Clinical applications of RANK-ligand inhibition

Osteoporosis Complications in Crohn's Disease Patients: Factors, Pathogenesis, and Treatment Outlines

The causes of osteoporosis in Crohn’s disease (CD) are multifactorial; cytokines, steroids, and vitamin deficiency all have an essential role. It is imperative to distinguish the factors that contribute to bone resorption, potentially increasing the risk of low bone mineral density (BMD), osteoporosis, and fracture. However, the pathogenicity of osteoporosis associated with CD remains unclear. Although osteoporosis treatment may vary between bisphosphonate and corticosteroid, infliximab's efficacy, when combined with immune modulators, suppresses both CD symptoms and osteoporosis progression. In this review, we aim to understand the present pathogenicity of osteoporosis, including the factors pro-inflammatory cytokines, chronic steroid use, and malnutrition, developing osteoporosis in a different pathological way, and to assist the treatment lines implying a positive outcome of osteoporosis in CD patients.

Osteoporosis is considered to be one of the early complications of CD where early detection can prevent osteoporosis progression. This can be done by utilizing dual-energy X-ray-absorptiometry (DEXA) to evaluate the Z-score and treat the existing factors that have a role in the progression of osteoporosis in CD patients.

Dental care for patients taking antiresorptive drugs: a literature review

Antiresorptive drugs (ARDs), such as bisphosphonates or denosumab, that prevent bone resorption are widely used in patients with osteoporosis or with cancer that has metastasized to the bones. Although osteonecrosis of the jaw (ONJ) is a well-documented complication of ARD use, the benefits ARDs outweigh the complication. Thus, research has focused on finding ways to prevent or reduce the risk of developing ONJ. Dentists, as part of a multi-professional team, have a critical role in preventing ONJ. However, many dentists tend to hesitate to provide dental care to patients with ONJ, or tend to think that it is a problem to be dealt with by oral surgeons. This review gives an overview of ARD-related ONJ and provides the guidelines for dental care in patients taking ARDs to lower the risk of developing ONJ.

Association between Mycobacterium avium complex lung disease and serum vitamin D status, antimicrobial peptide levels, and bone mineral density

Vitamin D maintains calcium balance and has immunomodulatory effects. Only few studies have revealed the relationship between vitamin D and its associated factors in Mycobacterium avium complex (MAC) infection. This study aimed to investigate the effects of MAC infection on serum vitamin D, human cationic antimicrobial protein 18, its C-terminal 37 amino acid fragment (hCAP18/LL-37) levels, and bone mineral density (BMD).We enrolled 58 patients with MAC lung disease and 15 control participants. Serum 25-hydroxyvitamin D and hCAP18/LL-37 levels were measured via enzyme-linked immunosorbent assay. Lastly, computed tomography scan density readings of the BMD of the thoracic and lumbar vertebral bones (Th4, Th7, Th10, and L1) were assessed.No significant differences in patient characteristics and serum vitamin D levels were observed. Patients with MAC lung disease had significantly low serum hCAP18/LL-37 levels (P = .049). Moreover, low BMD of the mean thoracic and lumbar vertebrae was observed (mean Th, P = .012; L1, P = .48, respectively). A higher prevalence of scoliosis (P = .031) was observed in the participants with low BMD compared with the control participants. Based on a multivariate analysis, patients with MAC lung disease had significantly lower body mass index [odds ratio (OR), 19.1; 95% confidence interval (CI), 2.0-419.0; P < .01] and vertebral BMD (OR, 12.4; 95% CI, 1.7-160.6; P = .012) than control participants.Serum hCAP18/LL-37 level and BMD were significantly decreased in patients with MAC lung disease without relation to serum vitamin D level. The vitamin D-independent pathway might affect the waning of antimicrobial peptides and decrease in BMD.

Molecular Pathogenesis and Diagnostic Imaging of Metastatic Jaw Tumors

Metastasis is the spread of malignant cells from a primary tumor to distant sites through lymphatics or blood vessels. Malignant lesions metastasizing to the oral and perioral region are a rarity indeed. Malignant lesions could metastasize to both soft tissue of oral cavity and the hard tissues of the jaws and recent meta-analysis showed that metastasis is more common in the jaws than oral soft tissues because of rich vascular supply. The incidence is very low when compared to the incidence of primary oral cancers; nevertheless, one has to include in the diagnostic workup, metastatic malignant lesions, when an irregular ill-defined radiolucency or radiodensity with ragged edges in noted. It could be a challenging task for a diagnostician, in cases with the presence and location of the primary tumor is unknown. Advanced oral imaging technologies and biochemical markers play a vital role in diagnosing such lesions.

