Citations

Abstract Background: Adrenal adenoma is reported in around 5% of adults undergoing cross-sectional imaging. Although most adenomas are considered non-functioning (NFAT), up to 48% present with mild autonomous cortisol secretion (MACS). Several studies reported increased prevalence and incidence of vertebral fractures in MACS; however conclusions are limited by small sample size, selection bias, inadequate reference population and length of follow up. Objective: To determine the prevalence and incidence of site-specific fragility fractures in a population-based cohort of patients with adrenal adenomas. Methods: Residents of local community with a radiographic diagnosis of adrenal adenoma between 1995 and 2017 were identified using a centralized epidemiologic database and matched with reference subjects for sex and age. All subjects were followed through 2017, until death or migration from the community. MACS was diagnosed based on cortisol level ≥1.8 mcg/dl after overnight 1mg dexamethasone suppression, NFAT based on cortisol level <1.8 mcg/dl, and patients not tested with dexamethasone were considered as adenoma with unknown cortisol secretion (AUCS). Results: Of 1003 patients with adrenal adenomas (581 women (58%), median age of diagnosis 63 years (20–96)), 136 (14%) were diagnosed with NFAT, 86 (9%) with MACS, and 781(78%) with AUCS. At the time of diagnosis, patients had higher BMI (median 30 vs 28 kg/m2, p<0.001), and higher prevalence of tobacco use (70% vs 54%, p<0.001) than reference subjects. Of 154 patients and 113 reference subjects with BMD available at baseline, patients had a higher median BMD at the total hips (0.93 vs 0.89, p=0.02) but similar median BMD at lumbar spine (1.05 vs 1.03, p=0.49) when compared to reference subjects. However, patients had a higher prevalence of fractures than reference subjects (any fracture: 50% vs 42%, p<0.001, vertebral fracture: 6.5% vs 3.7%, P=0.004). When adjusted for age, sex, and prior history of fracture, patients with adenoma had HR of 1.24 (CI 95% 1.04–1.48) for developing a new fracture and HR of 1.18 (CI 95% 0.97–1.44) when also adjusted for BMI and smoking. Subgroup analysis demonstrated that the prevalence of fractures at the time of diagnosis was higher in all 3 subgroups at any fragility fracture site when compared to reference subjects (NFAT: 44% vs 37%, MACS: 48% vs 43%, AUCS: 51% vs 43%); patients with MACS had the highest incidence of new fracture after 5 years of follow up when compared to AUCS and NFAT (cumulative incidence: MACS 25% vs NFAT 19% vs AUCS 16%), though the differences were not significant. Conclusions: Patients with adrenal adenomas have higher prevalence of fractures at the time of diagnosis. During follow up, patients with adenoma have a higher incidence of fractures even when adjusted for sex, age, and prior history of fracture, possibly due to underlying undiagnosed abnormal cortisol secretion.

Abstract Patients with Type 2 Diabetes (T2D) are at higher fracture risk despite having relatively normal or even increased BMD by DXA. Increased cortical porosity has emerged as a potential factor contributing to fragility fractures in T2D. However, there is conflicting evidence whether T2D patients have increased cortical porosity. We hypothesized that microvascular complications have an important role in cortical porosity. Thus, we performed high-resolution peripheral quantitative computed tomography imaging at the distal radius and tibia to evaluate bone microarchitecture in men with T2DM age ≥ 50 yrs or postmenopausal women with T2DM and nondiabetic controls. Comprehensive diabetic complications were assessed in all patients including urine microalbuminuria, retinopathy, neuropathy (touch, temperature, and vibration sensation), ankle brachial index (ABI) and transcutaneous oxygen tension (TcPO2). Percent differences between groups were obtained from linear regression models adjusting for age, BMI, and sex. Relationships between variables were assessed using adjusted Spearman correlations. A total of 164 T2D patients (mean age 68.9 ±7.8 yrs.; 56.7% men; HbA1C=7.7 ±0.9%; mean diabetes duration 15.2 yrs.) and 107 nondiabetic controls (mean age 67.3±8.8 yrs.; 42.1% men; HbA1C =5.4 ±0.3%) were recruited to the study. Overall, there was a trend for increased cortical porosity at the distal tibia in the T2D group (+12.2%; p=0.063) compared with nondiabetic controls. Of note, TcPO2 was negatively correlated with cortical porosity at the distal radius (r= -0.17; p= 0.039) and distal tibia (r= -0.15; p= 0.073). In particular, the Low TcPO2 (≤40 mmHg) group (n=29) had greater cortical porosity at the distal tibia (+19.6 %; p=0.037) compared with the High TcPO2 (>40 mmHg) group (n=133). In addition, the low TcPO2 group had a significant increase in cortical porosity in the distal tibia (+24.8% p=0.020) compared with nondiabetic controls. In conclusion, this is the first evidence in humans indicating that TcPO2, a measure of microvascular blood flow, is linked to cortical porosity in the distal radius and tibia in T2D patients. Our findings may explain the conflicting findings regarding cortical porosity in T2D because only T2D patients with impaired microvascular blood flow have increased cortical porosity. Collectively, our data indicate that cortical porosity is a microvascular complication of longstanding T2D.

