GLUCOCORTICOID-INDUCED BONE DISEASE: MECHANISMS AND IMPORTANCE IN PEDIATRIC PRACTICE

Alleviation of Glucocorticoid-Induced Osteoporosis in Rats by Ethanolic Reynoutria multiflora (Thunb.) Moldenke Extract

Secondary osteoporosis is frequently due to the use of high-dose glucocorticoids (GCs). The existing strategy for managing glucocorticoid-induced osteoporosis (GIOP) is considered insufficient and remains in a state of ongoing evolution. Therefore, it is crucial to develop more precise and effective agents for the treatment of GIOP. The constituents of Reynoutria multiflora (Thunb.) Moldenke, specifically Polygonum multiflorum (PM) Thunb, have previously shown promise in mitigating osteopenia. This study aimed to investigate the therapeutic effects of an ethanolic PM extract (PMR30) against GIOP in male rats. Prednisone (6 mg/kg/day, GC) was continuously administered to rats to induce GIOP, and they were subjected to treatment with or without ethanolic PMR30 for a duration of 120 days. Serum was collected for biochemical marker analysis. Bone histomorphometric, histological, and TUNEL analyses were performed on tibia samples. The protein expressions of LC3, Agt5, and Beclin 1 in the femur underwent examination through western blotting. Prolonged and excessive GC treatment significantly impeded bone formation, concomitant with reduced bone mass and body weight. It also suppressed OCN and OPG/RANKL in serum, and decreased Beclin 1 and LC3 in bone. Simultaneously, there was an elevation in bone resorption markers and apoptosis. Treatments with both high dose and low dose of PMR30 alleviated GIOP, stimulated bone formation, and upregulated OCN and OPG/RANKL, while suppressing TRACP-5b, CTX-I, and apoptosis. The impact of PMR30 possibly involves the enhancement of autophagy proteins (LC3, Agt5, and Beclin 1) and the inhibition of apoptosis within the bone. PMR30 holds promise as a prospective therapeutic agent for preventing and treating GIOP.

Low bone mineral density in Thai children with systemic lupus erythematosus: prevalence and risk factors

Background

Improvement of disease recognition and management has increased the survival of children with systemic lupus erythematosus (SLE), but has shifted the morbidity focus toward long-term complications, such as low bone mass and osteoporosis. Studies in adults with SLE show older age, chronic inflammation, and corticosteroid therapy are risk factors for low bone mineral density (BMD) and osteoporosis.

Objectives

To determine the prevalence of and identify risk factors associated with low BMD in Thai children with SLE.

Methods

We conducted a retrospective review of demographic data and clinical variables for a cohort of 60 Thai children with SLE who underwent 2 dual-energy X-ray absorptiometry (DXA) at their initial examination and later follow-up. We considered a BMD z score ≤ -2.0 to indicate low BMD. Binary logistic regression was used to assess risk factors potentially associated with low BMD.

Results

The prevalence of low BMD at the first visit was 40% and increased to 55% over follow-up. We found a significantly decreased hip BMD z score (median difference -0.25, 95% confidence interval [CI] -0.40 to -0.05; P = 0.016) and lumbar BMD z score (median difference -0.49, 95% CI -0.69 to -0.28; P < 0.001) over time. The cumulative steroid dose tended to be higher for patients with low BMD (adjusted odds ratio [OR] = 1.08, 95% CI 1.00 to 1.17; P = 0.050).

Conclusion

Low BMD has a 40% prevalence in Thai children newly diagnosed with SLE and progresses significantly over time. Higher cumulative corticosteroid dose tended to be associated with a low BMD, but we did not find a significant risk in this small sample.

Alendronate Improves Bone Mineral Density in Children and Adolescents Perinatally Infected With Human Immunodeficiency Virus With Low Bone Mineral Density for Age

BACKGROUND

Children and adolescents with perinatal human immunodeficiency virus (HIV) infection and with low bone mineral density (BMD) may be at higher risk of osteoporosis and fractures in later life than their uninfected peers. Bisphosphonate therapy has been shown to reduce fractures in adults with osteoporosis, but has not been formally studied in youths living with HIV.

METHODS

Fifty-two children and adolescents (aged 11-24 years) perinatally infected with HIV with low lumbar spine (LS) BMD (Z score < -1.5) were randomized to receive once-weekly alendronate or placebo in a double-blind cross-over study designed to assess the safety and efficacy of 48 and 96 weeks of alendronate in the United States and Brazil. All participants received daily calcium carbonate and vitamin D supplementation and were asked to engage in regular weight-bearing exercise. Safety and efficacy are summarized for the initial 48 weeks of the trial.

RESULTS

Grade 3 or higher abnormal laboratory values, signs, or symptoms developed in 5 of 32 (16%) participants on alendronate and 2 of 18 (11%) on placebo (P > .99). No cases of jaw osteonecrosis, atrial fibrillation, or nonhealing fractures were reported. Mean increases (95% confidence interval) in LS BMD over 48 weeks were significantly larger on alendronate (20% [14%-25%]) than placebo (7% [5%-9%]) (P < .001). Similar improvements were seen for whole body BMD.

CONCLUSIONS

In this small study in children and adolescents perinatally infected with HIV with low LS BMD, 48 weeks of alendronate was well-tolerated, showed no safety concerns, and significantly improved LS and whole body BMD compared to participants on vitamin D/calcium supplementation and exercise alone.

CLINICAL TRIALS REGISTRATION

NCT00921557.

