Vitamin D and Calcium Addition during Denosumab Therapy over a Period of Four Years Significantly Improves Lumbar Bone Mineral Density in Japanese Osteoporosis Patients

Position Statement: Vitamin D Intake to Prevent Osteoporosis and Fracture in Adults

Adequate vitamin D status is essential for bone health. New randomized controlled trials investigating the effect of vitamin D supplementation on bone health have recently been published. This position statement updates and expands on the previous 2015 position statement of the Korean Society for Bone and Mineral Research on the adequate vitamin D status for healthy older adults (age ≥ 70 years) and those at high risk of osteoporosis and fracture (adults on osteoporosis medications) to maintain serum 25-hydroxy-vitamin D (25[OH]D) levels ≥ 20 ng/mL but < 50 ng/mL. A serum 25(OH)D level of 30 ng/mL may be beneficial for those on anti-resorptives. Vitamin D can be obtained from ultraviolet light exposure and diet. To reach the target vitamin D status through intake, adults must consume at least 400 IU/day to reach 20 ng/mL and 800 to 1,000 IU/day to reach 30 ng/mL. Foods familiar to the Korean diet that are high in vitamin D content or consumed frequently enough to positively impact vitamin D status are introduced in addition to the amount required to help reach one's target vitamin D status.

Osteoporosis treatment by mesenchymal stromal/stem cells and their exosomes: Emphasis on signaling pathways and mechanisms

Osteoporosis is the loss of bone density, which is one of the main problems in developed and developing countries and is more common in the elderly. Because this disease is often not diagnosed until a bone fracture, it can become a life-threatening disease and cause hospitalization. With the increase of older people in a population, this disease's personal and social costs increase year by year and affect different communities. Most current treatments focus on pain relief and usually do not lead to bone tissue recovery and regeneration. But today, the use of stem cell therapy is recommended to treat and improve this disease recovery, which helps restore bone tissue by improving the imbalance in the osteoblast-osteoclast axis. Due to mesenchymal stromal/stem cells (MSCs) characteristics and their exosomes, these cells and vesicles are excellent sources for treating and preventing the progression and improvement of osteoporosis. Due to the ability of MSCs to differentiate into different cells and migrate to the site of injury, these cells are used in tissue regenerative medicine. Also, due to their contents, the exosomes of these cells help regenerate and treat various tissue injuries by affecting the injury site's cells. In this article, we attempted to review new studies in which MSCs and their exosomes were used to treat osteoporosis.

A bibliometric research based on hotspots and frontier trends of denosumab

Denosumab is a monoclonal antibody that targets and inhibits the osteoclast activating factor receptor activator for nuclear factor-κB ligand (RANKL). It has been widely used in the treatment of osteoporosis, giant cell tumors of bone, and in the prevention of malignant skeletal-related events (SREs). We collected the research results and related MeSH terms of denosumab from 2011 to 2021 through the Web of Science and PubMed, respectively. The literature was visualized and analyzed by CiteSpace and bibliometric online analysis platforms. The MeSH terms were biclustered using the Bibliographic Co-Occurrence Analysis System (BICOMB) and graph clustering toolkit (gCLUTO). The results show that the number of denosumab-related annual publications had increased from 51 to 215, with the United States leading and Amgen Inc. being the most influential in the past 10 years. Articles published in the Journal of Bone and Mineral Research had the highest total citations. Three scholars from Shinshu University in Matsumoto, Yukio Nakamura, Takako Suzuki, and Hiroyuki Kato, joined the field relatively late but produced the most. The clinical comparison and combination of denosumab with other drugs in the treatment of osteoporosis was the most significant focus of research. Drug withdrawal rebound and management strategies have gained more attention and controversy recently. MeSH analysis revealed eight major categories of research hotspots. Among them, exploring the multiple roles of the RANK-RANKL-OPG system in tumor progression, metastasis, and other diseases is the potential direction of future mechanism research. It is a valuable surgical topic to optimize the perioperative drug administration strategy for internal spinal fixation and orthopedic prosthesis implantation. Taken together, the advantages of denosumab were broad and cost-effective. However, there were still problems such as osteonecrosis of the jaw, severe hypocalcemia, a high recurrence rate of giant cells in the treatment of bone and individual sarcoidosis, and atypical femoral fractures, which need to be adequately solved.

