morphogenesis of bone and cartilage in implanted bone matrix in a group of 1 alpha-OH-D3 administered host rats seemed relatively increased to a slight extent.

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 2β-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'.

[Osteoporosis correction in experiment]

Osteoporosis is simulated in rats by chronic administration of omeprazole or serotonin for 6 months; investigated bone status in the model of liver fibrosis and the administration of serotonin against liver fibrosis. The following experimental groups of rats: with bilateral ovariectomy, with bilateral ovariectomy and administration of omeprazole, with the introduction of serotonin, with serotonin administration and bilateral ovariectomy, with model of liver fibrosis, with liver fibrosis model and administration of serotonin were used. The content of Ca, P, alkaline phosphatase, albumin, serum creatinine, and the content of Ca, P, Mg andFe in the bone was determined. It was found that the administration of mesenchymal stromal cells reduces the severity of osteoporosis. The effects of alfacalcidol on experimental osteoporosis was investigated. Introduction of alfacalcidol in all experimental groups increased the bone formation.

[Experience with active vitamin D metabolites in phosphorus-calcium metabolic disorders in patients with predialysis chronic kidney disease]

AIM

To evaluate the efficacy and safety of alfacalcidol and paracalcitol used to correct impaired phosphorus-calcium metabolism (PCM) in patients with predialysis chronic kidney disease (CKD).

SUBJECTS AND METHODS

Examinations were made in 128 patients with Stages III-V CKD, including 89 (69.5%) patients with chronic glomerulonephritis, 30 (23.4%) with chronic tubulointerstitial nephritis, and 9 (7.1%) with hypertensive nephrosclerosis. Impaired PCM was detected in 90 (70.3%) of the examined patients. According to the pattern of the previous therapy, all the 90 CKD patients with PCM disorders were divided into 3 groups: 1) 32 patients with Stages IIIB-V CKD who had taken oral alfacalcidol 0.25 microg/day; 2) 28 patients with Stages IIIB-V CKD who had used oral paricalcitol 1 microg/day; 3) 30 patients with Stages IIIB-V CKD who had not received, as self- motivated, active vitamin D metabolites at the predialysis stage.

RESULTS

Alfacalcidol and paricalcitol were quite satisfactorily tolerated by the patients. After 3 months of initiation of the use of these agents, Groups 1 and 2 patients with predialysis CKD and baseline elevated blood intact parathyroid hormone (iPTH) levels could not only achieve, but also maintain target blood iPTH levels. In the patients taking paricalcitol, the urinary protein level decreased more promptly; moreover, by the end of month 6 the reduction in blood pressure (BP) was more significant than in those using alfacalcidol (p < 0.05). Comparison of the effects of angiotensin-converting enzyme inhibitors in combination with alfacalcidol or paricalcitol on BP changes and left ventricular mass index indicated that the most pronounced positive changes occurred when angiotensin-converting enzyme inhibitors were used in combination with paricalcitol.

CONCLUSION

The use of paricalcitol in predialysis CKD with PTH hyperproduction results in not only normalization of the levels of both PTH and osseous isoenzyme of alkaline phosphatase, but also in significantly reduced daily proteinuria and regression of left ventricular hypertrophy and chronic heart failure.

Enhanced transcription of pancreatic peptide YY by 1α-hydroxyvitamin D3 administration in streptozotocin-induced diabetic mice

Peptide YY (PYY) is a peptide hormone secreted from L cells in the intestine in response to food intake that regulates appetite and gastrointestinal function. PYY is also produced in the pancreatic islets. The vitamin D receptor (VDR) is a nuclear receptor for the active form of vitamin D3 that regulates numerous physiological processes. VDR is expressed in the pancreatic islets and pharmacological VDR activation increases PYY expression in mouse peripheral islet cells. Although VDR is present in insulin-producing β cells as well as non-β cells, the role of β cell VDR in Pyy transcription remains unknown. We treated mice with streptozotocin to ablate β cells in the pancreas. Pancreatic Vdr mRNA expression was decreased in streptozotocin-induced diabetic mice. Interestingly, streptozotocin-treated mice exhibited increased basal Pyy expression and 1α-hydroxyvitamin D3 treatment further increased expression. Moreover, 1α-hydroxyvitamin D3 increased mRNA expression of pancreatic polypeptide and decreased that of neuropeptide Y in streptozotocin-induced diabetic mice but not in control mice. 1α-Hydroxyvitamin D3 slightly increased mRNA expression of insulin but transcript levels were nearly undetectable in the pancreas of streptozotocin-treated mice. Thus, VDR in non-β islet cells is involved in Pyy expression in the mouse pancreas. The findings from this β cell ablation study suggest a hormone transcription regulatory network composed of β cells and non-β cells.

