Alfacalcidol in men with osteoporosis: a prospective, observational, 2-year trial on 214 patients

Roles of active forms of vitamin D in supporting innate immune systems and in reducing excess inflammation in COVID-19

A reduced supply of micronutrient vitamin D leads to a more severe course of coronavirus infection (COVID-19). Vitamin D deficiency is combined with a decrease in innate antiviral immunity and excess of inflammation. Vitamin D supplementation stimulates the synthesis of antibacterial peptides and is important for weakening the cytokine storm, reducing excessive acute and chronic inflammation, and also for compensating for chronic comorbid pathologies. Active forms of vitamin D (alfacalcidol, etc.) are of particular importance for compensating for vitamin D deficiency in elderly patients, endocrine-immune dysfunction, sarcopenia, chronic renal failure (in which the metabolism of vitamin D in the kidneys is disturbed).

Nociception: the roles of vitamin D

Objective: to carry out a systematic computer-assisted analysis of scientific literature on on the relationships between the effects of vitamin and nociception (including the impact of vitamin D deficiency on the development of pain syndrome.

Material and methods. For the query “(pain OR nociception) AND (vitamin D OR cholecalciferol OR VITD OR CALCITRIOL OR HYDROXYVITAMIN OR DIHYDROXYVITAMIN OR ALPHACALCIDOL)", 2318 references, including 77 references on alpha-calcidol, were found in the biomedical publications database PubMed. The computer-assisted analysis of this array of publications was carried out using the current big data analysis methods developed within the topological and metric approaches to recognition/classification problems.

Result and discussion. A systematic computer-assisted text analysis of 2318 studies on the relationships between nociception and vitamin D showed that the analgesic effects of the vitamin are by anti-inflammatory action and the regulation of serotonergic, dopaminergic, and opioidergic neurotransmission. The lower blood levels of the major vitamin D metabolite 25 (OH)D is a risk factor for decreased pain threshold in myalgia, fibromyalgia, arthralgia, dorsalgia, and a number of neuralgias.

Conclusion. In patients with impaired renal conversion of active vitamin D metabolites (especially in the elderly), the efficacy of cholecalciferol-based drugs is reduced, which makes it necessary to use the active forms of vitamin D.

Plain vitamin D or active vitamin D in the treatment of osteoporosis: where do we stand today?

Osteoporosis is a major cause of morbidity and mortality worldwide and its prevention in order to avert fractures was considered of great importance in maintaining well-being and independence among the elderly. Strategies for osteoporosis prevention are well delineated, but research shows that the treatment options offered today could still be improved. The role of plain vitamin D (cholecalciferol) in bone health and the prevention of osteoporosis are well documented; however, as a treatment for osteoporosis, either with or without calcium, it has been shown to be ineffective. This is due in part to the strong negative feedback mechanisms in place in vitamin D-replete patients. However, other factors linked directly to ageing such as oestrogen depletion, reduced kidney or liver function may also be involved in reducing the body's capability to activate plain vitamin efficiently. This is why active vitamin D analogues such as alfacalcidol, 1-α-(OH)D3, are of clinical interest. Alfacalcidol requires only one hydroxylation reaction to become active 1,25-(OH)2-vitamin D3, and the 25-hydroxylase catalyzing this reaction is found in the liver and also interestingly in osteoblasts suggesting a local effect. Registered for use in postmenopausal osteoporosis, in most countries worldwide, alfacalcidol has also shown efficacy in glucocorticoid-induced and male osteoporosis. The present review provides compelling evidence for the efficacy of this compound in the treatment of osteoporosis and prevention of fractures both in monotherapy and when combined with other osteoporotic drugs where additive effects are clear. The safety profile of alfacalcidol is shown to be highly acceptable and it is considered less likely to induce hypercalcaemia than another more widely used analogue, calcitriol. Therefore, it remains unclear as to why alfacalcidol is not more widely used in clinical practice.

[Treatment of rheumatic disease with renal insufficiency]

BACKGROUND

Reduced renal function is not rare in patients with inflammatory rheumatic diseases and is associated with an increased risk of treatment-induced and perioperative adverse events.

METHOD

A literature search was carried out for the medical treatment and perioperative management of rheumatic disease in the presence of renal insufficiency.