Near-Infrared Light-Controlled and Real-Time Detection of Osteogenic Differentiation in Mesenchymal Stem Cells by Upconversion Nanoparticles for Osteoporosis Therapy

Osteoporosis (OP) is one of the most common diseases in the elderly, and it is not effectively solved by current treatments. Mesenchymal stem cells (MSCs) have multiple differentiation potentials, which can induce osteogenic differentiation to treat OP; however, it is important to understand how to remotely control and detect osteogenic differentiation in vivo in real time. Here, we developed an upconversion nanoparticle (UCNP)-based photoresponsive nanoplatform for near-infrared (NIR) light-mediated control of intracellular icariin (ICA) release to regulate the osteogenic differentiation of MSCs for OP therapy. We simultaneously detected osteogenic differentiation in vivo in real time to evaluate the treatment effects. The Tm/Er-doped UCNPs were synthesized and coated with mesoporous silica (UCNP@mSiO₂) first. Then, the photocaged linker 4-(hydroxymethyl)-3-nitrobenzoic acid (ONA) and the PEG linker (OH-PEG4-MAL) were linked to the surface of UCNP@mSiO₂ to conjugate to the cap β-cyclodextrin (β-CD) and the Arg-Gly-Asp (RGD)-targeted peptide/matrix metalloproteinase 13 (MMP13)-sensitive peptide-BHQ (CGPLGVRGK-BHQ₃) to form the UCNP nanoplatform (UCNP@mSiO₂-peptide-BHQ-ONA-CD) for drug loading. Under 980 nm NIR light, the upconverted UV from the UCNPs triggered the cleavage of cap β-CD and the intracellular release of ICA to induce the osteogenic differentiation of MSCs for OP therapy. Meanwhile, MMP13, which was produced by osteogenic differentiation of MSCs, cleaved the MMP13-sensitive peptide to remove BHQ and recover the fluorescence of UCNPs, allowing real-time detection of osteogenic differentiation and the evaluation of the OP treatment effect. This photoresponsive UCNP nanoplatform has the potential to be used for the remote control and real-time detection of osteogenic differentiation of MSCs for OP therapy by NIR.

Semaphorin3A promotes osseointegration of titanium implants in osteoporotic rabbits

OBJECTIVE

In the present study, we intend to assess the function of Sema3A in osteointegration of titanium implants both in vivo and in vitro.

MATERIAL AND METHODS

Briefly, Sema3A was transfected in HBMSCs cells to detect its effect on osteogenesis. Subsequently, an in vivo rabbit model was established. Eighteen female rabbits were randomly assigned into three groups (n=6), and rabbits in the two treatment groups (OVX groups) were subjected to bilateral ovariectomy, while those in the control group were treated with sham operation. Twelve weeks later, we first examined expression levels of Sema3A in rabbits of the three groups. Titanium implants were implanted in rabbit proximal tibia. Specifically, rabbits in sham group were implanted with Matrigel, while the remaining in the OVX experimental group (OVX+Sema3A group) and OVX group were implanted with Matrigel containing Sema3A adeno-associated virus or empty vector, respectively.

RESULTS

Histomorphometry results uncovered that rabbits in the OVX+Sema3A group had a significantly higher BIC compared with those of the OVX group on the 12th week of post-implantation. And compared with the OVX group, the maximum push-out force increased by 89.4%, and the stiffness increased by 39.4%, the toughness increased by 63.8% in the OVX+Sema3A group at 12 weeks.

CONCLUSION

Sema3A has a positive effect on promoting early osseointegration of titanium implants in osteoporotic rabbits.

CLINICAL RELEVANCE

Our research found that Sema3A can improve the osteogenic ability of bone marrow stem cells and promotes osseointegration during osteoporosis.