Association of Respiratory Tuberculosis with Incident Bone Fracture: Bridging the Tuberculosis Airway Infection and the Osteoporotic Bone

Objective

The relationship between respiratory tuberculosis (RT) and incident fragility fracture and osteoporosis/fragility fracture in the general population is not well determined; therefore, we conducted a nationwide cohort study to investigate this relationship.

Methods

We used the National Health Insurance Research Database of Taiwan to identify 6612 newly diagnosed patients with RT (RT cohort) and 13220 patients without RT (non-RT cohort) from 1999 to 2005. The mean durations of follow-up were (6.73 ± 4.00 years, 8.11 ± 3.24 years) in the (RT cohort, non- RT cohort); respectively. The occurrence of incident fragility fracture and osteoporosis/fragility fracture were followed up until the end of 2011. The adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) and 98% CIs of incident fragility fracture and osteoporosis/fragility fracture were estimated using the multivariable Cox proportional hazard model after adjusting for age, sex, occupation, drug use, and comorbidities.

Results

A Cox proportional hazards regression analysis was performed and showed the aHRs of [incident fragility fracture; osteoporosis/fragility fracture] were [1.69 (95% CI = 1.26–2.28, 98% CI = 1.18–2.44); 1.42 (95% CI = 1.25–1.61, 98% CI = 1.21–1.65)] between the RT and non-RT cohorts. Regarding the sex, the aHRs of the [incident fragility fracture; osteoporosis / fragility fracture] were [1.57 (98% CI = 1.10–2.23, 98% CI = 1.02–2.41); 1.15 (95% CI = 0.97–1.36, 98% CI = 0.94–1.41)] in the men. The aHRs of the RT cohort without oral steroid use in the [incident fragility fracture; osteoporosis / fragility fracture] were [1.87 (95% CI = 1.20–2.90, 98% CI = 1.09–3.19); 1.41 (95% CI = 1.19–1.67, 98% CI = 1.14–1.74)].

Conclusion

The RT associated with the incident fragility fracture, either in men or absence of oral steroid use.

Assessment of off-label use of denosumab 60 mg injection during the early postmarketing period using health insurance claims data

Off-label use of denosumab 60 milligram (mg) injection was assessed within an administrative claims database. The completeness of claims to assess off-label use was investigated with medical record review. Potential denosumab 60 mg off-label use was observed based on claims, but many had evidence of on-label indications based on medical record review.

INTRODUCTION

Denosumab 60 mg injection is approved in the USA to treat patients at high fracture risk due to postmenopausal osteoporosis, male osteoporosis, and hormone therapy for the treatment of prostate and breast cancers. Its RANK ligand-inhibiting effect makes it a candidate for the off-label treatment of other conditions mediated by the rate of bone resorption by osteoclasts. To better understand its utilization patterns, we assessed off-label use of denosumab 60 mg within an administrative claims database.

METHODS

Definite, probable, and possible denosumab 60 mg users were identified during the early postmarketing period within a claims database of a US healthcare insurer. Medical record review confirmed a sample of these users. Off-label use among definite and probable users and all chart-confirmed users was classified using claims-derived age, dose interval, and diagnosis and treatment received relative to the administration date. Among chart-confirmed users classified as off-label, patient characteristics related to treatment indication were abstracted from medical records to investigate the completeness of claims to study off-label medication use.

RESULTS

Off-label use was identified based on claims in approximately 25 % of definite and probable denosumab 60 mg users and 35 % of chart-confirmed users. Medical record review identified evidence of on-label indications in 81 % of chart-confirmed users classified as off-label in claims.

CONCLUSIONS

Many of the off-label denosumab 60 mg users had diagnoses or treatment consistent with on-label indications based on medical record review, suggesting these are under-recorded in claims data. It is warranted to be cautious when using administrative databases to assess off-label medication use.

OPG-Fc but Not Zoledronic Acid Discontinuation Reverses Osteonecrosis of the Jaws (ONJ) in Mice