Glucocorticoid transiently upregulates mitochondrial biogenesis in the osteoblast

Glucocorticoid (GC)-induced bone loss is the most prevalent form of secondary osteoporosis. Previous studies demonstrated that long-term incubation of dexamethasone (DEX) induced oxidative stress and mitochondrial dysfunctions, consequently leading to apoptosis of differentiated osteoblasts. This DEX-induced cell death might be the main causes of bone loss. We previously described that DEX induced biphasic mitochondrial alternations. As GC affects mitochondrial physiology through several different possible routes, the short-term and long-term effects of GC treatment on mitochondria in the osteoblast have not been carefully characterized. Here, we examined the expression levels of genes that are associated with mitochondrial functions at several different time points after incubation with DEX. Mitochondrial biogenesis-mediated genes nuclear respiratory factor 1 (Nrf1) and Nrf2 were upregulated after 4-h incubation, and then declined after 24-h incubation, suggesting that mitochondrial biogenesis were transiently upregulated by DEX. In contrast, mitochondrial fusion gene optic atrophy 1 (Opa1) and mitofusin 2 (Mfn2) started to be elevated as the biogenesis started to decrease. Finally, the mitochondrial fission increased and apoptosis becomes prominent. Agree with the mitochondrial biphasic alterations hypothesis, the results suggested an early increase of mitochondrial activities and biogenesis upon DEX stimulation to the osteoblasts. The oxidative phosphorylation and inducible nitric oxide synthase levels increased results in oxidative stress accumulation, leading to mitochondrial fusion, and subsequently fission and triggering the apoptosis. Our results indicated that the primary effects of GC on mitochondria are promoting their functions and biogenesis. Mitochondrial breakdown and the activation of the apoptotic pathways appeared to be the secondary effect after long-term treatment.

Immune Markers and Their Association with Bone Density in Children, Adolescents, and Young Adults with Perinatally Acquired HIV

To describe distributions of immune markers in children and young adults by sex and HIV status, and within groups, investigate associations of immune markers with bone density across Tanner stage. Using data and samples from 353 participants in a cross-sectional study in youth with perinatally acquired HIV (PHIV) and matched HIV-negative controls, distributions of inflammation and activation immune markers were described by sex and HIV status. Correlations and structural equation models (SEM) were used to explore marginal and multivariable associations of the immune markers with bone density and to assess whether patterns of association varied by sex and HIV status. Immune marker distributions did not differ by sex, but there were some differences by HIV status. Correlation patterns among bone, body composition, and immune markers were similar across the sex and HIV status groups. Conclusions from SEMs were limited by small sample sizes, but there was some indication that patterns of association between bone density and certain immune markers differed in male PHIV with more advanced Tanner stage compared to the other three groups. In conclusion, distributions of bone density, body composition, and immune markers may vary by sex and HIV status, although associations among these outcomes within sex and HIV status groups appear similar. Bone density of male PHIV appears to be more negatively affected than females, regardless of female HIV status. Larger longitudinal studies across Tanner stages are needed to further explore potential biological relationships between immune markers and bone density in youth living with HIV.

Prevalence and Predictors of Compromised Bone Mineral Density in Pediatric Eosinophilic Esophagitis

OBJECTIVES

The aim of the study was to determine whether patients with eosinophilic esophagitis (EoE) have lower bone mineral density (BMD) than expected and if bone deficits are more pronounced in subgroups of patients according to comorbidities (atopic disease and joint hypermobility) or treatments (dietary restriction, medication exposure).

STUDY DESIGN

Retrospective chart review was performed to obtain clinical data, including length of diagnosis, comorbidities, and methods of treatment for patients with EoE ages 3 to 21 years who had a lumbar spine dual-energy x-ray absorptiometry scan performed between 2014 and 2017. BMD was standardized by calculation of age, sex, and race-specific z scores.

RESULTS

A total of 269 patients met study criteria. The mean BMD z score (-0.55, 95% confidence interval: -0.68, -0.42) was lower than expected (P < 0.0001), and the prevalence of low BMD z score (≤-2.0) was higher than expected (8.5%, 95% confidence interval: 5.2%-11.9%, P < 0.0001). In multivariable regression models, BMD z scores were -0.27 lower among those following an elimination diet and -0.65 lower among those with any lifetime use of a proton pump inhibitor (93% of the sample). There was no association with swallowed steroid use.

CONCLUSIONS

In our sample, pediatric patients with EoE had a slightly lower BMD z score compared to peers, and the prevalence of low BMD was higher than expected. Taken cautiously given the limitations of our sample, risk factors for bone deficits included any lifetime use of proton pump inhibitor and a restrictive elimination diet, but not swallowed steroid use. Larger prospective studies are needed to better characterize risk factors for low BMD to help inform screening, selection of therapies, and provide appropriate anticipatory guidance for patients with EoE.

Central Giant Cell Granuloma Treated with Intralesional Corticosteroid Injections and Bisphosphonates: A Long-Term Follow-Up Case Study

Central giant cell granuloma (CGCG) is a benign intraosseous lesion of the head and neck with potential for aggressive and locally destructive behaviour. Lesions of the maxilla tend to expand more than those of the mandible due to the thinner cortices and spongy tissue of this location. Surgical removal is the most common treatment; however, it may be disfiguring in aggressive cases, especially for lesions located in the maxilla. Alternative treatments, such as intralesional corticosteroid injections, have been performed with satisfactory results. We report a case of a 12-year-old female patient with a CGCG of the left maxilla that was treated with 40 doses of intralesional triamcinolone acetonide infiltrations combined with alendronate sodium and calcium carbonate. Clinical and imaging follow-up over 12 years demonstrates improvement in the patient's condition.