United States

Background: In adolescents with severe obesity, long-term weight loss maintenance using lifestyle therapy alone is hampered by numerous biological adaptations favoring weight regain such as increased appetite and sense of food palatability and decreased satiety and resting energy expenditure. Anti-obesity pharmacotherapy may have a role in mitigating some of these physiological adaptations, thereby enhancing weight loss maintenance. We conducted a randomized, double-blind, placebo-controlled clinical trial to evaluate the effect of the glucagon-like peptide-1 receptor agonist (GLP-1RA) exenatide extended release (XR) on the maintenance of BMI reduction and improvements in cardiometabolic risk factors induced by short-term meal replacement therapy (MRT) among adolescents with severe obesity. Methods: One-hundred adolescents ages 12 to &lt;18 years with BMI ≥120% of the 95th percentile engaged in an MRT intervention consisting of pre-portioned meals averaging 1,400 kcals/day with a goal of reducing BMI by ≥5% within eight weeks. Participants achieving this goal were randomized 1:1 to either exenatide XR (2 mg/week subcutaneously) + lifestyle therapy or matching placebo + lifestyle therapy for a subsequent 52 weeks. The primary outcome was mean percent change in BMI from randomization (post-MRT) to 52 weeks. Secondary outcomes included changes in body fat (DXA) and cardiometabolic risk factors. Results: Sixty-six participants (mean age 16±1.5 years; 47% female; mean BMI 36.9±4.4 kg/m2) achieved ≥5% BMI reduction with MRT and were randomized; 56 (85%) completed the 52-week visit. From randomization (post-MRT) to 52-weeks, the exenatide and placebo group mean BMI increased 4.6% and 10.1%, respectively. The prespecified intention-to-treat, last observation carried forward primary analysis demonstrated a placebo-subtracted exenatide treatment effect of -4.1% (95% CI -8.6 to 0.5, p=0.078). The per-protocol analysis (excluding participants with major protocol deviations) demonstrated a placebo-subtracted exenatide treatment effect of -5.7% (95% CI -10.9 to -0.6, p=0.030). The placebo-subtracted exenatide treatment effect on total body fat was -3.0 kg (95% CI -6.7 to 0.7, p=0.108), systolic blood pressure -3.2 mmHg (95% CI -7.0 to 0.7, p=0.107), and triglycerides to HDL ratio -0.6 (95% CI -1.2 to 0.0, p=0.050). Exenatide was generally well-tolerated and the adverse event profile was similar to previous reports of GLP-1RAs. Conclusion: The steep trajectory of weight regain following short-term MRT, particularly in the placebo group, underscores the challenge many adolescents encounter in maintaining weight loss over time. GLP-1RA treatment with once-weekly exenatide appears to partly mitigate the propensity toward weight regain after initial dietary-induced weight loss among adolescents with severe obesity.?? 

ENDO 2021

Once-Weekly Exenatide Enhances Weight Loss Maintenance in Adolescents with Severe Obesity: A Randomized, Placebo-Controlled Trial

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ENDO 2020

ENDO is the place where leading experts, researchers, and the most respected clinicians in the field come together to share the latest findings in hormone science and discuss breakthroughs in clinical care.

