Maintenance low dose systemic glucocorticoids have limited impact on bone strength and mineral density among incident renal allograft recipients: A pilot prospective cohort study

Evaluating Osteoporosis in Chronic Kidney Disease: Both Bone Quantity and Quality Matter

Bone strength is determined not only by bone quantity [bone mineral density (BMD)] but also by bone quality, including matrix composition, collagen fiber arrangement, microarchitecture, geometry, mineralization, and bone turnover, among others. These aspects influence elasticity, the load-bearing and repair capacity of bone, and microcrack propagation and are thus key to fractures and their avoidance. In chronic kidney disease (CKD)-associated osteoporosis, factors traditionally associated with a lower bone mass (advanced age or hypogonadism) often coexist with non-traditional factors specific to CKD (uremic toxins or renal osteodystrophy, among others), which will have an impact on bone quality. The gold standard for measuring BMD is dual-energy X-ray absorptiometry, which is widely accepted in the general population and is also capable of predicting fracture risk in CKD. Nevertheless, a significant number of fractures occur in the absence of densitometric World Health Organization (WHO) criteria for osteoporosis, suggesting that methods that also evaluate bone quality need to be considered in order to achieve a comprehensive assessment of fracture risk. The techniques for measuring bone quality are limited by their high cost or invasive nature, which has prevented their implementation in clinical practice. A bone biopsy, high-resolution peripheral quantitative computed tomography, and impact microindentation are some of the methods established to assess bone quality. Herein, we review the current evidence in the literature with the aim of exploring the factors that affect both bone quality and bone quantity in CKD and describing available techniques to assess them.

Effects of Dual-Release Hydrocortisone on Bone Metabolism in Primary and Secondary Adrenal Insufficiency: A 6-Year Study

Context

Patients with primary (PAI) and secondary adrenal insufficiency (SAI) experience bone metabolism alterations, possibly due to excessive replacement. Dual-release hydrocortisone (DR-HC) has shown promising effects on several parameters, but bone metabolism has seldom been investigated.

Objective

We evaluated the long-term effects of once-daily DR-HC on bone in PAI and SAI.

Methods

Patients on immediate-release glucocorticoid therapy were evaluated before and up to 6 years (range, 4-6) after switching to equivalent doses of DR-HC, yielding data on bone turnover markers, femoral and lumbar spine bone mineral density (BMD), and trabecular bone score (TBS).

Results

Thirty-two patients (19 PAI, 18 female), median age 52 years (39.4-60.7), were included. At baseline, osteopenia was observed in 38% of patients and osteoporosis in 9%, while TBS was at least partially degraded in 41.4%. Higher body surface area-adjusted glucocorticoid doses predicted worse neck (P < .001) and total hip BMD (P < .001). Longitudinal analysis showed no significant change in BMD. TBS showed a trend toward decrease (P = .090). Bone markers were stable, albeit osteocalcin levels significantly varied. PAI and SAI subgroups behaved similarly, as did patients switching from hydrocortisone or cortisone acetate. Compared with men, women exhibited worse decline in TBS (P = .017) and a similar trend for neck BMD (P = .053).

Conclusion

After 6 years of chronic DR-HC replacement, BMD and bone markers remained stable. TBS decline is more likely due to an age-related derangement of bone microarchitecture rather than a glucocorticoid effect. Our data confirm the safety of DR-HC replacement on bone health in both PAI and SAI patients.

Pharmacological History of Missing Subjects: Perspective of a Correction Factor to Aid in the Study of Bone Remains

Simple Summary

The reconstruction of the biological profile of skeletal remains of missing subjects is also based on the analysis of the quality of bone tissue. The density of bone mass is a factor that allows us to inscribe the subject in a specific age group. Bone density varies not only according to age but also by the intake of certain drugs and certain abuse substances. The objective of our study is to propose the introduction of pharmacological history in the profile of missing persons. Information on drugs or abuse substances taken by the missing person is a useful corrective factor for tracing the chronological age of bone remains found, increasing the likelihood of identification. We emphasize the usefulness of this information also for the characterization of bone injuries and for the dating of antemortem fractures, useful elements to trace the cause and dynamics of death. The evaluation of these findings is also based on the characteristics of the bone tissue of skeletal remains which is also affected by any drugs and/or substances of abuse. Therefore, we believe that the pharmacological history of the missing subjects could be a new and interesting tool to help the activity of the forensic anthropologist.

