Abnormal microarchitecture and stiffness in postmenopausal women using chronic inhaled glucocorticoids

A Pilot Study of the Gut Microbiota in Spine Fusion Surgery Patients

Background

The microbiome has been identified as a contributor to bone quality. As skeletal health is critical to success of orthopedic surgery, the gut microbiome may be a modifiable factor associated with postoperative outcomes. For spine fusion surgery in particular, de novo bone formation and sufficient bone mineral density are essential for successful outcomes. Given the prevalence and complexity of these procedures, the identification of novel factors that may be related to operative success is important.

Questions/purposes

We sought to investigate how the composition of the microbiota related to bone health in a focused spinal fusion surgery cohort.

Methods

We investigated the composition of the microbiome in a cohort of 31 patients prior to spinal fusion surgery, as well as changes in the microbiome over 6 weeks postoperatively. Preoperative areal bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry.

Results

Composition of gut microbiota differed among spinal fusion patients with low bone mass (T-score ≤ -1.0) and those with normal BMD (P = .03). There was no significant change in composition of the gut microbiota between preoperative evaluation and 6 weeks postoperatively.

Conclusions

Our findings in this small sample suggest there may be a relationship between BMD and composition of the gut microbiome in patients who undergo spinal fusion surgery. Further work is needed to investigate these relationships as well as potential interventions to foster a favorable microbial composition in spinal fusion surgery patients.

Risk of fracture in women with glucocorticoid requiring diseases is independent from glucocorticoid use: An analysis on a nation-wide database

OBJECTIVE

Glucocorticoid-induced osteoporosis (GIOP) is a common cause of secondary osteoporosis. However, glucocorticoid requiring diseases pose a risk themselves for fracture. The aim of the present study was to determine the risk of fracture associated with variety of glucocorticoid requiring diseases independently from glucocorticoid use and other risk factors for osteoporosis.

METHODS

We conducted a retrospective cross-sectional analysis of a nation-wide cohort (DeFRACalc79 database). We used multivariable regression analysis adjusting for several risk factors for fracture and glucocorticoid intake to estimate the independent role of glucocorticoid requiring illnesses on fracture risk.

RESULTS

We found that patients with rheumatoid arthritis, connective tissue diseases, chronic obstructive pulmonary disease (COPD) and neurological diseases were at greater risk of vertebral or hip fracture (crude ORs 1.31, 1.20, 1.92 and 2.97 respectively). After adjusting for potential confounders COPD and neurological diseases remained significantly associated with an increased risk of vertebral or hip fractures (aORs 1.33, 95 % CI 1.18-1.49 and 2.43, 95 % CI 2.17-2.74). Rheumatoid arthritis, COPD, IBD and neurological diseases also significantly increased the risk of non-vertebral, non-hip fractures (aORs 1.23, 1.42, 1.52 and 1.94 respectively).

CONCLUSION

Some glucocorticoid requiring diseases were independently associated with an increased risk of fractures. COPD and neurological diseases with both vertebral and non-vertebral fracture risk while RA and IBD were independently associated only with non-vertebral, non-hip fractures.

Characterizing Bone Phenotypes Related to Skeletal Fragility Using Advanced Medical Imaging

PURPOSE OF REVIEW

Summarize the recent literature that investigates how advanced medical imaging has contributed to our understanding of skeletal phenotypes and fracture risk across the lifespan.

RECENT FINDINGS

Characterization of bone phenotypes on the macro-scale using advanced imaging has shown that while wide bones are generally stronger than narrow bones, they may be more susceptible to age-related declines in bone strength. On the micro-scale, HR-pQCT has been used to identify bone microarchitecture phenotypes that improve stratification of fracture risk based on phenotype-specific risk factors. Adolescence is a key phase for bone development, with distinct sex-specific growth patterns and significant within-sex bone property variability. However, longitudinal studies are needed to evaluate how early skeletal growth impacts adult bone phenotypes and fracture risk. Metabolic and rare bone diseases amplify fracture risk, but the interplay between bone phenotypes and disease remains unclear. Although bone phenotyping is a promising approach to improve fracture risk assessment, the clinical availability of advanced imaging is still limited. Consequently, alternative strategies for assessing and managing fracture risk include vertebral fracture assessment from clinically available medical imaging modalities/techniques or from fracture risk assessment tools based on clinical risk factors. Bone fragility is not solely determined by its density but by a combination of bone geometry, distribution of bone mass, microarchitecture, and the intrinsic material properties of bone tissue. As such, different individuals can exhibit distinct bone phenotypes, which may predispose them to be more vulnerable or resilient to certain perturbations that influence bone strength.

