Multifunctional and potent roles of the 3-hydroxypropoxy group provide eldecalcitol's benefit in osteoporosis treatment

Identification of trans-genus biomarkers for early diagnosis of intestinal schistosomiasis and progression of gut pathology in a mouse model using metabolomics

Schistosomiasis is one of the most devastating human diseases worldwide. The disease is caused by six species of Schistosoma blood fluke; five of which cause intestinal granulomatous inflammation and bleeding. The current diagnostic method is inaccurate and delayed, hence, biomarker identification using metabolomics has been applied. However, previous studies only investigated infection caused by one Schistosoma spp., leaving a gap in the use of biomarkers for other species. No study focused on understanding the progression of intestinal disease. Therefore, we aimed to identify early gut biomarkers of infection with three Schistosoma spp. and progression of intestinal pathology. We infected 3 groups of mice, 3 mice each, with Schistosoma mansoni, Schistosoma japonicum or Schistosoma mekongi and collected their feces before and 1, 2, 4 and 8 weeks after infection. Metabolites in feces were extracted and identified using mass spectrometer-based metabolomics. Metabolites were annotated and analyzed with XCMS bioinformatics tool and Metaboanalyst platform. From >36,000 features in all conditions, multivariate analysis found a distinct pattern at each time point for all species. Pathway analysis reported alteration of several lipid metabolism pathways as infection progressed. Disturbance of the glycosaminoglycan degradation pathway was found with the presence of parasite eggs, indicating involvement of this pathway in disease progression. Biomarkers were discovered using a combination of variable importance for projection score cut-off and receiver operating characteristic curve analysis. Five molecules met our criteria and were present in all three species: 25-hydroxyvitamin D2, 1α-hydroxy-2β-(3-hydroxypropoxy) vitamin D3, Ganoderic acid Md, unidentified feature with m/z 455.3483, and unidentified feature with m/z 456.3516. These molecules were proposed as trans-genus biomarkers of early schistosomiasis. Our findings provide evidence for disease progression in intestinal schistosomiasis and potential biomarkers, which could be beneficial for early detection of this disease.

Effect of active vitamin D treatment on development of type 2 diabetes: DPVD randomised controlled trial in Japanese population

OBJECTIVE

To assess whether eldecalcitol, an active vitamin D analogue², can reduce the development of type 2 diabetes among adults with impaired glucose tolerance.

DESIGN

Double blinded, multicentre, randomised, placebo controlled trial.

SETTING

Three hospitals in Japan, between June 2013 and August 2019.

PARTICIPANTS

People aged 30 years and older who had impaired glucose tolerance defined by using a 75 g oral glucose tolerance test and glycated haemoglobin level.

INTERVENTIONS

Participants were randomised to receive active vitamin D (eldecalcitol 0.75 μg per day; n=630) or matching placebo (n=626) for three years.

MAIN OUTCOMES

The primary endpoint was incidence of diabetes. Prespecified secondary endpoints were regression to normoglycaemia and incidence of type 2 diabetes after adjustment for confounding factors at baseline. In addition, bone densities and bone and glucose metabolism markers were assessed.

RESULTS

Of the 1256 participants, 571 (45.5%) were women and 742 (59.1%) had a family history of type 2 diabetes. The mean age of participants was 61.3 years. The mean serum 25-hydroxyvitamin D concentration at baseline was 20.9 ng/mL (52.2 nmol/L); 548 (43.6%) participants had concentrations below 20 ng/mL (50 nmol/L). During a median follow-up of 2.9 years, 79 (12.5%) of 630 participants in the eldecalcitol group and 89 (14.2%) of 626 in the placebo group developed type 2 diabetes (hazard ratio 0.87, 95% confidence interval 0.67 to 1.17; P=0.39). Regression to normoglycaemia was achieved in 145 (23.0%) of 630 participants in the eldecalcitol group and 126 (20.1%) of 626 in the placebo group (hazard ratio 1.15, 0.93 to 1.41; P=0.21). After adjustment for confounding factors by multivariable fractional polynomial Cox regression analysis, eldecalcitol significantly lowered the development of diabetes (hazard ratio 0.69, 0.51 to 0.95; P=0.020). In addition, eldecalcitol showed its beneficial effect among the participants with the lower level of basal insulin secretion (hazard ratio 0.41, 0.23 to 0.71; P=0.001). During follow-up, bone mineral densities of the lumbar spine and femoral neck and serum osteocalcin concentrations significantly increased with eldecalcitol compared with placebo (all P<0.001). No significant difference in serious adverse events was observed.