Background: In adolescents with severe obesity, long-term weight loss maintenance using lifestyle therapy alone is hampered by numerous biological adaptations favoring weight regain such as increased appetite and sense of food palatability and decreased satiety and resting energy expenditure. Anti-obesity pharmacotherapy may have a role in mitigating some of these physiological adaptations, thereby enhancing weight loss maintenance. We conducted a randomized, double-blind, placebo-controlled clinical trial to evaluate the effect of the glucagon-like peptide-1 receptor agonist (GLP-1RA) exenatide extended release (XR) on the maintenance of BMI reduction and improvements in cardiometabolic risk factors induced by short-term meal replacement therapy (MRT) among adolescents with severe obesity. Methods: One-hundred adolescents ages 12 to <18 years with BMI ≥120% of the 95th percentile engaged in an MRT intervention consisting of pre-portioned meals averaging 1,400 kcals/day with a goal of reducing BMI by ≥5% within eight weeks. Participants achieving this goal were randomized 1:1 to either exenatide XR (2 mg/week subcutaneously) + lifestyle therapy or matching placebo + lifestyle therapy for a subsequent 52 weeks. The primary outcome was mean percent change in BMI from randomization (post-MRT) to 52 weeks. Secondary outcomes included changes in body fat (DXA) and cardiometabolic risk factors. Results: Sixty-six participants (mean age 16±1.5 years; 47% female; mean BMI 36.9±4.4 kg/m2) achieved ≥5% BMI reduction with MRT and were randomized; 56 (85%) completed the 52-week visit. From randomization (post-MRT) to 52-weeks, the exenatide and placebo group mean BMI increased 4.6% and 10.1%, respectively. The prespecified intention-to-treat, last observation carried forward primary analysis demonstrated a placebo-subtracted exenatide treatment effect of -4.1% (95% CI -8.6 to 0.5, p=0.078). The per-protocol analysis (excluding participants with major protocol deviations) demonstrated a placebo-subtracted exenatide treatment effect of -5.7% (95% CI -10.9 to -0.6, p=0.030). The placebo-subtracted exenatide treatment effect on total body fat was -3.0 kg (95% CI -6.7 to 0.7, p=0.108), systolic blood pressure -3.2 mmHg (95% CI -7.0 to 0.7, p=0.107), and triglycerides to HDL ratio -0.6 (95% CI -1.2 to 0.0, p=0.050). Exenatide was generally well-tolerated and the adverse event profile was similar to previous reports of GLP-1RAs. Conclusion: The steep trajectory of weight regain following short-term MRT, particularly in the placebo group, underscores the challenge many adolescents encounter in maintaining weight loss over time. GLP-1RA treatment with once-weekly exenatide appears to partly mitigate the propensity toward weight regain after initial dietary-induced weight loss among adolescents with severe obesity.?? 

technical paper

ENDO is the leading meeting for endocrinology research and clinical care worldwide. 

CRN04894 is an orally administered nonpeptide that is a potent and selective antagonist for adrenocorticotropic hormone (ACTH) acting at the melanocortin 2 receptor (MC2R) and is currently under development for the treatment of diseases of ACTH excess such as Cushing’s disease, congenital adrenal hyperplasia, and ectopic ACTH-secreting tumors. Cushing’s disease results from an adenoma derived from pituitary corticotropic cells that secrete excess ACTH, whereas ectopic ACTH syndrome arises from nonpituitary ACTH secreting tumors. Congenital adrenal hyperplasia is a genetic disease that results in cortisol deficiency leading to high levels of ACTH and adrenal androgens. Each of these indications is characterized by high ACTH levels that act on MC2R expressed in the adrenal cortex to drive pathological elevations of adrenally derived steroid hormones. CRN04894 blocks the action of ACTH at MC2R, providing a potential novel treatment for these diseases. Preclinical models of chronic hypercortisolemia include implantation of ACTH-secreting pituitary tumor cells in mice and continuous administration of ACTH via subcutaneously implanted osmotic pumps in rats. These models induce features consistent with human diseases of ACTH excess including hypercortisolemia and hypertrophy of the adrenal glands. We employed both rodent models to examine the pharmacodynamic effects of CRN04894 on corticosterone levels and adrenal gland morphology. In the mouse pituitary tumor model, subcutaneous inoculation of the ACTH-secreting mouse pituitary tumor cell line, AtT-20, into immunodeficient mice resulted in formation of tumors and increased plasma ACTH and corticosterone levels. Repeated daily oral administration of CRN04894 for 14 days dose-dependently and robustly suppressed plasma corticosterone levels in mice with AtT-20 tumors. In the rat model, subcutaneous implantation of osmotic pumps delivering ACTH resulted in increased corticosterone levels, reduction in body weight, and hypertrophy of the adrenal glands after 7 days. Daily oral administration of CRN04894 over 7 days dose-dependently suppressed corticosterone levels, mitigated the effect of ACTH excess on body weight, and rescued the adrenal gland hypertrophy. These findings provide evidence that CRN04894 functions as an effective ACTH antagonist at MC2R to suppress adrenal corticosterone secretion in both mouse and rat models of ACTH excess and hypercortisolemia, thus providing a strong rationale for its potential therapeutic utility in diseases of ACTH excess. This work was supported in part by an SBIR grant from the NIH awarded to Dr. Struthers (R43- DK115245)?? 