Prevention and Treatment of Glucocorticoid-Induced Osteoporosis in Adults: Consensus Recommendations From the Belgian Bone Club

Glucocorticoids are effective immunomodulatory drugs used for many inflammatory disorders as well as in transplant recipients. However, both iatrogenic and endogenous glucocorticoid excess are also associated with several side effects including an increased risk of osteoporosis and fractures. Glucocorticoid-induced osteoporosis (GIOP) is a common secondary cause of osteoporosis in adults. Despite availability of clear evidence and international guidelines for the prevention of GIOP, a large treatment gap remains. In this narrative review, the Belgian Bone Club (BBC) updates its 2006 consensus recommendations for the prevention and treatment of GIOP in adults. The pathophysiology of GIOP is multifactorial. The BBC strongly advises non-pharmacological measures including physical exercise, smoking cessation and avoidance of alcohol abuse in all adults at risk for osteoporosis. Glucocorticoids are associated with impaired intestinal calcium absorption; the BBC therefore strongly recommend sufficient calcium intake and avoidance of vitamin D deficiency. We recommend assessment of fracture risk, taking age, sex, menopausal status, prior fractures, glucocorticoid dose, other clinical risk factors and bone mineral density into account. Placebo-controlled randomized controlled trials have demonstrated the efficacy of alendronate, risedronate, zoledronate, denosumab and teriparatide in GIOP. We suggest monitoring by dual-energy X-ray absorptiometry (DXA) and vertebral fracture identification one year after glucocorticoid initiation. The trabecular bone score might be considered during DXA monitoring. Extended femur scans might be considered at the time of DXA imaging in glucocorticoid users on long-term (≥ 3 years) antiresorptive therapy. Bone turnover markers may be considered for monitoring treatment with anti-resorptive or osteoanabolic drugs in GIOP. Although the pathophysiology of solid organ and hematopoietic stem cell transplantation-induced osteoporosis extends beyond GIOP alone, the BBC recommends similar evaluation, prevention, treatment and follow-up principles in these patients. Efforts to close the treatment gap in GIOP and implement available effective fracture prevention strategies into clinical practice in primary, secondary and tertiary care are urgently needed.

Effect of Denosumab Compared With Risedronate on Bone Strength in Patients Initiating or Continuing Glucocorticoid Treatment

In a randomized clinical trial in patients initiating glucocorticoid therapy (GC-I) or on long-term therapy (GC-C), denosumab every 6 months increased spine and hip bone mineral density at 12 and 24 months significantly more than daily risedronate. The aim of this study was to evaluate the effects of denosumab compared with risedronate on bone strength and microarchitecture measured by high-resolution peripheral quantitative computed tomography (HR-pQCT) in GC-I and GC-C. A subset of 110 patients had high-resolution peripheral quantitative computed tomography (HR-pQCT) scans of the distal radius and tibia at baseline and at 12 and 24 months. Cortical and trabecular microarchitecture were assessed with standard analyses and failure load (FL) with micro-finite element analysis. At the radius at 24 months, FL remained unchanged with denosumab and significantly decreased with risedronate in GC-I (-4.1%, 95% confidence interval [CI] -6.4, -1.8) and, in GC-C, it significantly increased with denosumab (4.3%, 95% CI 2.1, 6.4) and remained unchanged with risedronate. Consequently, FL was significantly higher with denosumab than with risedronate in GC-I (5.6%, 95% CI 2.4, 8.7, p < 0.001) and in GC-C (4.1%, 95% CI 1.1, 7.2, p = 0.011). We also found significant differences between denosumab and risedronate in percentage changes in cortical and trabecular microarchitectural parameters in GC-I and GC-C. Similar results were found at the tibia. To conclude, this HR-pQCT study shows that denosumab is superior to risedronate in terms of preventing FL loss at the distal radius and tibia in GC-I and in increasing FL at the radius in GC-C, based on significant differences in changes in the cortical and trabecular bone compartments between treatment groups in GC-I and GC-C. These results suggest that denosumab could be a useful therapeutic option in patients initiating GC therapy or on long-term GC therapy and may contribute to treatment decisions in this patient population. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

The clinical application of high-resolution peripheral computed tomography (HR-pQCT) in adults: state of the art and future directions