CONCLUSIONS

Although treatment with eldecalcitol did not significantly reduce the incidence of diabetes among people with pre-diabetes, the results suggested the potential for a beneficial effect of eldecalcitol on people with insufficient insulin secretion.

TRIAL REGISTRATION

UMIN Clinical Trials Registry UMIN000010758.

The Vitamin D Receptor in Osteoblast-Lineage Cells Is Essential for the Proresorptive Activity of 1α,25(OH)2D3 In Vivo

We previously reported that daily administration of a pharmacological dose of eldecalcitol, an analog of 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], increased bone mass by suppressing bone resorption. These antiresorptive effects were found to be mediated by the vitamin D receptor (VDR) in osteoblast-lineage cells. Using osteoblast-lineage-specific VDR conditional knockout (Ob-VDR-cKO) mice, we examined whether proresorptive activity induced by the high-dose 1α,25(OH)2D3 was also mediated by VDR in osteoblast-lineage cells. Administration of 1α,25(OH)2D3 (5 μg/kg body weight/day) to wild-type mice for 4 days increased the number of osteoclasts in bone and serum concentrations of C-terminal crosslinked telopeptide of type I collagen (CTX-I, a bone resorption marker). The stimulation of bone resorption was concomitant with the increase in serum calcium (Ca) and fibroblast growth factor 23 (FGF23) levels, and decrease in body weight. This suggests that a toxic dose of 1α,25(OH)2D3 can induce bone resorption and hypercalcemia. In contrast, pretreatment of wild-type mice with neutralizing anti-receptor activator of NF-κB ligand (RANKL) antibody inhibited the 1α,25(OH)2D3-induced increase of osteoclast numbers in bone, and increase of CTX-I, Ca, and FGF23 levels in serum. The pretreatment with anti-RANKL antibody also inhibited the 1α,25(OH)2D3-induced decrease in body weight. Consistent with observations in mice conditioned with anti-RANKL antibody, the high-dose administration of 1α,25(OH)2D3 to Ob-VDR-cKO mice failed to significantly increase bone osteoclast numbers, serum CTX-I, Ca, or FGF23 levels, and failed to reduce the body weight. Taken together, this study demonstrated that the proresorptive, hypercalcemic, and toxic actions of high-dose 1α,25(OH)2D3 are mediated by VDR in osteoblast-lineage cells.

Hypercalcemia and acute kidney injury induced by eldecalcitol in patients with osteoporosis: a case series of 32 patients at a single facility

BACKGROUND

Eldecalcitol (ELD) is an active vitamin D3 analog that is widely used in Japan for the treatment of osteoporosis. The most common adverse drug reaction of ELD is hypercalcemia. However, few reports have focused on acute kidney injury (AKI) associated with ELD-induced hypercalcemia.

MATERIALS AND METHODS

We retrospectively reviewed the medical records at our hospital for cases of hypercalcemia-induced AKI between April 2013 and February 2018. Among them, we focused on patients who developed AKI secondary to ELD-induced hypercalcemia.

RESULTS

Among 69 patients who developed hypercalcemia-induced AKI, 32 patients (46.4%) developed AKI associated with ELD-induced hypercalcemia. Their mean age was 82 ± 5 years, 97% of them were female, mean corrected serum calcium level was 12.2 ± 1.5 mg/dL, serum creatinine level was 2.5 ± 2.2 mg/dL, and estimated glomerular filtration rate was 23.9 ± 14.4 ml/min/1.73 m2 on admission. ELD administration was discontinued in all patients and some of them were treated with hydration with or without calcitonin, which was followed by a normalization of serum calcium level. Corrected serum calcium level on admission was significantly higher (p < .05) in patients treated with magnesium oxide. Although there were no significant differences, serum calcium and creatine levels on admission tended to be higher in patients who were treated with other drugs that affect renal hemodynamics and renal calcium metabolism than those not taking these drugs.

CONCLUSIONS

Prescribers of ELD should regularly monitor serum calcium levels and kidney function to prevent hypercalcemia and AKI associated with ELD and pay more attention to concomitant drugs especially magnesium oxide.