Effects of combined treatment with eldecalcitol and alendronate on bone mass, mechanical properties, and bone histomorphometry in ovariectomized rats: a comparison with alfacalcidol and alendronate

Eldecalcitol (ELD), a 2β-hydroxypropyloxy derivative of 1α,25 (OH) 2D3, inhibits bone resorption more potently than alfacalcidol (ALF) while maintaining osteoblastic function in an ovariectomized (OVX) osteoporosis rat model. Alendronate (ALN), which is the most common bisphosphonate used for the treatment of osteoporosis, increases the bone mineral density (BMD) by suppressing bone resorption. In this study, we investigated the effects of combination treatments with ELD and ALN or with ALF and ALN on bone mass and strength in OVX rats. Seventy female rats, 32 weeks old, were assigned to seven groups: (1) a sham-operated control group; (2) an OVX-control group; (3) an ELD group; (4) an ALF group; (5) an ALN group; (6) an ELD+ALN group; and (7) an ALF+ALN group. OVX rats were orally treated with ELD (0.015 μg/kg), ALF (0.0375 μg/kg), or ALN (0.2mg/kg) daily for 12 weeks. In both the lumbar spine and the femur, ELD and ALF monotherapy significantly increased the BMD, and ELD+ALN and ALF+ALN significantly increased the BMD, compared with ALN monotherapy, as an additive effect. In particular, ELD+ALN resulted in a significantly higher BMD than ALF+ALN in the femur. On mechanical testing of the lumbar spine, ELD and ALF monotherapy significantly increased the ultimate load, and ELD+ALN and ALF+ALN significantly increased the ultimate load compared with ALN monotherapy. In the femur, ELD, ELD+ALN, and ALF+ALN treatment significantly increased the ultimate load, compared with the OVX-control group, and ELD+ALN resulted in a significantly higher ultimate load than ALN monotherapy. A histomorphometric analysis showed that ELD monotherapy and ELD+ALN combination therapy had a potent inhibitory effect on bone resorption parameters (osteoclast surface and eroded surface), while maintaining bone formation parameters (osteoblast surface and osteoid surface). By contrast, ALF and ALF+ALN significantly lowered the histological parameters of both bone resorption and formation. These results suggested that ELD or ALF used in combination with ALN has therapeutic advantages over ALN monotherapy, with ELD+ALN combination treatment producing an especially beneficial anti-osteoporotic effect by inhibiting osteoclastic bone resorption and maintaining osteoblastic function, compared with ALF+ALN combination treatment.

Vitamin D receptor activation induces peptide YY transcription in pancreatic islets

Peptide YY (PYY) is a peptide hormone secreted from L cells in the intestine after food intake and regulates appetite and intestinal function. PYY is also expressed in the pancreas, but the mechanisms of regulation of pancreatic PYY expression have not been elucidated. The vitamin D receptor (VDR) is a nuclear receptor for the active form of vitamin D(3) and regulates numerous physiological processes. Because VDR is expressed in the pancreas, we investigated the role of pancreatic VDR activation and found that Pyy is a VDR target gene in the mouse pancreas. Treatment of mice with 1α-hydroxyvitamin D(3) increased plasma PYY levels. VDR activation increased mRNA and protein expression of PYY in the pancreatic islets of mice and pancreatic endocrine cell lines but did not change intestinal PYY expression. 1α-Hydroxyvitamin D(3)-dependent induction of pancreatic and plasma PYY was abolished in VDR-null mice. We identified a functional vitamin D-responsive element in the mouse Pyy promoter using chromatin immunoprecipitation assay, EMSA, and luciferase promoter assay. Thus, Pyy is a tissue-specific VDR target gene. The pancreatic VDR-PYY pathway may mediate a regulatory function of vitamin D in the neuroendocrine system.

Alfacalcidol-supplemented raloxifene therapy has greater bone-sparing effect than raloxifene-alone therapy in postmenopausal Japanese women with osteoporosis or osteopenia

Vitamin D insufficiency is prevalent in osteopenic and osteoporotic postmenopausal women. The persistent increase in circulating parathyroid hormone (PTH) caused by vitamin D insufficiency reduces bone density response to antiresorptive agents in these postmenopausal women. It is not well known whether administration of raloxifene might increase serum PTH secondary to the suppression of serum calcium in postmenopausal women with osteopenia or osteoporosis. We tried to assess whether raloxifene might affect serum PTH and whether the addition of alfacalcidol to raloxifene therapy could have favorable effects on bone mineral density (BMD) and bone turnover as compared to raloxifene-alone therapy in postmenopausal Japanese women with osteoporosis or osteopenia (≤2.0 SD based on young Japanese women). A total of 169 subjects were randomly assigned to groups receiving 60 mg raloxifene (R), or 1 μg alfacalcidol (D), or a combination of both (R + D) for 2 years. Serum levels of 25-hydroxyvitamin D [25(OH)D] were measured at randomization. The modified 'intention to treat' method was used. We compared the groups using a Tukey-Kramer test for changes in L- and TH-BMD and calcium metabolism when significant differences were found using one-way ANOVA. The parameters in each group during the experimental period were analyzed by means of paired t tests. Baseline 25(OH)D and i-PTH were 23.7 ng/ml and 38.4 pg/ml, respectively. At 6 months, i-PTH demonstrated a significant increase (+21.0%) in the R-group whereas significant decreases in i-PTH were observed in the D-group and combination-group (-15.9 and -8.9%, respectively). There were significant increases in L-BMD in the R + D-group (+4.1% at 1 year and +4.7% at 2 years, P < 0.0001) and in the R-group (+2.9% at 1 year and +2.8% at 2 years, P < 0.001), but the difference between the groups did not reach a significant level. Vitamin D status at randomization did not affect the subsequent BMD response in coadministration of alfacalcidol with raloxifene. Supplementation with alfacalcidol to raloxifene therapy demonstrates a greater bone-sparing effect by suppressing the secondary increment of serum PTH than when raloxifene is used alone.