Effects of CRN04894, a Nonpeptide Orally Bioavailable ACTH Antagonist, on Corticosterone in Rodent Models of ACTH Excess

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy affecting individuals across a broad age spectrum. Disease rarity, scarcity of pre-clinical models, lack of effective targeted therapy and limited clinical trials have contributed to poor prognosis for patients with ACC. Identifying targetable genetic drivers and pathways to guide precision medicine approaches is therefore critical to improve outcomes. The purpose of this study was to analyze the genomic profile of a large cohort of ACC to identify potential therapeutic targets. FoundationOne (Foundation Medicine Inc.; FMI, Cambridge, MA) is a next-generation sequencing-based platform for somatic genetic testing in solid tumors. The FoundationOne genomic data and limited demographic data through 2018 for 364 unique ACC specimens were analyzed. The cohort of 364 tumors were from 222 females and 141 males (1 gender unknown). The mean age (SD) was 48.6 (13.6) for females and 50.6 (12.20) for males with overall median age of 52 years. A total of 3117 genomic alterations were identified impacting 457 genes. The median number of genomic alterations per tumor was 7 (range 1-56), with single nucleotide variants and indels being the most common alterations (median=4), followed by copy number alterations (median=1) and rearrangements (median=0). The most frequently altered genes were TP53 (38%), CTNNB1 (28%), ZNRF3 (17%), CDKN2A (13%), ATRX (11%), TERT promoter (10%). Several novel recurrent alterations were identified including IL7R (6%), LRP1B (8%), FRS2 (4%), PTCH1 (4%) and KRAS (3%). Pathway enrichment analysis confirmed that tumor suppressor genes (51%) and Wnt signaling pathways (51%) are the most commonly dysregulated in ACC tumors. Epigenetic alterations, including histone modification (38%), SWI/SNF (21%) and DNA methylation (8%), affected upwards of one third of ACC tumors. Mutation signature analysis identified tumors with signatures 6, 15 and 26 associated with defective DNA mismatch repair (MMR), which was not reported previously. In addition, fifty ACCs (13.7%) exhibited 60 genomic alterations in MMR genes, MLH1, MSH2, MSH6 and PMS2, which included 49 SNVs/indels, 10 CNAs and one truncating rearrangement. In addition to MMR gene alterations, potentially actionable (www.oncokb.org) genomic alterations were found in 46 genes in 213 (58.5%) ACCs. In summary, this study represents the largest to date genomic analysis of ACC that showed that over 50% of ACC tumors had potentially actionable genomic alterations. Approximately 13% of tumors had an alteration in MMR pathway, suggesting that immunotherapy is a relevant therapeutic modality in a significant subset of patients with ACC.?? 

Insights From Targeted Genetic Analysis of 364 Adrenocortical Carcinomas

Germline SUCLG2 Variants in Patients With Pheochromocytoma and Paraganglioma

Autoimmune Addison’s disease is the predominant cause of primary adrenal failure, and is highly heritable. The genetic background has remained poorly understood due to the low prevalence and complex inheritance of the disease. We performed a genome-wide association study, which identified nine independent risk loci (P < 5 × 10-8). In addition to novel and previous risk loci involved in lymphocyte functionality, we further associated autoimmune Addison’s disease with two independent protein-coding alterations in the gene Autoimmune Regulator (AIRE). The most striking is the amino-acid substitution p.R471C (rs74203920, OR = 3.4 (2.7-4.3), P = 9.0 × 10-25), which introduces an additional cysteine residue in the zinc-finger motif of the PHD2 domain of AIRE. This unbiased elucidation of the genetic contribution to development of autoimmune Addison’s disease points to the importance of central immunological tolerance, and explains 35-41 percent of heritability.?? 