Sequential Treatment with Eldecalcitol After PTH Improves Bone Mechanical Properties of Lumbar Spine and Femur in Aged Ovariectomized Rats

Parathyroid hormone (PTH) analogs have a powerful anabolic effect on bone and are used in the treatment of patients with severe osteoporosis. However, there are limitations to how long they can be safely administered. Withdrawal of PTH results in the cancelation of its effects, necessitating subsequent treatment to maintain the bone quantity and quality. This study assessed the effects of Eldecalcitol (ELD), an active vitamin D3 derivative, after PTH in estrogen-deficient osteoporotic rats. Six-month-old female rats were ovariectomized, and PTH administration was started 7 weeks later. After 4 weeks of PTH treatment, the animals were divided into three groups and either continued to receive PTH (PTH-PTH), or were switched to ELD (PTH-ELD) or vehicle (PTH-Veh) for an additional 4 weeks. In the femur, increased BMD by 4 weeks treatment of PTH was significantly reduced in PTH-Veh but not in PTH-PTH and PTH-ELD. The same tendency was observed in the lumbar vertebrae. MicroCT imaging and histomorphometry analysis revealed that the favorable bone structure changes by PTH administration were also maintained in the femurs and tibias of the PTH-PTH and PTH-ELD groups. Increased bone strength by 4-week treatment of PTH in lumber also maintained in PTH-ELD. Furthermore, minimodeling was observed in the PTH-ELD group. These results demonstrate that treatment with ELD sequentially following PTH prevented the bone quantity and strength reduction that accompanies PTH withdrawal in estrogen-deficient rats.

Eldecalcitol (ED-71), an analog of 1α,25-dihydroxyvitamin D3 as a potential anti-cancer agent for oral squamous cell carcinomas

We have previously reported that 1,25(OH)₂D₃ inhibits NF-κB activity and thus inhibits growth of OSCC cells in serum-free culture and down-regulates HBp17/FGFBP-1 expression, which is important for cancer cell growth and angiogenesis. Here, we have investigated the effects of ED-71, an analog of vitamin D3 (VD) on OSCC cell lines in serum-free culture. It is known that ED-71 has a stronger inhibitory effect on bone resorption compared to VD and other VD analogs. To the best of our knowledge, there was no report examining the potential of ED-71 as an anti-cancer agent for OSCC. We found that ED-71 is able to inhibit the growth of cancer cell lines at a concentration of hundred times lower than calcitriol. As Cyp24A1 was reportedly induced in cancer cells, we measured the expression of CYP24A1 in OSCC cell lines (NA and UE), A431 epidermoid carcinoma and normal fibroblast cell (gfi) in serum-free culture. As a result, CYP24A1 mRNA and the protein expression in the OSCC cells treated with ED-71 increased in a dose-dependent manner. However, in vivo experiment, in which the A431 cells were implanted in mice, tumor formation was reduced by the ED-71 treatment with no significant difference between Cyp24A1 expression in the tumors of ED-71-treated and control group, as analyzed by western blotting and immunohistochemistry. These results suggest that ED-71 is a potential anti-cancer agent for OSCC.

Effects of eldecalcitol on cortical bone response to mechanical loading in rats

Background

Mechanical loading of bones activates modeling and suppresses remodeling by promoting bone formation. Eldecalcitol is approved for the treatment of osteoporosis in Japan and is often used in patients undergoing exercise therapy. However, the effects of eldecalcitol on bone formation during mechanical loading are unknown. The aim of this study was to clarify the influence of eldecalcitol administration on bone response to mechanical loading using a four-point bending device.

Methods

Forty six-month-old female Wistar rats were randomized into four groups based on eldecalcitol dose (vehicle administration (VEH), low dose (ED-L), medium dose (ED-M), and high dose (ED-H)). Loads of 38 N were applied in vivo to the right tibia for 36 cycles at 2 Hz, by four-point bending, 3 days per week for 3 weeks. After calcein double-labeling, rats were sacrificed and tibial cross sections were prepared from the region with maximal bending at the central diaphysis. Histomorphometry was performed on the entire periosteal and endocortical surface of the tibiae, dividing the periosteum into lateral and medial surfaces.

Results

The effects of external loading on bone formation parameters were significant at all three surfaces. Bone formation parameters were highest in the ED-H group, and the effects of eldecalcitol on bone formation rate were significant at the endocortical surface. In addition, the interaction between loading and eldecalcitol dose significantly affected bone formation rate at the endocortical surface.

Conclusions

Eldecalcitol enhanced the cortical bone response to mechanical loading and a synergistic effect was observed in a rat model.

Human hepatic metabolism of the anti-osteoporosis drug eldecalcitol involves sterol C4-methyl oxidase