High-resolution peripheral computed tomography (HR-pQCT) was developed to image bone microarchitecture in vivo at peripheral skeletal sites. Since the introduction of HR-pQCT in 2005, clinical research to gain insight into pathophysiology of skeletal fragility and to improve prediction of fractures has grown. Meanwhile, the second-generation HR-pQCT device has been introduced, allowing novel applications such as hand joint imaging, assessment of subchondral bone and cartilage thickness in the knee, and distal radius fracture healing. This article provides an overview of the current clinical applications and guidance on interpretation of results, as well as future directions. Specifically, we provide an overview of (1) the differences and reference data for HR-pQCT variables by age, sex, and race/ethnicity; (2) fracture risk prediction using HR-pQCT; (3) the ability to monitor response of anti-osteoporosis therapy with HR-pQCT; (4) the use of HR-pQCT in patients with metabolic bone disorders and diseases leading to secondary osteoporosis; and (5) novel applications of HR-pQCT imaging. Finally, we summarize the status of the application of HR-pQCT in clinical practice and discuss future directions. From the clinical perspective, there are both challenges and opportunities for more widespread use of HR-pQCT. Assessment of bone microarchitecture by HR-pQCT improves fracture prediction in mostly normal or osteopenic elderly subjects beyond DXA of the hip, but the added value is marginal. The prospects of HR-pQCT in clinical practice need further study with respect to medication effects, metabolic bone disorders, rare bone diseases, and other applications such as hand joint imaging and fracture healing. The mostly unexplored potential may be the differentiation of patients with only moderately low BMD but severe microstructural deterioration, which would have important implications for the decision on therapeutical interventions.

Age-dependent modulation of bone metabolism in zebrafish scales as new model of male osteoporosis in lower vertebrates

After middle age, in human bone, the resorption usually exceeds formation resulting in bone loss and increased risk of fractures in the aged population. Only few in vivo models in higher vertebrates are available for pathogenic and therapeutic studies about bone aging. Among these, male Danio rerio (zebrafish) can be successfully used as low vertebrate model to study degenerative alterations that affect the skeleton during aging, reducing the role of sex hormones.

In this paper, we investigated the early bone aging mechanisms in male zebrafish (3, 6, 9 months old) scales evaluating the physiological changes and the effects of prednisolone, a pro-osteoporotic drug.

The results evidentiated an age-dependent reduction of the mineralization rate in the fish scales, as highlighted by growing circle measurements. Indeed, the osteoblastic ALP activity at the matrix deposition site was found progressively downregulated.

The higher TRAP activity was found in 63% of 9-month-old fish scales associated with resorption lacunae along the scale border. Gene expression analysis evidentiated that an increase of the tnfrsf1b (homolog of human rank) in aging scales may be responsible for resorption stimulation.

Interestingly, prednisolone inhibited the physiological growth of the scale and induced in aged scales a more significant bone resorption compared with untreated fish (3.8% vs 1.02%). Bone markers analysis shown a significant reduction of ALP/TRAP ratio due to a prednisolone-dependent stimulation of tnfsf11 (homolog of human rankl) in scales of older fish.

The results evidentiated for the first time the presence of a senile male osteoporosis in lower vertebrate. This new model could be helpful to identify the early mechanisms of bone aging and new therapeutic strategies to prevent age-related bone alterations in humans.

Bone Evaluation by High-Resolution Peripheral Quantitative Computed Tomography in Patients With Adrenal Incidentaloma

CONTEXT

Data regarding high-resolution peripheral quantitative computed tomography (HR-pQCT) in patients with adrenal incidentaloma (AI) are unknown.

PURPOSE

To evaluate the areal bone mineral density (aBMD), microstructure, and fractures in patients with nonfunctioning AI (NFAI) and autonomous cortisol secretion (ACS).

METHODS

We evaluated 45 patients with NFAI (1 mg dexamethasone suppression test [DST] ≤1.8 µg/dL) and 30 patients with ACS (1 mg DST 1.9-5.0 µg/dL). aBMD was measured using dual-energy X-ray absorptiometry; vertebral fracture by spine X-ray; and bone geometry, volumetric bone mineral density (vBMD), and microstructure by HR-pQCT.

RESULTS

Patients with ACS showed lower aBMD values at the spine, femoral neck, and radius 33% than those with NFAI. Osteoporosis was frequent in both groups: NFAI (64.9%) and ACS (75%). Parameters at the distal radius by HR-pQCT were decreased in patients with ACS compared to those with NFAI: trabecular vBMD (Tb.vBMD, P = 0.03), inner zone of the trabecular region (Inn.Tb.vBMD, P = 0.01), the bone volume/tissue volume ratio (BV/TV, P = 0.03) and trabecular thickness (P = 0.04). As consequence, a higher ratio of the outer zone of the trabecular region/inner zone vBMD (Meta/Inn.vBMD, P = 0.003) was observed. A correlation between the cortisol levels after 1 mg DST and Meta/Inn.vBMD ratio was found (r = 0.29; P = 0.01). The fracture frequency was 73.7% in patients with ACS vs 55.6% in patients with NFAI (P = 0.24).