Genome-Wide Association Study Links Autoimmune Addison’s Disease to Break of Central Tolerance

Background The ESE-ENSAT guidelines on the management of adrenocortical carcinoma (ACC) suggest adjuvant mitotane for patients at high risk of recurrence following radical surgery. This indication has a limited evidence base, lacking results from randomized controlled trials. No suggestion for or against adjuvant mitotane in low-risk patients was given, since studies did not stratify patients for prognosis. The randomized controlled study ADIUVO compared the efficacy of adjuvant mitotane treatment vs. observation in prolonging recurrence-free survival (RFS) in ACC patients at low-intermediate risk of recurrence.?Methods The main inclusion criteria were: stage I-III ACC, R0 surgery, and Ki-67 ≤10%. Patients were randomly assigned 1:1 to adjuvant mitotane (MIT) or observation (OBS). The primary endpoint of the study was RFS. Patients who refused randomization were offered inclusion in the ADIUVO OBSERVATIONAL study. In this prospective, observational study, patients were managed as in the ADIUVO study. A total of 91 patients were enrolled in ADIUVO, 45 in the MIT and 46 in the OBS arm. Baseline characteristics of patients were perfectly matched between the 2 arms: median age, 51 vs. 50.5 years; female, 73% vs. 67%; stage I, 20% vs. 26%; stage II, 67% vs. 63%, stage III, 13% vs. 11%; ACC secretion 44% vs. 36%; Weiss 5 vs. 5; respectively. In ADIUVO OBSERVATIONAL, 42 patients were treated with mitotane and 53 were untreated. Baseline characteristics of patients were matched between the 2 groups and with MIT and OBS groups in ADIUVO. Thus, the ADIUVO OBSERVATIONAL cohorts could be analyzed in parallel to those of ADIUVO.?Results In the ADIUVO study, recurrences were 8 in the MIT and 11 in the OBS arm, while deaths were 2 and 5, respectively. RFS and overall survival (OS) did not significantly differ between the 2 arms. Tumor size was a predictor of RFS in multivariable analysis. In the OBS arm, the HR for recurrence was 1.321 (95%CI, 0.55-3.32, p=0.54) and HR for death 2.171 (95%CI, 0.52-12.12, p=0.29). The survival analysis in the ADIUVO OBSERVATIONAL study confirmed the findings of ADIUVO. Given the outcome of both studies, the NNT is 55.?Conclusions ACC patients at low-intermediate risk of recurrence after surgery are a minority; however, they show a far better prognosis than expected (5-year RFS is about 75%) and do not benefit significantly from adjuvant mitotane. The results of the ADIUVO study do not support routine use of adjuvant mitotane in this subset of patients, who may thus avoid a potentially toxic treatment. This is an important step toward personalization of ACC care.?? 

Results of the ADIUVO Study, the First Randomized Trial on Adjuvant Mitotane in Adrenocortical Carcinoma Patients