The metabolism of eldecalcitol (ED-71), a 2β-hydroxypropoxylated analog of the active form of vitamin D₃ was investigated by using in vitro systems. ED-71 was metabolized to 1α,2β,25-trihydroxyvitamin D₃ (1α,2β,25(OH)₃D₃) in human small intestine and liver microsomes. To identify the enzymes involved in this metabolism, we examined NADPH-dependent metabolism by recombinant P450 isoforms belonging to the CYP1, 2, and 3 families, and revealed that CYP3A4 had the activity. However, the CYP3A4 -specific inhibitor, ketoconazole, decreased the activity in human liver microsomes by only 36%, suggesting that other enzymes could be involved in ED-71 metabolism. Because metabolism was dramatically inhibited by cyanide, we assumed that sterol C4-methyl oxidase like gene product (SC4MOL) might contribute to the metabolism of ED-71. It is noted that SC4MOL is physiologically essential for cholesterol synthesis. Recombinant human SC4MOL expressed in COS7, Saccharomyces cerevisiae, or Escherichia coli cells converted ED-71 to 1α,2β,25(OH)₃D₃. Furthermore, we evaluated the metabolism of ED-71 by recombinant CYP24A1, which plays an important role in the metabolism of the active form of vitamin D₃ (1α,25(OH)₂D₃) and its analogs. The k_cat/K_m value for 24- or 23-hydroxylation of ED-71 was only 3% of that for 1α,25(OH)₂D₃, indicating that ED-71 was resistant to CYP24A1-dependent catabolism. Among the three enzymes catalyzing ED-71, SC4MOL appears to be most important in the metabolism of ED-71. To the best of our knowledge, this is the first study showing that SC4MOL can function as a drug-metabolizing enzyme. The yeast and E. coli expression systems for SC4MOL could be useful for structure-function analyses of SC4MOL.

Synthesis and metabolic studies of 1α,2α,25-, 1α,4α,25- and 1α,4β,25-trihydroxyvitamin D3

Three different A-ring perhydroxylated trihydroxyvitamin D3 metabolites were synthesized from their appropriate A-ring precursors and CD-ring for their potential therapeutic applications. We first chemically synthesized 1α,2α,25-trihydroxyvitamin D3 [1α,2α,25(OH)3D3] to study its VDR binding affinity because this metabolite is a product of recombinant human CYP3A4 catalysis when 2α-(3-hydroxypropoxy)-1α,25-dihydroxyvitamin D3 (O2C3), a more potent vitamin D receptor (VDR) binder than 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], is used as the substrate. We found that this metabolite retained 27.3% of the VDR binding affinity compared to 1α,25(OH)2D3. The kcat/Km value of CYP24A1 for 1α,2α,25(OH)3D3 is 60% of that for 1α,25(OH)2D3. Since the biological activity and the metabolic fate of a naturally occurring C4-hydroxylated vitamin D2 metabolite found in the serum of rats treated with pharmacological doses of vitamin D2 have never been described, we next synthesized 1α,4α,25-trihydroxyvitamin D3 and its diastereoisomer, 1α,4β,25-trihydroxyvitamin D3, to study their metabolism and biological activities. Both 4-hydroxylated isomers showed weaker VDR binding affinity than 1α,25(OH)2D3. Although either 4-hydroxylated isomer can be metabolized by CYP24A1 almost at the same level as 1α,25(OH)2D3, their metabolic patterns catalyzed by uridine 5'-diphosphoglucuronosyltransferase (UGT) are different; only the 4α-hydroxylated analog can be metabolized by UGT to produce a glucuronate conjugate. The results provide important information for the synthesis of new novel chemotherapeutic vitamin D analogs which would be less subjective to degradation and therefore more bioavailable than 1α,25(OH)2D3. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.

Eldecalcitol reduces osteoporotic fractures by unique mechanisms

Eldecalcitol shows higher binding affinity for vitamin D-binding protein (DBP), tighter binding to vitamin D receptor (VDR), and resistance to metabolic degradation via 24-hydroxylation. In silico analysis of the mode of binding demonstrated that the 3-hydroxypropyloxy (3-HP) group of eldecalcitol offers additional hydrogen bond and CH-π interaction for the binding to DBP and VDR. However, the 3-HP group interferes with the binding of eldecalcitol to CYP24A1, causing poor metabolic clearance of eldecalcitol by this enzyme. These characteristics may contribute to the stronger effect of eldecalcitol than calcitriol. The present post-hoc analysis also demonstrate that the incidence of hypercalcemia and hypercalciuria is slightly higher in eldecalcitol than in alfacalcidol group especially in patients with CKD stage 3B, that both serum and urinary calcium return to the baseline levels shortly after cessation of the treatment in both treatment groups, that the incidence of urolithiasis is higher in patients with higher eGFR and is similar between alfacalcidol and eldecalcitol groups, and that eGFR is transiently reduced by both alfacalcidol and eldecalcitol treatment especially among patients with higher eGFR but recovers after the end of both treatment. Eldecalcitol can be used for the treatment of osteoporosis without Ca supplementation to reduce the incidence of hypercalcemia and hypercalciuria, and enough hydration is recommended in order to avoid hypercalcemia, urolithiasis and deterioration of renal function.