Abstract Patients with Type 2 Diabetes (T2D) are at increased fracture risk despite having relatively normal or even increased BMD by DXA. The critical aspect of bone quality deterioration in T2D patients could explain this clinically important discrepancy. Material composition is a component of bone quality that has emerged as a potential factor contributing to fragility fractures in T2D patients. However, there is sparse evidence regarding whether T2D patients have decreased bone material properties compared with non-diabetic controls. We hypothesized that increased production of advanced glycation endproducts (AGEs) has an important role in reducing bone material strength in patients with and without diabetes. Thus, we used the OsteoProbe®, a bone microindentation device that provides an index of cortical bone material properties (Bone Material Strength index – BMSi) in men with T2D age ≥ 50 yrs or postmenopausal women with T2D and nondiabetic controls. We also utilized a non-invasive measure of skin AGEs (AGE Reader®) to evaluate AGEs accumulation through skin autofluorescence. Linear regression models were used to assess group differences with and without adjusting for age, Body Mass Index (BMI), and sex. Relationships between variables were assessed using adjusted Pearson correlations. A total of 152 T2D patients (mean age 68.5 ±7.6 yrs.; 59.2% men; HbA1C=7.7 ±1.0%; mean diabetes duration 15.5 yrs.) and 105 non-diabetic controls (mean age 67.2±8.8 yrs.; 41.0% men; HbA1C =5.4 ±0.3%) were recruited to the study. Overall, there was no difference in BMSi between T2DM and control subjects: unadjusted (p= 0.636); adjusted (p= 0.695). However, skin AGEs were negatively correlated with BMSi (r= -0.23, p <0.001). In subgroup analyses, skin AGEs were also negatively associated with BMSi in both T2DM (r= -0.23, p=0.004) and control (r= -0.21, p=0.033) subjects. In conclusion, these findings demonstrate that a higher burden of AGEs is associated with worse bone quality. Our findings may explain the conflicting findings regarding reductions in BMSi in T2D because only T2D patients with a high level of AGEs accumulation have impaired BMSi. Moreover, the association of skin AGEs with BMSi in non-diabetic subjects emphasizes the important role of AGEs in decreasing bone quality and potentially contributing to fracture risk. Collectively, our data indicate that non-invasive skin AGEs measurement could be used as a tool to evaluate bone quality in patients with T2D as well as in the non-diabetic population.

The worldwide prevalence of type 2 diabetes (T2D) is increasing. Despite normal to higher bone density, patients with T2D paradoxically have elevated fracture risk resulting, in part, from poor bone quality. Advanced glycation endproducts (AGEs) and inflammation as a consequence of enhanced receptor for AGE (RAGE) signaling are hypothesized culprits, although the exact mechanisms underlying skeletal dysfunction in T2D are unclear. Lack of inducible models that permit environmental (in obesity) and temporal (after skeletal maturity) control of T2D onset has hampered progress. Here, we show in C57BL/6 mice that a onetime pharmacological intervention (streptozotocin, STZ) initiated in adulthood combined with high-fat diet–induced (HFD-induced) obesity caused hallmark features of human adult-onset T2D, including prolonged hyperglycemia, insulin resistance, and pancreatic β cell dysfunction, but not complete destruction. In addition, HFD/STZ (i.e., T2D) resulted in several changes in bone quality that closely mirror those observed in humans, including compromised bone microarchitecture, reduced biomechanical strength, impaired bone material properties, altered bone turnover, and elevated levels of the AGE CML in bone and blood. Furthermore, T2D led to the premature accumulation of senescent osteocytes with a unique proinflammatory signature. These findings highlight the RAGE pathway and senescent cells as potential targets to treat diabetic skeletal fragility.