Background: Adrenocortical carcinoma (ACC) has an aggressive but heterogeneous behaviour. ENSAT stage and Ki67 proliferation index are used to predict clinical outcome but are limited in distinguishing patients with different risk of disease progress. We aimed to validate the prognostic role of a previously proposed points-based score (mGRAS) in a large ACC cohort.?Methods: We included ACC patients who underwent adrenalectomy between 2010 and 2019, had complete clinical and histopathological data, and did not participate in our previous studies (Libe et al. Ann Oncol 2015; Lippert et al. JCEM 2018). The mGRAS score was calculated as follows: age (<50yr=0; ≥50yr =1), symptoms (no=0; yes=1), ENSAT stage (1-2=0; 3=1; 4=2), resection status (R0=0; RX=1; R1=2; R2=3), and Ki67 (0-9%=0; 10-19%=1; ≥20%=2 points), generating scores from 0 to 9 and four mGRAS groups (scores 0-1, 2-3, 4-5, and 6-9). Progression-free survival (PFS) and disease-specific survival (DSS) were the primary and secondary endpoints, respectively. The discriminative performance of mGRAS was investigated using the Harrell’s C-index and Royston-Sauerbrei’s R2D statistic.?Results: A total of 942 ACC patients from 14 ENSAT centres were included (38% men; median age 50yrs (interquartile range 38, 61)). The four mGRAS groups showed superior prognostic discrimination compared to the individual clinical and histological parameters for both PFS and DSS (C-index 0.71, R2D=0.30 and 0.77, R2D=0.46, respectively); ENSAT staging was the second best discriminator (C-index 0.67, R2D 0.21 and 0.72, R2D=0.35, respectively). An even better prognostic discrimination was observed using the ten mGRAS scores individually (C-index 0.73, R2D=0.30, and 0.79, R2D=0.45 for PFS and DSS, respectively). The superiority of mGRAS was confirmed when separately considering patients treated or untreated with adjuvant mitotane (n=481 vs 314). In mitotane-treated patients, the four mGRAS groups showed better performance in predicting PFS than Ki67 index (C-index 0.66, R2D 0.18 vs C-index 0.62, R2D 0.12).?Conclusion: The prognostic performance of mGRAS is superior to that of ENSAT staging and Ki67. This simple score may guide personalised treatment decisions in patients with ACC, e.g. regarding the need for adjuvant therapy and frequency of monitoring.?? 

Modified GRAS Score for Prognostic Classification of Adrenocortical Carcinoma: An ENSAT Multicentre Study

Background: High-specific-activity iodine-131 meta-iodobenzylguanidine (HSA I-131 MIBG; AZEDRA®) has been approved for the treatment of adult and pediatric patients (pts) 12 years and older with iobenguane scan positive, unresectable, locally advanced or metastatic PPGL who require systemic anticancer therapy. We have previously presented data showing improved biomarker responses in pts treated with HSA I-131 MIBG. Here we report the impact of biomarker status on the study primary endpoint and objective tumor response. Methods: Pts with iobenguane-avid PPGL who were ineligible for surgery, failed prior therapy or not candidates for chemotherapy, and on a stable antihypertensive medication regimen were treated. Pts received up to two therapeutic doses, each at ~18.5 GBq (or 296 MBq/kg for pts ≤62.5 kg), administered ~90 days apart. Biomarkers were analyzed at baseline and over a 12-month efficacy period. Confirmed biochemical responses (at least ≥ 50% decrease in abnormal tumor marker value for all hypersecreted biomarkers) required subsequent responses to be identical to or better compared with the previous assessment. The primary endpoint was clinical benefit, defined as the proportion of pts with at least 50% reduction of all antihypertensive medication(s) for ≥6 months beginning during the efficacy period. The secondary endpoint, confirmed objective tumor response by RECIST, was also evaluated. Results: 68 pts received at least one therapeutic dose of HSA I-131 MIBG. For all pts with hypersecretory tumors (with a baseline biochemical marker level of ≥1.5× ULN) (n=60), a comparison of biomarker response with antihypertensive therapy yielded a correlation coefficient of 0.35 (P = 0.006; Fisher exact P = 0.012). For pts with norepinephrine only-hypersecreting tumors (n=31), a correlation coefficient of 0.47 (P = 0.008; Fisher exact P = 0.015) was observed. The overall biomarker response also correlated with objective tumor response (n=55) yielding a correlation coefficient of 0.36 (P = 0.007; Fisher exact P = 0.012) for all pts with hypersecreted biomarkers. Pts who were not biochemical hypersecretors for any biomarker (n=6) had only one responder for the primary endpoint and no objective tumor responses. Conclusions: The biomarker data from this study establish a moderate but statistically significant correlation between biomarker response following treatment with HSA I-131 MIBG and objective tumor response and durable reduction of antihypertensive therapy. This correlation was improved with norepinephrine only-hypersecreting tumors in pts with unresectable, locally advanced or metastatic PPGL.?? 