C15-functionalized 16-ene-1α,25-dihydroxyvitamin D3 is a new vitamin D analog with unique biological properties

The Δ(16) structure as a vitamin D analog enhanced vitamin D receptor (VDR) binding affinity and induced significant cell differentiation, whereas its relative calcemic activity was reduced compared to 1α,25-dihydroxyvitamin D(3) (1α,25(OH)(2)D(3)). Methodologies available to introduce a double bond at C16-C17 of the D-ring on the seco-steroidal skeleton were limited; therefore, a new synthetic strategy was developed to obtain not only the Δ(16) structure, but also a new C15-functional group. Since C15-functionalization was unprecedented in vitamin D analog studies, the hybrid structure of Δ(16) and the C15-OH group at the D-ring may provide important information on the structure-activity relationship with vitamin D analogs. The synthesized 16-ene-2α-methyl-1α,15α,25-trihydroxyvitamin D(3) showed almost 3-times higher VDR binding affinity and an equipotent level of osteocalcin promoter transactivation activity in human osteosarcoma cells as compared to 1α,25(OH)(2)D(3).

Effects of alfacalcidol on circulating cytokines and growth factors in rat skeletal muscle

Supra-physiological levels of vitamin D induce skeletal muscle atrophy, which may be particularly detrimental in already sarcopaenic elderly. Neither the cause nor whether the atrophy is fibre type specific are known. To obtain supraphysiological levels of circulating vitamin D (1,25(OH)(2)D(3)) 27.5-month-old female Fischer(344) × Brown Norway F1 rats were orally treated for 6 weeks with vehicle or the vitamin D analogue alfacalcidol. Alfacalcidol treatment induced a 22% decrease in body mass and 17% muscle atrophy. Fibre atrophy was restricted to type IIb fibres in the low-oxidative part of the gastrocnemius medialis only (-22%; P < 0.05). There was a concomitant 1.6-fold increase in mRNA expression of the ubiquitin ligase MuRF-1 (P < 0.001), whereas those of insulin-like growth factor 1 and myostatin were not affected. Circulating IL-6 was unaltered, but leptin and adiponectin were decreased (-39%) and increased (64%), respectively. The treated rats also exhibited a reduced food intake. In conclusion, supraphysiological levels of circulating 1,25(OH)(2)D(3) cause preferential atrophy of type IIb fibres, which is associated with an increased expression of MuRF-1 without evidence of systemic inflammation. The atrophy and loss of body mass in the presence of supra-physiological levels of vitamin D are primarily due to a reduced food intake.

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.

Effects of alfacalcidol on the contractile properties of the gastrocnemius medialis muscle in adult and old rats

Vitamin D deficiency is associated with muscle weakness. It is unknown, however, how supra-physiological levels of vitamin D affect skeletal muscle. To investigate the effects of increased serum vitamin D (1,25 (OH)₂D₃ or 1,25D) levels on the contractile properties of the medial gastrocnemius muscle, adult and old female Fischer₃₄₄ x Brown Norway F1 rats were orally treated with vehicle or the vitamin D analogue alfacalcidol for 1 or 6 weeks. Alfacalcidol treatment resulted in elevated 1,25D serum levels. This was accompanied by hypercalcaemia and a reduction in body mass, the latter largely attributable to a reduced food intake. However, kidney function, as reflected by normal creatinine serum levels, as well as heart mass were unaffected. The 17% reduction in maximal isometric force and power was explicable by a similar loss of muscle mass. The force-frequency relationship of the 6-week-treated old rats was shifted to the left, but neither the shape of the force-velocity relationship nor the fatigability of the muscle were altered. Supra-physiological doses of vitamin D were accompanied by significant reductions in body and muscle mass, but not by an improvement in muscle functioning. Weight loss was largely due to a reduced food intake, while the left shift in the force-frequency relation may be due to increased 1,25D levels.

[Examination of effects of alfacalcidol vitamin D supplement and renal function on improvement in the physical fitness of pre-frail elderly persons attending a nursing care prevention class]

AIM

A characteristic condition of pre-frail elderly people is decreased mobility, which is associated with vitamin D levels and renal function. The aim of this study was to examine the association between physical fitness improvement and vitamin D levels, vitamin D supplements, and renal function in pre-frail elderly people.

METHODS

We conducted a longitudinal study in 2 towns from June 2006 to December 2009. Subjects consisted of 177 community-dwelling pre-frail elderly people aged 65 years and over (mean±standard deviation [SD]: 76.4±5.5 yrs) who attended a nursing care prevention program for 3 months. An interview was conducted based on a questionnaire. Serum levels of intact parathyroid hormone (iPTH), 25-hydroxyvitamin D(25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)(2)D), creatinine, and calcium were measured. eGFR (ml/min/1.73 m(2)) was calculated using a new formula. Alfacalcidol 1 µg/day was administered to subjects for 3 months, and we assumed that the elderly who took vitamin D (VD) of more than 80% of the recommended daily allowance to be the VD group. Walking ability, balance, and muscle strength physical fitness tests were performed.

RESULTS

The prevalence of eGFR <60.0 ml/min/1.73 m(2) was about 24.3%, and that of 25(OH)D <75 nmol/L was 86.4%. Pre-eGFR level and vitamin D supplementation with FR, pre-eGFR and pre 25(OH)D ≥45 nmol/L were associated with improvement in the timed up and go (TUG) test, pre-25(OH)D level (<50 nmol/L, ≥50 nmol/L) was associated with the tandem stance test, pre 25(OH)D level (<67.5 nmol/L, ≥67.5 nmol/L) was associated with the alternate step and 5 chair sit-to-stands tests, and post 1,25(OH)(2)D (<44 pg/ml, ≥44 pg/ml) was associated with the tandem walk tests.

CONCLUSIONS

These results suggest that the assessment of renal function and maintenance of appropriate vitamin D levels are important for the independent living of pre-frail elderly people. Ideally, a 25(OH)D level greater than 67.5 nmol/L is preferable.