RESULTS

Patients with rheumatic disease and renal insufficiency have a higher risk of cardiovascular disease, bone loss and immunodeficiency than those without kidney disease. The perioperative rate of cardiovascular and infectious complications and the risk of acute kidney failure are elevated in these patients. The pharmacokinetics of many drugs used in rheumatology is influenced by the kidney function. Especially methotrexate is contraindicated in patients with an estimated glomerular filtration rate (eGFR) <45 ml/min. Nonsteroidal anti-inflammatory drugs (NSAIDS) and cyclooxygenase (COX)-2 inhibitors should not be used with renal insufficiency or only for a short term with the lowest effective dose. The treatment of osteoporosis with antiresorptive drugs may lead to adynamic bone disease in advanced kidney disease, and, therefore, the use of these drugs is controversial.

CONCLUSION

Medication should be modified in patients with rheumatic disease and kidney involvement according the grade of renal insufficiency. There is also a need for special perioperative management in these patients, with interdisciplinary cooperation of rheumatologists, nephrologists and orthopedic doctors.

25 S-Adamantyl-23-yne-26,27-dinor-1α,25-dihydroxyvitamin D3: Synthesis, Tissue Selective Biological Activities, and X-ray Crystal Structural Analysis of Its Vitamin D Receptor Complex

Both 25 R- and 25 S-25-adamantyl-23-yne-26,27-dinor-1α,25-dihydroxyvitamin D₃ (4a and 4b) were stereoselectively synthesized by a Pd(0)-catalyzed ring closure and Suzuki-Miyaura coupling between enol-triflate 7 and alkenyl-boronic ester 8. The 25 S isomer (4b) showed high vitamin D receptor (VDR) affinity (50% of that of the natural hormone 1α,25-dihydroxyvitamin D₃, 1) and transactivation potency (kidney HEK293, 90%). In endogenous gene expression, it showed high cell-type selectivity for kidney cells (HEK293, CYP24A1 160% of 1), bone cells (MG63, osteocalcin 64%), and monocytes (U937, CAMP 96%) over intestine (SW480, CYP24A1 8%) and skin (HaCaT, CYP24A1 7%) cells. The X-ray crystal structural analysis of 4b in complex with rat VDR-ligand binding domain (LBD) showed the highest Cα positional shift from the 1/VDR-LBD complex at helix 11. Helix 11 of the 4b and 1 VDR-LBD complexes also showed significant differences in surface properties. These results suggest that 4b should be examined further as another candidate for a mild preventive osteoporosis agent.

Alfacalcidol Increases the Therapeutic Efficacy of Ibandronate on Bone Mineral Density in Japanese Women with Primary Osteoporosis

Bisphosphonates (BPs) increase bone mineral density (BMD) through the inhibition of osteoclast activity. Among BPs, ibandronate (IBN) is a strong inhibitor of bone resorption. However, the effects of a vitamin D analogue, alfacalcidol (ALF), on IBN treatment for osteoporosis is unknown. Fifty-three treatment-naïve post-menopausal women with primary osteoporosis were recruited and divided into IBN-treatment group (IBN group) and IBN with ALF group (IBN/ALF group). IBN (1.0 mg) was intravenously injected once a month, with or without oral ALF (1.0 μg/day). Ultimately, 19 subjects in IBN group and 26 in IBN/ALF group were analyzed. Bone turnover markers were examined at 4, 6, 12, and 18 months, and BMD was measured at 6, 12, and 18 months. Compared with pre-treatment, bone turnover markers significantly decreased in both groups after 4 months. The levels of serum N-terminal propeptide of type-1 procollagen and tartrate-resistant acid phosphatase-5b, and urinary N-terminal telopeptide of type-I collagen were significantly lower in IBN/ALF group than those in IBN group at 12 months. Lumbar 1-4 (L)-BMD significantly increased from 6 months in IBN/ALF group and at 18 months in IBN group. L-BMD was significantly higher in IBN/ALF group (6.6% increase) than in IBN group (3.4%) at 18 months. Total hip (H)-BMD significantly increased from 6 months in IBN/ALF group and tended to improve in IBN group. H-BMD was significantly higher in IBN/ALF group (4.8%) than in IBN group (3.2%) at 18 months. In conclusion, treatment with ALF in combination with IBN improves BMD in post-menopausal women with osteoporosis.

[Male osteoporosis]

BACKGROUND

Osteoporosis in men is an important public health problem with more than 1 million cases in Germany. Although osteoporotic fractures have a much higher mortality in men than in women, male patients are still underdiagnosed and undertreated.