Abstract

In forensic anthropology, bone mineral density and the estimation of the dating of fractures based on the degree of progress of healing processes are important parameters of study on bone remains. With our article we aim, on the one hand, to highlight the importance that these parameters have in the reconstruction of the biological profile of the subject, as well as the time and the cause of death; on the other hand, we aim to limit their variability according to the medical substances and/or abuse assumed during life by the subject. The aim of this article is to encourage the introduction of the pharmacological history of missing persons as a new correction factor for the study of bone remains, possibly based on new scientific studies that allow us to establish with greater specificity the effect that certain pharmacological therapies produce on bone mass and the speed of remodeling.

Current status of glucocorticoid usage in solid organ transplantation

Glucocorticoids (GCs) have been the mainstay of immunosuppressive therapy in solid organ transplantation (SOT) for decades, due to their potent effects on innate immunity and tissue protective effects. However, some SOT centers are reluctant to administer GCs long-term because of the various related side effects. This review summarizes the advantages and disadvantages of GCs in SOT. PubMed and Scopus databases were searched from 2011 to April 2021 using search syntaxes covering “transplantation” and “glucocorticoids”. GCs are used in transplant recipients, transplant donors, and organ perfusate solution to improve transplant outcomes. In SOT recipients, GCs are administered as induction and maintenance immunosuppressive therapy. GCs are also the cornerstone to treat acute antibody- and T-cell-mediated rejections. Addition of GCs to organ perfusate solution and pretreatment of transplant donors with GCs are recommended by some guidelines and protocols, to reduce ischemia-reperfusion injury peri-transplant. GCs with low bioavailability and high potency for GC receptors, such as budesonide, nanoparticle-mediated targeted delivery of GCs to specific organs, and combination use of dexamethasone with inducers of immune-regulatory cells, are new methods of GC application in SOT patients to reduce side effects or induce immune-tolerance instead of immunosuppression. Various side effects involving different non-targeted organs/tissues, such as bone, cardiovascular, neuromuscular, skin and gastrointestinal tract, have been noted for GCs. There are also potential drug-drug interactions for GCs in SOT patients.

Changes in bone microarchitecture following parathyroidectomy in patients with secondary hyperparathyroidism

Background

Secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD) has a significant effect on bone, affecting both trabecular and cortical compartments. Although parathyroidectomy results in biochemical improvement in mineral metabolism, changes in bone microarchitecture as evaluated by high-resolution imaging modalities are not known. Magnetic resonance imaging (MRI) provides in-depth three-dimensional assessment of bone microarchitecture, as well as determination of mechanical bone strength determined by finite element analysis (FEA).

Methods

We conducted a single-centre longitudinal study to evaluate changes in bone microarchitecture with MRI in patients with SHPT undergoing parathyroidectomy. MRI was performed at the distal tibia at baseline (time of parathyroidectomy) and at least 12 months following surgery. Trabecular and cortical topological parameters as well as bone mechanical competence using FEA were assessed.

Results

Fifteen patients with CKD (12 male, 3 female) underwent both MRI scans at the time of surgery and at least 12 months post-surgery. At baseline, 13 patients were on dialysis, one had a functioning kidney transplant, and one was pre-dialysis with stage 5 CKD. Seven patients received a kidney transplant following parathyroidectomy prior to follow-up MRI. MRI parameters in patients at follow up were consistent with loss in trabecular and cortical bone thickness (p = 0.006 and 0.03 respectively). Patients who underwent a kidney transplant in the follow-up period had reduction in trabecular thickness (p = 0.05), whereas those who continued on dialysis had reduction in cortical thickness (p = 0.04) and mechanical bone strength on FEA (p = 0.03).

Conclusion

Patients with severe SHPT requiring parathyroidectomy have persistent changes in bone microarchitecture at least 12 months following surgery with evidence of ongoing decline in trabecular and cortical thickness.

Glucocorticoids and Trabecular Bone Score

TBS (Trabecular Bone Score) is the latest tool for clinicians to evaluate bone micro-architecture based on a pixel greyscale, which is provided by lumbar dual-energy X-ray absorptiometry (DXA). Its use enhances fracture prediction in addition to DXA-BMD (Bone Mineral Density). This is independent of fracture risk assessment (FRAX) and DXA results. We present a narrative review regarding the connection between TBS and Glucocorticoids (GC), either as a drug used for different conditions or as a tumor-produced endogenous excess.