Osteonecrosis of the jaws (ONJ) is a significant complication of antiresorptive medications, such as bisphosphonates and denosumab. Antiresorptive discontinuation to promote healing of ONJ lesions remains highly controversial and understudied. Here, we investigated whether antiresorptive discontinuation alters ONJ features in mice, employing the potent bisphosphonate zoledronic acid (ZA) or the receptor activator of NF-κB ligand (RANKL) inhibitor OPG-Fc, utilizing previously published ONJ animal models. Mice were treated with vehicle (veh), ZA, or OPG-Fc for 11 weeks to induce ONJ, and antiresorptives were discontinued for 6 or 10 weeks. Maxillae and mandibles were examined by μCT imaging and histologically. ONJ features in ZA and OPG-Fc groups included periosteal bone deposition, empty osteocyte lacunae, osteonecrotic areas, and bone exposure, each of which substantially resolved 10 weeks after discontinuing OPG-Fc but not ZA. Full recovery of tartrate-resistant acid phosphatase-positive (TRAP+) osteoclast numbers occurred after discontinuing OPG-Fc but not ZA. Our data provide the first experimental evidence demonstrating that discontinuation of a RANKL inhibitor, but not a bisphosphonate, reverses features of osteonecrosis in mice. It remains unclear whether antiresorptive discontinuation increases the risk of skeletal-related events in patients with bone metastases or fracture risk in osteoporosis patients, but these preclinical data may nonetheless help to inform discussions on the rationale for a "drug holiday" in managing the ONJ patient.

Detection of rankl positive cells in gingival tissue in healthy & chronic periodontal disease patients-a comparative study

Aim & Objective: The receptor activator of NF-kappa B ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG), are the important proteins implicated in osteoclastogenesis. This study aimed to identify & quantify RANKL positive cells in gingival tissues in healthy & diseased patients & the study looks for immunohistochemical evidence of the expression of the protein in gingival tissue samples.

MATERIALS AND METHODS

Patients were randomly selected. Thirty subject each for (test & control). Age range of 25-55y, either sex was selected. Tissue samples were collected from Control - Healthy Gingiva & Test-Chronic Periodontitis Patients. Tissue sections were prepared. An Immunohistochemical analysis was done & cell counting was done for RANKL positive cells.

RESULTS

Immunohistochemical staining showed that RANKL-positive cells were significantly distributed in the inflammatory epithelium & connective tissue zone of diseased & non-diseased gingiva. RANKL, positive cells was increased significantly in patients with chronic periodontitis (p < 0.05).

CONCLUSION

These findings imply that in this comparative study of gingival tissue for, RANKL positive cells, these cells were present in both healthy & chronic periodontitis samples, but number of positive cells present is significantly increased in chronic periodontitis.

Osteoprotegerin and kidney disease

Vascular calcification in chronic kidney disease (CKD) patients is associated to increased mortality. Osteoprotegerin (OPG) is a soluble tumor necrosis factor (TNF) superfamily receptor that inhibits the actions of the cytokines receptor activator of nuclear factor kappa-B ligand (RANKL) and TNF-related apoptosis-inducing ligand (TRAIL) by preventing their binding to signaling receptors in the cell membrane. OPG-deficient mice display vascular calcification while OPG prevented calcification of cultured vascular smooth muscle cells and protected kidney cells from TRAIL-induced death. OPG may be a biomarker in patients with kidney disease. Circulating OPG is increased in predialysis, dialysis and transplant CKD patients and may predict vascular calcification progression and patient survival. By contrast, circulating OPG is decreased in nephrotic syndrome. In addition, free and exosome-bound urinary OPG is increased in human kidney disease. Increased urinary OPG has been associated with lupus nephritis activity. Despite the association of high OPG levels with disease, experimental functional information available suggests that OPG might be protective in kidney disease and in vascular injury in the context of uremia. Thus, tissue injury results in increased OPG, while OPG may protect from tissue injury. Recombinant OPG was safe in phase I randomized controlled trials. Further research is needed to fully define the therapeutic and biomarker potential of OPG in patients with kidney disease.

The use of gene therapy vs. corticotomy surgery in accelerating orthodontic tooth movement

OBJECTIVE

Alveolar corticotomy surgery is an adjunctive therapy for reducing orthodontic treatment duration. The activation pathways of bone resorption involved in the tooth movement (TM) process are directly linked to the receptor activator of the nuclear factor-kB ligand (RANKL). Whether similar molecular pathways through RANKL, are shared by the acceleratory TM process (corticotomy-induced or not), sustained acceleration would therefore be expected with transgenic overexpression of this factor. We hypothesize that maintaining transgenic overexpression of RANKL will accelerate TM under force over time rather than at the beginning of therapy only; this contrasts with the corticotomy procedure.

MATERIAL AND METHODS

We transfected the pcDNA3.1(+)-mRANKL transgene in vitro into NIH3T3 cells, then evaluated by PCR, Western blot and ex vivo resorption assay. Quantification of RANKL immunofluorescence, fluorescence-based tartrate-resistant acid phosphatase+ (TRAP+) osteoclast counts and histological analyses of the bone resorption area were performed and clinically correlated after a 32-day in vivo experiment comparing corticotomy and gene therapy.