Abstract Osteoporosis-related fractures are undertreated, due in part to misinformation about recommended approaches to patient care and discrepancies among treatment guidelines. To help bridge this gap and improve patient outcomes, the American Society for Bone and Mineral Research assembled a multistakeholder coalition to develop clinical recommendations for the optimal prevention of secondary fractureamong people aged 65 years and older with a hip or vertebral fracture. The coalition developed 13 recommendations (7 primary and 6 secondary) strongly supported by the empirical literature. The coalition recommends increased communication with patients regarding fracture risk, mortality and morbidity outcomes, and fracture risk reduction. Risk assessment (including fall history) should occur at regular intervals with referral to physical and/or occupational therapy as appropriate. Oral, intravenous, andsubcutaneous pharmacotherapies are efficaciousandcanreduce risk of future fracture.Patientsneededucation,however, about thebenefitsandrisks of both treatment and not receiving treatment. Oral bisphosphonates alendronate and risedronate are first-line options and are generally well tolerated; otherwise, intravenous zoledronic acid and subcutaneous denosumab can be considered. Anabolic agents are expensive butmay be beneficial for selected patients at high risk.Optimal duration of pharmacotherapy is unknown but because the risk for second fractures is highest in the earlypost-fractureperiod,prompt treatment is recommended.Adequate dietary or supplemental vitaminDand calciumintake shouldbe assured. Individuals beingtreatedfor osteoporosis shouldbe reevaluated for fracture risk routinely, includingvia patienteducationabout osteoporosisandfracturesandmonitoringfor adverse treatment effects.Patients shouldbestronglyencouraged to avoid tobacco, consume alcohol inmoderation atmost, and engage in regular exercise and fall prevention strategies. Finally, referral to endocrinologists or other osteoporosis specialists may be warranted for individuals who experience repeated fracture or bone loss and those with complicating comorbidities (eg, hyperparathyroidism, chronic kidney disease).©2019American Society for Bone andMineral Research.

Abstract Context Several studies have reported increased risk of fragility fractures in patients with mild autonomous cortisol secretion (MACS), discordant to the degree of bone density deterioration. Objective To evaluate the effect of MACS on bone metabolism in patients with adrenal adenomas. Design Cross-sectional study with prospective enrollment, 2014-2019 Setting Referral center. Patients 213 patients with adrenal adenomas: 22 Cushing syndrome (CS), 92 MACS and 99 nonfunctioning adrenal tumors (NFAT). Main Outcome Measures Osteocalcin, procollagen I intact N-terminal (PINP), C-terminal telopeptide (CTX), sclerostin. Results Patients with CS demonstrated lower markers of bone formation compared with patients with MACS and NFAT (CS vs MACS vs NFAT: mean osteocalcin 14.8 vs 20.1 vs 21.3 ng/mL [P < 0.0001]; mean PINP 34.8 vs 48.7 vs 48.5 µg/L [P = 0.003]). Severity of cortisol excess was inversely associated with sclerostin (CS vs MACS vs NFAT: mean sclerostin 419 vs 538 vs 624 ng/L, [P < 0.0001]). In a multivariable model of age, sex, body mass index, cortisol, and bone turnover markers, sclerostin was a significant predictor of low bone mass in patients with MACS (OR 0.63 [CI 95%, 0.40–0.98] for each 100 ng/L of sclerostin increase). After adrenalectomy, osteocalcin, CTX, and sclerostin increased by a mean difference of 6.3 ng/mL, 0.12 ng/mL, and 171 pg/mL (P = 0.02 for all), respectively. Conclusions Lower sclerostin level in patients with MACS reflects a reduction in osteocyte function or number associated with exposure to chronic cortisol excess. Increase in bone turnover markers after adrenalectomy suggests restoration of favorable bone metabolism.