Effects and Mechanism of Zishen Jiangtang Pill on Diabetic Osteoporosis Rats Based on Proteomic Analysis

Objective

To explore the effect and mechanism of ZJP on DOP rats by proteomic analysis.

Materials and Methods

After the establishment of diabetes model by Streptozocin (STZ, 60 mg/kg), 40 Wistar rats were equally divided into normal group, model group (diabetic rats), high-dose group (3.0 g/kg/d ZJP), and low-dose group (1.5 g/kg/d ZJP) and received treatment for 3 months. Histological changes in bone and pancreas tissues were observed by hematoxylin and eosin staining, electron microscopy, and immunofluorescence. Proteomic and bioinformatic analyses were performed to identify the differentially expressed proteins. The fingerprint and active ingredients of ZJP were identified via high-performance liquid chromatography (HPLC).

Results

Compared with the model group, ZJP could rescue the weight, fasting blood glucose, and fasting insulin of rats in both high-dose and low-dose group. ZJP could also improve the microstructures of pancreatic islet cells, bone mass, and trabecular and marrow cavities in DOP rats. Bioinformatic analysis suggested that ZJP might influence DOP via multiple pathways, mainly including ribosomes, vitamin digestion and absorption, and fat digestion and absorption. The primary active ingredients, including notoginsenoside R1, ginsenoside Rg1, ginsenoside Re, icariin, and ginsenoside Rb1, were detected.

Conclusion

ZJP could significantly improve the histomorphology and ultrastructure of bone and islets tissues and might serve as an effective alternative medicine for the treatment of DOP.

Advances in mesenchymal stem cell transplantation for the treatment of osteoporosis

Osteoporosis is a systemic metabolic bone disease with characteristics of bone loss and microstructural degeneration. The personal and societal costs of osteoporosis are increasing year by year as the ageing of population, posing challenges to public health care. Homing disorders, impaired capability of osteogenic differentiation, senescence of mesenchymal stem cells (MSCs), an imbalanced microenvironment, and disordered immunoregulation play important roles during the pathogenesis of osteoporosis. The MSC transplantation promises to increase osteoblast differentiation and block osteoclast activation, and to rebalance bone formation and resorption. Preclinical investigations on MSC transplantation in the osteoporosis treatment provide evidences of enhancing osteogenic differentiation, increasing bone mineral density, and halting the deterioration of osteoporosis. Meanwhile, the latest techniques, such as gene modification, targeted modification and co-transplantation, are promising approaches to enhance the therapeutic effect and efficacy of MSCs. In addition, clinical trials of MSC therapy to treat osteoporosis are underway, which will fill the gap of clinical data. Although MSCs tend to be effective to treat osteoporosis, the urgent issues of safety, transplant efficiency and standardization of the manufacturing process have to be settled. Moreover, a comprehensive evaluation of clinical trials, including safety and efficacy, is still needed as an important basis for clinical translation.

The vitamin D and calcium controversy: an update

PURPOSE OF REVIEW

Calcium and vitamin D supplementation is widely recommended for prevention of falls and fracture, particularly in the elderly where calcium intakes and vitamin D levels are often inadequate. A number of meta-analyses have questioned the benefits of untargeted or 'holistic' supplementation for falls and fracture, and raised the possibility of adverse cardiovascular effects. This review provides an update on these controversies.

RECENT FINDINGS

Recent advances have largely centred around new trials of vitamin D and meta-analyses of published trials and observational studies. These articles have identified holistic vitamin D supplementation with or without calcium is unlikely to be an effective primary prevention strategy for falls or fracture. There has also been high-quality evidence that vitamin D, daily or as a bolus, does not reduce the risk of cardiovascular events.

SUMMARY

The benefits of vitamin D and calcium supplements for holistic fall and fracture prevention remain uncertain. Recent evidence supports the concept that high-dose vitamin D has adverse musculoskeletal effects. Future studies should focus on moderate daily doses. Finally, there remain inconsistent findings for adverse cardiovascular effects of calcium supplements with or without vitamin D. This uncertainty should be taken into account when evaluating the risk/benefits of supplementation.