CONCLUSION

Our findings point to an association between trabecular bone microarchitectural derangement at the distal radius and ACS. Our data suggest that AI have a negative impact on bone when assessed by HR-pQCT, probably associated to subclinical hypercortisolism.

Glucocorticoid-induced osteoporosis update

PURPOSE OF REVIEW

Steroid-induced osteoporosis or glucocorticoid-induced osteoporosis (GIOP) is a common form of secondary osteoporosis and is a cause of increased morbidity and mortality. The pathogenesis of GIOP includes decreased bone formation and increased bone resorption. Clinicians can rely on several effective medications for the treatment and prevention of GIOP, including antiresorptive drugs (i.e. bisphosphonates) and bone anabolic drugs (i.e. teriparatide).

RECENT FINDINGS

Recent studies have further highlighted that GIOP is a major public health concern and have provided new insights on the pathogenesis of GIOP, in particular, the dose-dependent effects of glucocorticoids on bone. New evidence on the real-world effectiveness of established GIOP therapies have been recently published as well as the results of the 24-months denosumab randomized controlled trial in GIOP.

SUMMARY

GIOP and fragility fractures are important adverse events related to the long-term use of glucocorticoids. Recent studies have provided additional data on the epidemiology and pathogenesis of GIOP and on the efficacy and effectiveness of GIOP therapies.

The effects of bone metabolism in different methylprednisolone pulse treatments for Graves' ophthalmopathy

The aim of the present study was to analyze the effects of methylprednisolone pulse therapy (MPPT) courses on bone metabolism in patients with Graves' ophthalmopathy (GO). A retrospective analysis of 45 patients with moderate-to-severe active GO who received 1 or 2 courses of MPPT was performed. Of these, 16 patients underwent 2 courses of treatment. Bone metabolic markers and the density of the lumbar spine (L1-4), femoral neck and total hip were measured using a dual-energy X-ray bone density instrument, and the differences in bone metabolism prior to and after treatment were determined for each group and compared. The results indicated that serum I collagen N-terminal peptide (P1NP) and serum β-collagen crosslinked C-terminal peptide (CTX) were markedly decreased after the first pulse of treatment. In those patients who received a second course of MPPT, CTX levels were significantly decreased, but P1NP was not significantly different from the baseline value. CTX and P1NP levels remained unchanged between the first and second course of MPPT; similarly, there were no changes from baseline in 25(OH) vitamin D3 and bone mineral density after the first and second course of MPPT. However, the level of 25(OH) vitamin D3 was significantly elevated after the second course compared with the first course. In conclusion, the side effects of MPPT on bone metabolism were marginal and a second course of MPPT did not worsen bone metabolism. These MPPT regimens may therefore be considered to be a safe and effective treatment option for patients with moderate-to-severe active GO.

Isomeric flavonoid aglycones derived from Epimedii Folium exerted different intensities in anti-osteoporosis through OPG/RANKL protein targets

Two Epimedium-derived isomeric flavonoids, CIT and IT, had the therapeutic effect in osteopenic rats. However, it is difficult to expound their activity differences in anti-osteoporosis. This paper contrasted their anti-osteoporosis activity from the perspective of their affinity to OPG/RANKL protein targets. Molecular docking indicated that both of CIT and IT could interact with the hydrophobic pockets of OPG/RANKL, while CIT was easier and more stable to combine with RANKL. On the contrary, compared with CIT, IT was more inclined to combine with OPG and stay away from combining with RANKL. Subsequently, whether the interaction between isomeric flavonoids and OPG/RANKL targets promoted or suppressed bone resorption was undefined and which was validated by zebrafish embryo and ovariectomized rats in this paper. Compared with IT, the staining area and cumulative optical density of zebrafish skeleton were significantly increased after the treatment of CIT (0.1 μM, p < 0.05). Furthermore, CIT mainly reflected a more significant role in upregulating OPG (p < 0.05), downregulating RANKL (p < 0.05), reducing serum AKP and TRACP level (p < 0.05), enhancing bone biomechanical properties (p < 0.05), increasing bone mineral density (p < 0.05) and improving trabecular bone microarchitecture (p < 0.05) in osteoporotic rats. In conclusion, the combination of isomeric flavonoids (CIT/IT) and OPG/RANKL targets attenuated the excitation effects of OPG or RANKL on RANKL. Because CIT was more firmly combined with RANKL than IT, CIT had stronger anti-osteoporosis effect by inhibiting bone resorption.