ABSTRACT Clinical radiotherapy treats life-threatening cancers, but the radiation often affects neighboring normal tissues including bone. Acute effects of ionizing radiation include oxidative stress, DNA damage, and cellular apoptosis. We show in this study that a large proportion of bone marrow cells, osteoblasts, and matrix-embedded osteocytes recover from these insults only to attain a senescent profile. Bone analyses of senescence-associated genes, senescence-associated beta-galactosidase (SA-β-gal) activity, and presence of telomere dysfunction-induced foci (TIF) at 1, 7, 14, 21, and 42 days post–focal radiation treatment (FRT) in C57BL/6 male mice confirmed the development of senescent cells and the senescence-associated secretory phenotype (SASP). Accumulation of senescent cells and SASP markers were correlated with a significant reduction in bone architecture at 42 days post-FRT. To test if senolytic drugs, which clear senescent cells, alleviate FRT-related bone damage, we administered the senolytic agents, dasatinib (D), quercetin (Q), fisetin (F), and a cocktail of D and Q (D+Q). We found moderate alleviation of radiation-induced bone damage with D and Q as stand-alone compounds, but no such improvement was seen with F. However, the senolytic cocktail of D+Q reduced senescent cell burden as assessed by TIF+ osteoblasts and osteocytes, markers of senescence (p16 Ink4a and p21), and key SASP factors, resulting in significant recovery in the bone architecture of radiated femurs. In summary, this study provides proof of concept that senescent cells play a role in radiotherapy-associated bone damage, and that reduction in senescent cell burden by senolytic agents is a potential therapeutic option for alleviating radiotherapy-related bone deterioration. © 2020 American Society for Bone and Mineral Research.

AbstractBackgroundAdvanced glycation end products (AGEs) are formed via the nonenzymatic glycation of sugars with amino acids. Two AGEs, Nε-(1-carboxymethyl)-L-Lysine (CML) and pentosidine, have been observed to be elevated in subjects suffering from a multitude of chronic disease states, and accumulation of these compounds may be related to the pathophysiology of disease progression and aging.MethodsWe describe here the development and validation of a specific and reproducible LC-MS/MS method to quantify CML and pentosidine in human serum with lower limits of quantitation of 75 ng/mL and 5 ng/mL, respectively. The analyte calibration curve exhibited excellent linearity at a range of 0–10 900 ng/mL for CML and 0–800 ng/mL for pentosidine. High-low linearity of 5 serum pairs was assessed, with a mean recovery of 103% (range 94—116%) for CML, and 104% (range 97—116%) for pentosidine.ResultsSerum concentrations of CML and pentosidine were quantified in 30 control and 30 subjects with chronic renal insufficiency. A significant increase in both analytes was observed in renal failure compared to control subjects (2.1-fold and 8.4-fold, respectively; P < 0.001 for both). In a separate cohort of 49 control versus 95 subjects with type 2 diabetes mellitus (T2DM), serum CML but not serum pentosidine, was significantly elevated in the T2DM patients, and CML was also correlated with glycemic control, as assessed by hemoglobin A1c (r = 0.34, P < 0.001).ConclusionsThese mass spectroscopy-based assays for serum CML and pentosidine should be useful in accurately evaluating circulating levels of these key AGEs in various disease states.

AbstractBackground: Osteocalcin (Oc), a serum marker of bone turnover, circulates in several forms. We developed an assay for intact human Oc and investigated its clinical features.Methods: We generated goat antibodies and N- and C-terminal Oc. The former was used on solid phase (polystyrene beads), and the latter was used as the tracer in an IRMA.Results: The assay was linear with no cross-reactivity to Oc(1–43), total imprecision (CV) of <10%, and recovery of 100% ± 10%. Assay values for intact Oc in EDTA plasma samples were unchanged at 18–25 °C for 6 h. Values for intact Oc in serum, EDTA plasma, and heparin plasma samples did not change after storage on ice for 8 h. Serum samples from patients with various conditions were stored at −70 or −135 °C for up to 5 years and yielded z-scores comparable to an Oc(1-43) IRMA for all conditions except for renal failure. In renal failure, the Oc(1–43) assay values were increased, whereas the intact assay values were in the reference interval.Conclusion: Decreases in Oc assay values are inhibited by calcium chelation, and slowed by reduced temperatures. The described assay for intact Oc allows improved specificity for bone compared with an assay for Oc(1–43).

Abstract During the workshop, experts discussed the state of the science. The U.S. Food and Drug Administration (FDA) has approved several medications to prevent osteoporotic fractures. These include bisphosphonates (BPs), denosumab, teriparatide, estrogens, and selective estrogen-receptor modulators. BPs are a first line of pharmacologic treatment for most women and men who have osteoporosis. Despite the efficacy of short-term use of BPs and other osteoporosis medications, treatment rates are low and appear to be decreasing. This talk would describe the problem/epidemiology of fracture prevention in the United States; the importance of drug therapy and their effectiveness; the limited evidence regarding long-term use of drug therapies; the questions surrounding the application of drug holidays; and the complex physician and patient factors that impact the use of and adherence to osteoporotic drugs.