OBJECTIVE

Epidemiology of male osteoporosis and current treatment situation, pathophysiological aspects at the hormonal level, risk factors, diagnostic work-up and therapeutic options.

MATERIAL AND METHODS

Overview of data concerning male osteoporosis, recommendations for diagnostic work-up and presentation of the study situation on pharmaceutical therapies.

RESULTS

As risk factors for osteoporosis are present in 50-70 % of male patients, a detailed patient history is necessary for assessment of the risk factors. Radiological imaging of the spine is primarily recommended to identify individuals with prevalent vertebral fractures, as approximately 10 % of males above the age of 50 years have suffered a vertebral fracture. Laboratory testing of relevant parameters helps to rule out other metabolic bone diseases. In Germany, specific medications available for the treatment of male osteoporosis comprise the active vitamin D analogue alfacalcidol, the oral bisphosphonates alendronate and risedronate, the intravenous biphosphonate zoledronic acid, the anti- receptor activator of NF-κB ligand (RANKL) antibody denosumab, which can be given as intravenous injection and strontium ranelate, a drug with a complex mode of action. Teriparatide, a recombinant form of the 34 N-terminal amino acid sequence of parathyroid hormone is the only anabolic agent approved for male osteoporosis.

CONCLUSION

Osteoporosis in men is increasingly being recognized as an important public health problem and affected patients need to be adequately diagnosed and treated. Nowadays, a broad spectrum of well-proven therapeutic options with different modes of action allow individual treatment strategies for male osteoporosis patients.

The clinical use of vitamin D metabolites and their potential developments: a position statement from the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) and the International Osteoporosis Foundation (IOF)

Several compounds are produced along the complex pathways of vitamin D3 metabolism, and synthetic analogs have been generated to improve kinetics and/or vitamin D receptor activation. These metabolites display different chemical properties with respect to the parental or native vitamin D3, i.e., cholecalciferol, which has been, so far, the supplement most employed in the treatment of vitamin D inadequacy. Hydrophilic properties of vitamin D3 derivatives facilitate their intestinal absorption and their manageability in the case of intoxication because of the shorter half-life. Calcidiol is a more hydrophilic compound than parental vitamin D3. Active vitamin D analogs, capable of binding the vitamin D receptor evoking vitamin D-related biological effects, are mandatorily employed in hypoparathyroidism and kidney failure with impaired 1α-hydroxylation. They have been shown to increase BMD, supposedly ameliorating calcium absorption and/or directly affecting bone cells, although their use in these conditions is jeopardized by the development of hypercalciuria and mild hypercalcemia. Further studies are needed to assess their overall safety and effectiveness in the long-term and new intermittent regimens, especially when combined with the most effective antifracture agents.

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

Eldecalcitol (1α,25-dihydroxy-2β-(3-hydroxypropoxy)vitamin D3, [developing code: ED-71]), a new osteoporosis treatment drug that was recently approved in Japan, is a best-in-class drug in the class of calcitriol (1α,25-dihydroxyvitamin D3) and its prodrug alfacalcidol (1α-hydroxyvitamin D3), which have been used to treat osteoporosis for 30 years. In a comparative Phase III clinical study with alfacalcidol in osteoporosis patients, eldecalcitol demonstrated superior efficacy in the endpoints of increment of bone mineral density and reduction of bone fracture with equivalent safety to alfacalcidol. Eldecalcitol was discovered by searching synthetic analogs of calcitriol and alfacalcidol, and its main structural characteristic is having the 3-hydroxypropoxy group at the 2β-position. This review discusses why introducing the group leads to excellent efficacy and safety in osteoporosis treatment and elucidates the functional roles of the 3-hydroxypropoxy group. Briefly, the functional roles of the group are, first, realizing the metabolism switching in which eldecalcitol shows resistance to CYP24A1 and is metabolized in the liver; second, increasing the affinity to the serum carrier protein and prolonging the half-life to 53h; and third, stabilizing the eldecalcitol-receptor complex. Taken together, these functional roles of the 3-hydroxypropoxy group are beneficial in osteoporosis treatment. This review attempts to give a detailed account of the mode of action of eldecalcitol by clarifying these multifunctional roles of the 3-hydroxypropoxy group from the medicinal chemist's perspective.