Biochemical Tumor Marker Status and Its Role in Treatment Response in Patients Who Received High-Specific-Activity I-131 MIBG in Advanced Pheochromocytoma and Paraganglioma (PPGL): Results From a Pivotal Phase 2 Clinical Trial

Background: Endogenous Cushing’s syndrome (CS) refers to an inappropriate hypercortisolism usually caused by either Cushing’s disease (CD) or adrenal CS (ACS). CS results in significant morbidity and excess mortality if untreated. Even in treated cases there is often a significant health burden. Due to the rarity of CS (incidence ~ 1/1M population) , single cohort studies have insufficient power for reporting accurate mortality data. Only one previous systematic review and meta-analysis for CS has been reported that limited its scope to the inclusion of specific CD subgroup. Aims: To perform a meta-analysis and meta-regression analysis of all-cause and specific cause -mortality amongst patients with benign endogenous CS.Methods: The protocol was registered in PROSPERO (CRD42017067530). Searches were undertaken of PubMed, EMBASE, CINHAL, web of science and Cochrane Central from start until April 2019. The primary outcomes were proportion of mortality and SMR. The meta-analysis was done with STATA version 16.1 software. The I2 test, subgroup analysis and meta-regression statistics were used to assess heterogeneity among included studies. Results: A total of 11,527 articles, were retrieved. 87 articles with 100 study cohorts containing 17,276 CS patients reporting mortality were included. Fifty-three study cohorts reported Cushing’s disease (CD) patients, 27 study cohorts reported for adrenal CS patients and 20 studies cohorts reported on both types of CS. The overall SMR of all type CS was 2.91 (95% CI 2.41-3.68) with I2 =40.3%. The SMR for CD was 3.27 (95% CI 2.33-4.21) with I2 = 55.6%. The SMR in ACS was 1.62 (95% CI 0.08-3.16) with I2 =0.0%. The overall proportion of death in CS was 0.05 (95% CI 0.03-0.06) with I2 =51.86%; in CD was 0.04 (95% CI 0.03-0.06) with I2 = 62.7% and in ACS 0.06 (95% CI 0.04-0.11) with I2 = 40.3 %. The proportion of death during the 30-day operative period was highest before 1991 at 0.07 and decreased to 0.03 in 1991-2000 to 0.01 in 2001-2010 and zero after 2011. The causes of death reported across 64 studies were cardiac causes (24.7%), infection (14.4%), cerebrovascular diseases (9.4%), malignancy (9.0%), thromboembolism (4.2%), active disease (2.9%), and adrenal insufficiency (2.7%).Conclusion: CS is associated with increase in overall mortality. Advances in operative techniques and care have decreased peri-operative mortality over a 20 year period. The causes of death highlight the need for aggressive management of cardiovascular risk, prevention of thrombo-embolism, infection control and a normalised cortisol level.?? 

Mortality and Specific Causes of Death in Endogenous Cushing’s Syndrome: A Systematic Review, Meta-Analysis and Meta-Regression

Age-induced osteoporosis is characterized by a progressive decline in bone formation and increase in bone resorption with uncoupled activities of osteoblasts and osteoclasts. Parathyroid hormone (PTH) is used in the clinic to treat osteoporosis due to its anabolic actions on bone via binding to the PTH receptor (PPR). The receptor is highly expressed in cells of the osteoblastic lineage, including osteocytes. Osteocytes are the most abundant cells in bone and serve as a key regulator of bone remodeling. Despite the significant role of PPR signaling in skeletal homeostasis, its function in osteocytes during aging remains unclear. We have gathered preliminary data demonstrating that mice lacking PPR predominantly in osteocytes (Dmp1-PPRKO) have marked age-induced bone loss due to increased bone resorption and suppressed bone formation. These mice, with aging, develop characteristics of skeletal senescence: a decrease in osteoprogenitors and an increase in bone marrow adiposity and p16Ink4a/Cdkn2a expression in bone. Since senescence of cells in the bone microenvironment has been reported as a cause of age-induced bone loss, we hypothesized that PPR signaling protects osteocytes from senescence. To test this hypothesis, we generated osteocytes (Ocy454-12H), in which the PPR expression was ablated using CRISPR/Cas9 technique. Ocy454-12H-PPRKO and Ocy454-12H-PPRCtrl cells were treated with PTH followed by an exposure to hydrogen peroxide (H2O2). High levels of intracellular reactive oxygen species (ROS), including H2O2, promote protein and DNA oxidation, resulting in cell death and senescence. PTH treatment significantly suppressed the increase in H2O2-induced cell death, measured by resazurin-based assays, in PPRCtrl but not in PPRKO cells. We analyzed intracellular ROS levels using a fluorescent probe and found that PTH treatment significantly suppressed the increase in ROS upon H2O2 exposure, suggesting an antioxidant function of PTH in osteocytes. To further investigate if PTH prevents osteocytes from oxidative stress-induced senescence, we examined senescence-associated β-galactosidase (SA β-gal) activity in cells that were treated with PTH followed by an exposure to low doses of H2O2. Compared to untreated and PPRKO groups, treatment with PTH significantly decreased the number of SA β-gal positive cells, demonstrating that PPR signaling protects osteocytes, and possibly other osteoblastic cells, from H2O2-induced cellular senescence. PTH treatment reduced mRNA expression of p21/Cdkn1a. Taken together these results demonstrate that PPR signaling is important to protect osteocytes from cellular senescence.?? 