RESULTS

In vitro experiments resulted in increased level of RANKL protein (46%, p<0.05) and greater mineral resorption (39%, p<0.05) compared to the controls. In vivo results showed increased RANKL immunoexpression for both corticotomy (twofold) and transfection groups (threefold) after 10 days. After 32 days, a similar result was obtained for the transfected group but not for the surgery group. These data correlate with the clinical effect of decelerating TM in the surgery group.

CONCLUSIONS

Selective gene therapy with RANKL has been experimentally tested as an alternative method to corticotomy surgery, showing higher effectiveness than surgical methods used for acceleratory purposes in orthodontics.

A short account of metastatic bone disease

In adults, bone is the preferential target site for metastases from primary cancers of prostate, breast, lungs and thyroid. The tendency of these cancers to metastasize to bone is determined by the anatomical distribution of the blood vessels, by the genetic profile of the cancer cells and by the biological characteristics of the bone microenvironment that favour the growth of metastatic cells of certain cancers.Metastases to bone may have either an osteolytic or an ostoblastic phenotype. The interaction in the bone microenvironment between biological factors secreted by metastatic cells, and by osteoblasts and osteoclasts, and the osteolytic and osteoblastic factors released from the organic matrix mediate a vicious cycle characterized by metastatic growth and by ongoing progressive bone destruction. This interaction determines the phenotype of the metastatic bone disease.

Emerging strategies and therapies for treatment of Paget's disease of bone

Paget's disease of bone (PDB) is a progressive monostotic or polyostotic metabolic bone disease characterized by focal abnormal bone remodeling, with increased bone resorption and excessive, disorganized, new bone formation. PDB rarely occurs before middle age, and it is the second most frequent metabolic bone disorder after osteoporosis, affecting up to 3% of adults over 55 years of age. One of the most striking and intriguing clinical features is the focal nature of the disorder, in that once the disease is established within a bone, there is only local spread within that bone and no systemic dissemination. Despite many years of intense research, the etiology of PDB has still to be conclusively determined. Based on a detailed review of genetic and viral factors incriminated in PDB, we propose a unifying hypothesis from which we can suggest emerging strategies and therapies. PDB results in weakened bone strength and abnormal bone architecture, leading to pain, deformity or, depending on the bone involved, fracture in the affected bone. The diagnostic assessment includes serum total alkaline phosphatase, total body bone scintigraphy, skull and enlarged view pelvis x-rays, and if needed, additional x-rays. The ideal therapeutic option would eliminate bone pain, normalize serum total alkaline phosphatase with prolonged remission, heal radiographic osteolytic lesions, restore normal lamellar bone, and prevent recurrence and complications. With the development of increasingly potent bisphosphonates, culminating in the introduction of a single intravenous infusion of zoledronic acid 5 mg, these goals of treatment are close to being achieved, together with long-term remission in almost all patients. Based on the recent pathophysiological findings, emerging strategies and therapies are reviewed: ie, pulse treatment with zoledronic acid; denosumab, a fully human monoclonal antibody directed against RANK ligand; tocilizumab, an interleukin-6 receptor inhibitor; odanacatib, a cathepsin K inhibitor; and proteasome and Dickkopf-1 inhibitors.

Advances in the understanding of mineral and bone metabolism in inflammatory bowel diseases

Chronic inflammatory disorders such as inflammatory bowel diseases (IBDs) affect bone metabolism and are frequently associated with the presence of osteopenia, osteoporosis, and increased risk of fractures. Although several mechanisms may contribute to skeletal abnormalities in IBD patients, inflammation and inflammatory mediators such as TNF, IL-1β, and IL-6 may be the most critical. It is not clear whether the changes in bone metabolism leading to decreased mineral density are the result of decreased bone formation, increased bone resorption, or both, with varying results reported in experimental models of IBD and in pediatric and adult IBD patients. New data, including our own, challenge the conventional views, and contributes to the unraveling of an increasingly complex network of interactions leading to the inflammation-associated bone loss. Since nutritional interventions (dietary calcium and vitamin D supplementation) are of limited efficacy in IBD patients, understanding the pathophysiology of osteopenia and osteoporosis in Crohn's disease and ulcerative colitis is critical for the correct choice of available treatments or the development of new targeted therapies. In this review, we discuss current concepts explaining the effects of inflammation, inflammatory mediators and their signaling effectors on calcium and phosphate homeostasis, osteoblast and osteoclast function, and the potential limitations of vitamin D used as an immunomodulator and anabolic hormone in IBD.