Comparison of the effects of eldecalcitol and alfacalcidol on bone and calcium metabolism

Eldecalcitol [ED-71, 2beta-(3-hydroxypropyloxy)-1,25-dihydroxyvitamin D3] increases lumbar and hip bone mineral density (BMD) in a dose-dependent manner in osteoporotic patients with vitamin D supplementation. However, there has been no head-to-head comparison of the effects of eldecalcitol with alfacalcidol on bone and calcium metabolism in human subjects. Therefore, a randomized open-label clinical trial was conducted to compare the effect of eldecalcitol on bone turnover markers and calcium metabolism in 59 Japanese postmenopausal women. Subjects were randomly assigned to receive 1.0 microg alfacalcidol, 0.5 or 1.0 microg eldecalcitol once a day for 12 weeks. There was almost no increase in serum calcium (Ca) throughout the study period. Eldecalcitol from 0.5 to 1.0 microg increased daily urinary Ca excretion in a dose-dependent manner, and 1.0 microg eldecalcitol increased urinary Ca to a similar extent to 1.0 microg alfacalcidol. Both 0.5 and 1.0 microg eldecalcitol suppressed urinary NTX stronger than 1.0 microg alfacalcidol (-6, -30 and -35% in 1.0 microg alfacalcidol, 0.5 and 1.0 microg eldecalcitol-treated groups, respectively, at 12 weeks). In contrast, changes in serum BALP were similar among the three groups (-22, -22 and -29% in 1.0 microg alfacalcidol, 0.5 and 1.0 microg eldecalcitol-treated groups, respectively, at 12 weeks). These results demonstrate that 0.5-1.0 microg eldecalcitol can effectively inhibit bone resorption stronger than alfacalcidol with a similar effect on bone formation and a comparable effect on urinary Ca excretion, and suggest that eldecalcitol may have a better osteoprotective effect than alfacalcidol.

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 administration of an active vitamin D(3) analogue reduced the serum concentrations of 1-84 and truncated parathyroid hormone in pseudohypoparathyroidism type Ib patients

Serum calcium is one of major regulators of PTH amino-terminal (N-terminal) truncation and secretion of full-length (1-84)PTH from parathyroid glands. However, the effect of active vitamin D(3) on PTH truncations remains controversial. To determine whether active vitamin D(3) accelerates the truncation of PTH, the vitamin D(3) analogue alfacalcidol was administered to patients with pseudohypoparathyroidism type Ib (PHP Ib). Both the (1-84)PTH molecule and N-terminally truncated fragments such as (7-84)PTH can be measured by commercially available two-site total PTH (T-PTH) assays. The development of whole PTH (W-PTH) assays specific for full-length (1-84)PTH has enabled us to distinguish between N-terminally truncated PTH and full-length (1-84)PTH. W-PTH/T-PTH ratios were calculated and used as an index of PTH N-terminal truncations. Both serum W-PTH and T-PTH levels were elevated in untreated PHP Ib patients. The administration of alfacalcidol reduced both the W-PTH and T-PTH levels; however, the W-PTH/T-PTH ratios were stable. Serum calcium levels were significantly and negatively correlated with both the W-PTH and T-PTH levels, but not with the W-PTH/T-PTH ratios. Thus, the administration of an active vitamin D(3) analogue did not seem to have a major effect on the rate of PTH N-terminal truncation, even though it did reduce the secretion of both full-length and truncated PTH. Possibly, active vitamin D(3) attenuates the effect of elevated calcium on PTH N-terminal truncation in PHP Ib patients.

Regulation of steroid receptor expression by 1alpha-hydroxyvitamin D5 in hormone-responsive breast cancer cells

BACKGROUND

Vitamin D analog, 1alpha-hydroxy-24-ethyl-cholecalciferol (1alpha(OH)D5), is a less toxic VDR agonist that suppresses proliferation of breast cancer cells in vitro and in vivo. The present study assessed 1alpha(OH)D5-mediated regulation of VDR, and its potential anti-estrogenic activity in BT-474 cells.

MATERIALS AND METHODS

The mRNA and protein expression of steroid receptors were determined using RT-PCR and Western blot analyses, respectively.

RESULTS

VDR mRNA was up-regulated (180% of control) by 1alpha(OH)D5 within seven hours, whereas the expression of VDR protein increased by two-fold in 24 hours. This increase was abolished in presence of either actinomycin D or cyclohexamide. Additionally, there was a four-fold decrease in ERalpha mRNA and 40% decrease in ERalpha protein after 28 and 48 hours following 1alpha(OH)D5 treatment, respectively. Down-regulation of some of the estrogen-inducible genes was observed.

CONCLUSION

Although no VDR stabilization by 1alpha(OH)D5 was observed, there was an increased expression of the VDR followed by partial anti-estrogenic activity in hormone-responsive BT-474 cells.

Comparison of the effects of alendronate and alfacalcidol on hip bone mineral density and bone turnover in Japanese men having osteoporosis or osteopenia with clinical risk factors for fractures

PURPOSE

The comparative effects of alendronate and alfacalcidol on bone mineral density (BMD) and bone turnover have already been established in postmenopausal women with osteoporosis. An open-labeled prospective study was conducted to compare the treatment effects of alendronate and alfacalcidol on hip BMD and bone turnover in Japanese men with osteoporosis or osteopenia with clinical risk factors for fractures.