PTH Protects Osteocytes From Oxidative Stress and Cellular Senescence

Opioid use is associated with a three to four-fold increase in fracture risk, which is higher in males compared to females. Although one component of that risk may be falls, there is also evidence of altered bone remodeling. However, the mechanisms of these effects are not entirely clear. Our aim was to develop a mouse model of opioid-induced bone loss and study the impact on bone turnover and potential miRNA-mediated regulatory mechanisms. We evaluated the effects of sustained morphine treatment on the skeleton and metabolism of male and female C57BL/6J mice by treating with vehicle (0.9% saline) (n=9-11) or morphine (18 mg/kg) (n=11) using subcutaneous osmotic minipumps for 25 days. Morphine did not influence body weight or food intake, but did reduce fat mass in both sexes. All mice treated with morphine had higher resting energy expenditure and respiratory quotient, indicating a shift toward carbohydrate metabolism. After 25 days of treatment, microComputed Tomography (µCT) analyses indicated that morphine-treated male mice lost 15% of trabecular bone volume fraction (Tb.BV/TV) and 14% of Tb. bone mineral density (BMD) (p<0.05) in the distal femur compared to vehicle, but there were no changes in cortical bone. Females did not lose bone, suggesting differences may be hormone-related. Despite these sex differences, males and females had similar levels of morphine exposure, measured by LC-MS/MS. Histomorphometric analyses demonstrated that in males, morphine reduced bone formation rate (p<0.05) compared to vehicle, but did not impact osteoclast parameters. Consistent with this, morphine reduced bone formation marker gene expression in the tibia of males (including Bglap and Dmp1). Circulating miRNA profiles were interrogated in serum collected at day 12 from vehicle- and morphine-treated male and female mice. While very few changes were present in females, there were 14 differentially expressed miRNAs in males treated with morphine that reached a threshold of ≥ 2-fold change and p<0.01. After target pathway analysis (DIANA miR Path V.3 using experimentally validated miRNA/mRNA targets (Tarbase V.7)), we found that the four upregulated miRNAs (miR-484, -223-3p, -328-3p, and -3107-3p) were associated with 13 enriched KEGG pathways (p<0.05), including fatty acid metabolism pathways (p<0.001). Fatty acid metabolism has recently been linked to osteoblast function, and suppression of such pathways is consistent with the finding of increased respiratory quotient. In summary, morphine leads to trabecular bone loss due to reduced bone formation in males. miRNA findings indicate this may be due to altered metabolic control of mineralization. Further investigation into hormonal and metabolic dependency of morphine-induced bone formation changes could lead to clinical mitigation strategies for preventing the adverse effects of opioids on bone health.?? 

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Once-Weekly Exenatide Enhances Weight Loss Maintenance in Adolescents with Severe Obesity: A Randomized, Placebo-Controlled Trial

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Effects of CRN04894, a Nonpeptide Orally Bioavailable ACTH Antagonist, on Corticosterone in Rodent Models of ACTH Excess

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