TBS is a better discriminator for GC-induced vertebral fractures compared to DXA-BMD. This aspect is similarly available for patients with osteoporosis diagnosed by DXA. TBS is inversely correlated with the cumulative dose of GC (systemic or inhaled), with disease duration, and positively correlated with respiratory function in patients with asthma. Low TBS values are found in females with a T-score at the hip within the osteoporosis range, with diabetes mellitus, or who use GC. Lumbar TBS is a screening tool in menopausal women with type 2 diabetes mellitus. TBS is an independent parameter that provides information regarding skeleton deterioration in diabetic patients receiving GC therapy in a manner complementary to DXA-BMD. TBS might become an essential step regarding the adrenalectomy decision in patients with adrenal incidentaloma in whom autonomous cortisol secretion might damage bone micro-architecture. TBS currently represents a standard tool of fracture risk evaluation in patients receiving GC therapy or with endogenous Cushing’s syndrome, a tool easy to be applied by different practitioners since GCs are largely used

Added Value of Impact Microindentation in the Evaluation of Bone Fragility: A Systematic Review of the Literature

The current gold standard for the diagnosis of osteoporosis and the prediction of fracture risk is the measurement of bone mineral density (BMD) using dual energy x-ray absorptiometry (DXA). A low BMD is clearly associated with increased fracture risk, but BMD is not the only determinant of bone strength, particularly in secondary osteoporosis and metabolic bone disorders in which components other than BMD are affected and DXA often underestimates true fracture risk. Material properties of bone which significantly contribute to bone strength have become evaluable in vivo with the impact microindentation (IMI) technique using the OsteoProbe® device. The question arises whether this new tool is of added value in the evaluation of bone fragility. To this effect, we conducted a systematic review of all clinical studies using IMI in vivo in humans also addressing practical aspects of the technique and differences in study design, which may impact outcome. Search data generated 38 studies showing that IMI can identify patients with primary osteoporosis and fractures, patients with secondary osteoporosis due to various underlying systemic disorders, and scarce longitudinal data also show that this tool can detect changes in bone material strength index (BMSi), following bone-modifying therapy including use of corticosteroids. However, this main outcome parameter was not always concordant between studies. This systematic review also identified a number of factors that impact on BMSi outcome. These include subject- and disease-related factors such as the relationship between BMSi and age, geographical region and the presence of fractures, and technique- and operator-related factors. Taken together, findings from this systematic review confirm the added value of IMI for the evaluation and follow-up of elements of bone fragility, particularly in secondary osteoporosis. Notwithstanding, the high variability of BMSi outcome between studies calls for age-dependent reference values, and for the harmonization of study protocols. Prospective multicenter trials using standard operating procedures are required to establish the value of IMI in the prediction of future fracture risk, before this technique is introduced in routine clinical practice.

Drugs Causing Bone Loss

Drugs may cause bone loss by lowering sex steroid levels (e.g., aromatase inhibitors in breast cancer, GnRH agonists in prostate cancer, or depot medroxyprogestone acetate - DMPA), interfere with vitamin D levels (liver inducing anti-epileptic drugs), or directly by toxic effects on bone cells (chemotherapy, phenytoin, or thiazolidinedions, which diverts mesenchymal stem cells from forming osteoblasts to forming adipocytes). However, besides effects on the mineralized matrix, interactions with collagen and other parts of the unmineralized matrix may decrease bone biomechanical competence in a manner that may not correlate with bone mineral density (BMD) measured by dual energy absorptiometry (DXA).Some drugs and drug classes may decrease BMD like the thiazolidinediones and consequently increase fracture risk. Other drugs such as glucocorticoids may decrease BMD, and thus increase fracture risk. However, glucocorticoids may also interfere with the unmineralized matrix leading to an increase in fracture risk, not mirrored in BMD changes. Some drugs such as selective serotonin reuptake inhibitors (SSRI), paracetamol, and non-steroidal anti-inflammatory drugs (NSAIDs) may not per se be associated with bone loss, but fracture risk may be increased, possibly stemming from an increased risk of falls stemming from effects on postural balance mediated by effects on the central nervous system or cardiovascular system.This paper performs a systematic review of drugs inducing bone loss or associated with fracture risk. The chapter is organized by the Anatomical Therapeutic Chemical (ATC) classification.