MATERIALS AND METHODS

One hundred twelve men with osteoporosis or osteopenia with clinical risk factors for fractures (mean age: 71.4 years) were randomly divided into two groups of 56 patients each: the alendronate (5 mg daily) and alfacalcidol (1 microg daily) groups. The BMD of the total hip, urinary level of cross-linked N-terminal telopeptides of type I collagen (NTX), and serum levels of bone-specific alkaline phosphatase (BSAP) were measured during the 12-month-treatment period.

RESULTS

Forty-five patients in the alendronate group and 42 patients in the alfacalcidol group completed the trial. Alendronate increased BMD (+2.3% at 12 months) following reductions in the urinary level of NTX (-46.4% at 3 months) and serum level of BSAP (-34.1% at 12 months), while alfacalcidol sustained BMD (-1.9% at 12 months) as well as the urinary level of NTX (+13.2% at 3 months) and serum level of BSAP (+1.8% at 12 months).

CONCLUSION

The present study confirmed that alendronate has better efficacy than alfacalcidol (active control) in increasing hip BMD and reducing bone turnover in Japanese men with osteoporosis or osteopenia with clinical risk factors for fractures.

Alfacalcidol prevents aromatase inhibitor (Letrozole)-induced bone mineral loss in young growing female rats

Long-term aromatase inhibitor use causes bone loss and increases fracture risk secondary to induced estrogen deficiency. We postulated that alfacalcidol (A; vitamin D(3) analog) could help prevent the Letrozole (L)-induced mineral bone loss. Fifty intact 1-month-old female rats were randomly divided into basal group; age-matched control group (AMC); L group: oral administration of 2 mg/kg per day; A group: oral administration of 0.1 microg/kg per day; and group L+A for a period of 8 weeks. Eight-week administration of L resulted in a significant increase in body weight, bone length, bone area, bone formation, and bone resorption activities when compared with the AMC group. However, the bone mass and bone mineral density (BMD) were significantly lower than the AMC group. Serum levels of testosterone, LH, FSH, and IGF-1 were significantly higher and serum estrone and estradiol were lower along with a decrease in ovary+uterus horn weight, when compared with the AMC groups. None of those parameters were affected by A treatment, except suppression of bone resorption activities and increased trabecular bone mass and femoral BMD, when compared with the AMC group. Results of L+A combined intervention showed that bone length, bone area, and bone formation activities were higher than the AMC group, and the bone resorption activities were lower and BMD was significantly higher than that of the L group. This study demonstrates that the combined intervention of L and A not only enhances bone growth, but also increases bone density, and the effects of L and A are independent and additive.

Protective effects of 1-alpha-hydroxyvitamin D3 on residual beta-cell function in patients with adult-onset latent autoimmune diabetes (LADA)

BACKGROUND

Previous in vitro and in vivo studies have demonstrated that vitamin D could prevent pancreatic beta-cell destruction and reduce the incidence of autoimmune diabetes. In children with type 1 diabetes, vitamin D treatment produces moderate protective effects on residual beta-cell function and has proven to be safe. Therefore, we hypothesized that vitamin D might have protective effects on beta-cell function in patients with latent autoimmune diabetes in adults (LADA), a form of slowly progressive autoimmune type 1 diabetes.

METHODS

Thirty-five patients with LADA were randomly assigned to receive subcutaneous insulin alone (n = 18) or insulin plus 1-alpha-hydroxyvitamin D3 (1-alpha(OH)D3; 0.5 microg per day) (n = 17) for 1 year. Plasma C-peptide levels in fasting state (FCP) and 2 h after 75-g glucose load (PCP) were measured every 6 months with radioimmunoassay.

RESULTS

Both FCP and PCP levels stayed steady in the insulin plus 1-alpha(OH)D3 group, while FCP decreased in insulin-alone group (P = 0.006) during the 12-month intervention. Seventy percent of patients treated with 1-alpha(OH)D3 maintained or increased their FCP concentrations after 1 year of treatment, while only 22% of patients treated with insulin alone maintained stable FCP levels (P < 0.01). Further analysis on LADA subgroups with different durations of diabetes demonstrated that islet beta-cell function was better preserved (as reflected by significantly higher FCP and PCP levels) in the 1-alpha(OH)D3 plus insulin group only in patients with diabetes duration no longer than 1 year. No severe side effects were observed in any group.

CONCLUSION

Our data suggest that 1-alpha(OH)D3 plus insulin therapy can preserve pancreatic beta-cell function in patients with LADA.

Alfacalcidol increases cancellous bone in low turnover, fatty marrow sites in aged, orchidectomized rats

The objectives of this study were to determine the responses of cancellous bone in the distal tibial metaphysis (DTM), a low turnover, fatty (yellow) marrow site, to sham-aged, orchidectomy (ORX) and alfacalcidol treatment in sham-aged and ORX rats. Eighteen-month-old male sham and ORX rats were treated with 0.1 and 0.2 microg/kg alfacalcidol 5 days/wk p.o. for 12 weeks, double fluorescent labeled, and the DTM were processed for bone histomorphometry analyses. The current study found the DTM in sham-aged male rats were resistant to age-related and ORX-induced cancellous bone loss and alfacalcidol-induced bone gain, findings that differ from that in the proximal tibial metaphysis (PTM) and lumbar vertebral body (LVB), two high turnover, red marrow bone sites. However, alfacalcidol treatment increased DTM bone mass in ORX rats where bone turnover was elevated by androgen deficiency. These results in concert with the previously positive findings in red marrow bone sites following alfacalcidol treatment suggest that alfacalcidol is more effective in increasing cancellous bone mass in the skeletal sites with higher bone turnover.

The effect of 1-alpha-hydroxycholecalciferol on the renal handling of phosphate in parathyroidectomized man

In a previous investigation by our group it was suggested that the stimulating effect of 1-alpha-hydroxycholecalciferol (1-alpha-OH-D3) on the tubular reabsorption of phosphate is mediated via the parallel suppression of the parathyroid hormone (PTH). A direct effect of 1-alpha-OH-D3 on the renal tubule could however not be completely excluded. Therefore, the effect of 1-alpha-OH-D3 was studied in 5 totally parathyroidectomized patients, in whom concomitant suppression of PTH would not occur. TmP/GFR, i.e. the ratio between the maximal tubular reabsorption of phosphate (TmP) and the glomerular filtration rate (GFR), was used as an indicator of the renal handling of phosphate. Estimation of TmP/GFR was performed 1) when the patients were vitamin D depleted and hypocalcemic, and 2) after 14-27 days of treatment with 1-alpha-OH-D3 to obtain stable normocalcemia. In patients with absent parathyroid function, no effect of 1-alpha-OH-D3 on TmP/GFR could be demonstrated. It is therefore concluded that 1-alpha-OH-D3 exhbits no antiphosphaturic effect in the absence of PTH and that the previously demonstrated antiphosphaturic effect of 1-alpha-OH-D3 in man is mediated via a concomitant suppression of PTH.

1-Alpha-hydroxycholecalciferol-induced changes in the renal heandling of phosphate and the serum parathyroid hormone level

The effect of 1-alpha-hydroxycholecalciferol (1alpha-OH-D3) on the renal handling of phosphate and the immunoreactive parathyroid hormone in serum (i-PTH) has been studied in 10 patients with a wide range of glomerular filtration rate (GFR), maximal tubular reabsorption of phosphate (TmP) and i-PTH. The patients were treated with 2 mug 1alpha-OH-D3 per day for approximately 80 days. Before and after this period of treatment, the TmP, i-PTH, 51Cr EDTA clearance, extracellular volume, standard bicarbonate, and serum calcium were measured in each patient. The TmP/GFR ratio was used as an index of the renal handling of phosphate. The index increased significantly (mean 26.5%, p less than 0.01) during the treatment, while i-PTH decreased significantly (mean 37.0%. p less than 0.01). An inverse significant correlation was demonstrated between TmP/GFR index and i-PTH both before (r = -0.87, p less than 0.001) and after (r = -0.79, p less than 0.01) the administration o alpha-OH-D3, while none of the other factors investigated were correlated to the index. It is concluded that 1alpha-OH-D3 increases the TmP/GFR index and reduces i-PTH in a parallel manner and it is therefore suggested that the 1alpha-OH-D3-induced changes in the renal handling of phosphate may be explained as being mediated solely via the suppression of i-PTH.

Effects of risedronate or alfacalcidol on bone mineral density, bone turnover, back pain, and fractures in Japanese men with primary osteoporosis: results of a two-year strict observational study

Although osteoporosis in men is already a major public health problem, there is still a dearth of data about the effects of risedronate in male osteoporosis, especially in Japanese with primary osteoporosis. Therefore, the objective of our study was to investigate the effects of risedronate on bone mineral density (BMD), bone turnover, back pain, and fractures in these patients prospectively for two years (at baseline, three months, six months, twelve months, and twenty-four months) both longitudinally and compared with those of alfacalcidol. The subjects enrolled for this study were 66 Japanese male patients with untreated primary osteoporosis (mean age 63.52 +/- 8.7 years), who were divided into two groups (44 with risedronate and 22 with alfacalcidol). We measured BMD by dual energy X-ray absorptiometry at three sites-the lumbar spine, femoral neck, and distal radius. Risedronate treatment significantly increased BMD at the lumbar spine and at the femoral neck, reduced bone-specific alkaline phosphatase (BAP) and serum N-terminal telopeptide of type I collagen (NTx), and reduced back pain, both longitudinally and compared with alfacalcidol treatment. We observed a lower rate of incident fracture in risedronate users. However, multiple logistic regression analysis revealed that this trend was not statistically significant, possibly because of the small number of patients enrolled. These potentially beneficial effects of risedronate on bone in male patients with primary osteoporosis suggest the possibility that osteoporosis should be treated with risedronate regardless of gender in order to effectively prevent subsequent osteoporotic fractures.

Effects of alendronate and alfacalcidol on the femoral bone mass and bone strength in orchidectomized rats

The purpose of the present study was to compare the effects of alendronate (ALN) and alfacalcidol (ALF) on the femoral bone mass and bone strength in orchidectomized rats and to clarify the skeletal benefits of combined administration of ALN and ALF. Fifty male Sprague-Dawley rats, 3 months of age, were randomized by the stratified weight method into five groups: the age-matched control (CON), orchidectomy (ORX), ORX + ALN (2.5 microg/kg, s.c., 5 times a week), ORX + ALF (0.1 microg/kg, p.o., 5 times a week), and ORX + ALN + ALF groups. After 12 weeks of feeding, the femoral distal metaphysis and mid-diaphysis were processed for peripheral quantitative tomographic analysis and biomechanical testing. In the femoral distal metaphysis, ALN prevented the ORX-induced reduction in the trabecular volumetric bone mineral density (vBMD) and breaking energy, and ALF prevented the ORX-induced reduction in the trabecular vBMD and increased the breaking energy to values above those observed in the CON group. Both ALN and ALF increased the maximum load to values above those observed in the ORX group. The improvements in parameters described above were more pronounced when ALN and ALF were administered in combination. In the femoral mid-diaphysis, on the other hand, ALN did not significantly affect the cortical bone parameters, whereas ALF increased the cortical area and maximum load to values above those observed in the ORX group. Furthermore, no apparent benefit of combined administration of ALN and ALF was observed. These findings suggest differential effects of ALN and ALF on femoral bone mass and the beneficial effects of combined administration of ALN and ALF on the trabecular bone of the femur in ORX rats.

Metabolism of 1alpha-hydroxyvitamin D3 by cytochrome P450scc to biologically active 1alpha,20-dihydroxyvitamin D3

Cytochrome P450scc (CYP11A1) metabolizes vitamin D3 to 20-hydroxyvitamin D3 as the major product, with subsequent production of dihydroxy and trihydroxy derivatives. The aim of this study was to determine whether cytochrome P450scc could metabolize 1alpha-hydroxyvitamin D3 and whether products were biologically active. The major product of 1alpha-hydroxyvitamin D3 metabolism by P450scc was identified by mass spectrometry and NMR as 1alpha,20-dihydroxyvitamin D3. Mass spectrometry of minor metabolites revealed the production of another dihydroxyvitamin D3 derivative, two trihydroxy-metabolites made via 1alpha,20-dihydroxyvitamin D3 and a tetrahydroxyvitamin D3 derivative. The Km for 1alpha-hydroxyvitamin D3 determined for P450scc incorporated into phospholipid vesicles was 1.4 mol substrate/mol phospholipid, half that observed for vitamin D3. The kcat was 3.0 mol/min/mol P450scc, 6-fold lower than that for vitamin D3. 1alpha,20-Dihydroxyvitamin D3 inhibited DNA synthesis by human epidermal HaCaT keratinocytes propagated in culture, in a time- and dose-dependent fashion, with a potency similar to that of 1alpha,25-dihydroxyvitamin D3. 1alpha,20-Dihydroxyvitamin D3 (10 microM) enhanced CYP24 mRNA levels in HaCaT keratinocytes but the potency was much lower than that reported for 1alpha,25-dihydroxyvitamin D3. We conclude that the presence of the 1-hydroxyl group in vitamin D3 does not alter the major site of hydroxylation by P450scc which, as for vitamin D3, is at C20. The major product, 1alpha,20-dihydroxyvitamin D3, displays biological activity on keratinocytes and therefore might be useful pharmacologically.

Vitamin D receptor ligand therapy in chronic kidney disease

Chronic kidney disease is a growing public health concern, and secondary hyperparathyroidism is one of the most serious associated comorbidities. In healthy individuals, precisely controlled feedback loops dynamically modulate parathyroid hormone (PTH) levels. As kidney function declines, phosphate retention, decreased 1a,25-dihydroxyvitamin D3, and a tendency to hypocalcemia leads to overstimulation of PTH production and parathyroid hyperplasia. Vitamin D receptor (VDR) ligands are essential tools for controlling parathyroid activity. This review highlights the current clinical and biochemical VDR ligand studies, focusing on the differences between selective and nonselective VDR ligands. It is apparent that VDR ligands have important roles in the management of secondary hyperparathyroidism. Selective VDR ligands, in particular, may offer additional benefits in the treatment of bone disease, and may potentially reduce adverse effects related to cardiovascular disease.

Greater efficacy of alfacalcidol in the red than in the yellow marrow skeletal sites in adult female rats

The present study compared the bone anabolic effects of graded doses of alfacalcidol in proximal femurs (hematopoietic, red marrow skeletal site) and distal tibiae (fatty, yellow marrow skeletal site). One group of 8.5-month-old female Sprague-Dawley rats were killed at baseline and 4 groups were treated 5 days on/2 days off/week for 12 weeks with 0, 0.025, 0.05 and 0.1 microg alfacalcidol/kg by oral gavage. The proximal femur, bone site with hematopoietic marrow, as well as the distal tibia bone site with fatty marrow, were processed undecalcified for quantitative bone histomorphometry. In the red marrow site of the proximal femoral metaphysis (PFM), 0.1 microg alfacalcidol/kg induced increased cancellous bone mass, improved architecture (decreased trabecular separation, increased connectivity), and stimulated local bone formation of bone 'boutons' (localized bone formation) on trabecular surfaces. There was an imbalance in bone resorption and formation, in which the magnitude of depressed bone resorption greater than depressed bone formation resulted in a positive bone balance. In addition, bone 'bouton' formation contributed to an increase in bone mass. In contrast, the yellow marrow site of the distal tibial metaphysis (DTM), the 0.1 microg alfacalcidol/kg dose induced a non-significant increased cancellous bone mass. The treatment decreased bone resorption equal to the magnitude of decreased bone formation. No bone 'bouton' formation was observed. These findings indicate that the highest dose of 0.1 microg alfacalcidol/kg for 12 weeks increased bone mass (anabolic effect) at the skeletal site with hematopoietic marrow of the proximal femoral metaphysis, but the increased bone mass was greatly attenuated at the fatty marrow site of the distal tibial metaphysis. In addition, the magnitude of the bone gain induced by alfacalcidol treatment in red marrow cancellous bone sites of the proximal femoral metaphysis was half that of the lumbar vertebral body. The latter data were from a previous report from the same animal and protocol. These findings indicated that alfacalcidol as an osteoporosis therapy is less efficacious as a positive bone balance agent that increased trabecular bone mass in a non-vertebral skeletal site where bone marrow is less hematopoietic.

Effects of combined administration of alfacalcidol and risedronate on cancellous and cortical bone mass of the tibia in glucocorticoid-treated young rats

The purpose of the present study was to examine the effects of combined administration of alfacalcidol (ALF) and risedronate (RIS) on cancellous and cortical bone mass of the tibia in glucocorticoid (GC)-treated young rats. One hundred and nine female Sprague-Dawley rats, 3 months of age, were randomly divided by the stratified weight method into eleven groups according to the following treatment schedule: baseline control, a 4-week age-matched control, and a 4-week GC administration with a 4-week concomitant administration of vehicle, ALF, RIS, or ALF+RIS, and an 8-week age-matched control and 8-week GC administration with a 4-week administration of vehicle, ALF, RIS, or ALF+RIS that was initiated after a 4-week administration of GC. The GC (methylprednisolone sodium succinate, 5.0 mg/kg) and RIS (10 microg/kg) were administered subcutaneously 3 times a week. ALF (0.08 microg/kg) was administered orally 5 times a week. At the end of the experiment, static and dynamic bone histomorphometric analyses were performed on cancellous bone of the proximal tibial metaphysis and cortical bone of the tibial diaphysis. A 4-week GC administration induced a loss of cancellous bone volume/total tissue volume (BV/TV) compared with the age-matched control as a result of decreased bone formation and increased bone erosion, while an 8-week GC administration induced both losses of cancellous BV/TV and of percent cortical area (Ct Ar) compared with the age-matched control as a result of decreased trabecular bone formation and increased trabecular and endocortical bone erosion. ALF prevented the loss of cancellous BV/TV at the 4th week by mildly suppressing bone erosion without reducing bone formation, and it restored cancellous BV/TV and increased percentage of Ct Ar at the 8th week by preventing a reduction in trabecular bone formation and mildly suppressing trabecular bone erosion and by strongly suppressing endocortical bone erosion, respectively. RIS restored only cancellous BV/TV at 8 weeks by strongly suppressing bone formation and bone erosion. Combined administration of ALF and RIS increased total tissue area of cortical bone at the 4th and 8th weeks by markedly increasing periosteal bone formation. The present study showed the efficacy of combined administration of ALF and RIS for the geometry of cortical bone in GC-treated rats.

Alfacalcidol-stimulated focal bone formation on the cancellous surface and increased bone formation on the periosteal surface of the lumbar vertebrae of adult female rats

PURPOSE

To investigate the skeletal effects of alfacalcidol alone or in combination with exercise in intact adult female rats.

METHODS

Seventy-four 8.5-month-old rats were orally administered 0, 0.005, 0.025, 0.05 or 0.1 microg/kg of alfacalcidol for 12 weeks, alone or in combination with exercise. Cancellous bone histomorphometric measurements were performed on the second lumbar vertebra.

RESULTS

At 0.05 and 0.1 microg/kg, alfacalcidol caused a significant increase in cancellous bone volume, accompanied by an increase in trabecular architecture. Percent eroded surface, bone resorption and formation were suppressed by alfacalcidol treatment. However, mineral apposition rate was significantly increased, indicating osteoblast activity was increased. A positive balance between bone formation and resorption was observed in the rats treated with the highest dose of alfacalcidol. Alfacalcidol induced a unique bone formation site ("bouton") on the cancellous surface. These boutons connected adjacent trabeculae and increased trabecular thickness. They exhibited both smooth and scalloped cement lines, suggesting that they were formed by minimodeling- and remodeling-based bone formation. Furthermore, alfacalcidol at 0.1 microg/kg increased periosteal bone formation of the lumbar transverse processes. Bipedal stance exercise alone did not have an effect on bone balance and bone turnover. There were no interactions between alfacalcidol and bipedal stance exercise except for a decrease in bone resorption.

CONCLUSION

Alfacalcidol exhibited both anti-catabolic and anabolic effects on bone in intact female rats. The effect of combined treatment with alfacalcidol and bipedal stance exercise was no better than that of alfacalcidol alone.

Alfacalcidol treatment increases bone mass from anticatabolic and anabolic effects on cancellous and cortical bone in intact female rats

It has been reported that alfacalcidol had an anticatabolic and anabolic effect on bone in ovariectomized and aged male rat models, but this has not been tested on intact female rats. The current study was to determine the effects of alfacalcidol on cancellous and cortical bone in intact female rats with or without exercise. Seventy-four, 8.5-month-old, intact female rats were orally treated with 0, 0.005, 0.025, 0.05, or 0.1 microg/kg alfacalcidol alone or in combination with raised cage (RC) exercise for 3 months. In vivo peripheral quantitative computerized tomography (pQCT) of the proximal tibial metaphyses (PTM) and ex vivo histomorphometric analyses of the PTM and tibial shaft (TX) were performed. Only the 0.1 microg alfacalcidol/kg dose proved to be anabolic. pQCT analysis showed that this dose increased total and cortical bone mineral content and density and trabecular bone mineral density. Histomorphometrically, it induced an anabolic response by increased trabecular mass and microarchitecture from stimulated cancellous bone and bone bouton formations, and suppressed bone resorption more than bone formation on the trabecular and endocortical surfaces, to produce a positive bone balance. A positive correlation between trabecular connectivity and bone bouton numbers occurred. These findings suggest alfacalcidol treatment augments bone mass by increased cancellous bone mass and improved trabecular architecture through its anticatabolic and anabolic properties in the intact adult female rat. Last, raised cage exercise alone or the combination of raised cage and alfacalcidol was no more effective than alfacalcidol alone.