Duplications disrupt chromatin architecture and rewire GPR101-enhancer communication in X-linked acrogigantism.

X-linked acrogigantism (X-LAG) is the most severe form of pituitary gigantism and is characterized by aggressive growth hormone (GH)-secreting pituitary tumors that occur in early childhood. X-LAG is associated with chromosome Xq26.3 duplications (the X-LAG locus typically includes VGLL1, CD40LG, ARHGEF6, RBMX, and GPR101) that lead to massive pituitary tumoral expression of GPR101, a novel regulator of GH secretion. The mechanism by which the duplications lead to marked pituitary misexpression of GPR101 alone was previously unclear. Using Hi-C and 4C-seq, we characterized the normal chromatin structure at the X-LAG locus. We showed that GPR101 is located within a topologically associating domain (TAD) delineated by a tissue-invariant border that separates it from centromeric genes and regulatory sequences. Next, using 4C-seq with GPR101, RBMX, and VGLL1 viewpoints, we showed that the duplications in multiple X-LAG-affected individuals led to ectopic interactions that crossed the invariant TAD border, indicating the existence of a similar and consistent mechanism of neo-TAD formation in X-LAG. We then identified several pituitary active cis-regulatory elements (CREs) within the neo-TAD and demonstrated in vitro that one of them significantly enhanced reporter gene expression. At the same time, we showed that the GPR101 promoter permits the incorporation of new regulatory information. Our results indicate that X-LAG is a TADopathy of the endocrine system in which Xq26.3 duplications disrupt the local chromatin architecture forming a neo-TAD. Rewiring GPR101-enhancer interaction within the new regulatory unit is likely to cause the high levels of aberrant expression of GPR101 in pituitary tumors caused by X-LAG.

Filamin A is involved in human intrahepatic cholangiocarcinoma aggressiveness and progression.

BACKGROUND & AIMS: Intrahepatic cholangiocarcinoma (iCCA) is a primary liver tumour, characterized by poor prognosis and lack of effective therapy. The cytoskeleton protein Filamin A (FLNA) is involved in cancer progression and metastasis, including primary liver cancer. FLNA is cleaved by calpain, producing a 90 kDa fragment (FLNACT ) that can translocate to the nucleus and inhibit gene transcription. We herein aim to define the role of FLNA and its cleavage in iCCA carcinogenesis. METHODS & RESULTS: We evaluated the expression and localization of FLNA and FLNACT in liver samples from iCCA patients (n = 82) revealing that FLNA expression was independently correlated with disease-free survival. Primary tumour cells isolated from resected iCCA patients expressed both FLNA and FLNACT , and bulk RNA sequencing revealed a significant enrichment of cell proliferation and cell motility pathways in iCCAs with high FLNA expression. Further, we defined the impact of FLNA and FLNACT on the proliferation and migration of primary iCCA cells (n = 3) and HuCCT1 cell line using silencing and Calpeptin, a calpain inhibitor. We observed that FLNA silencing decreased cell proliferation and migration and Calpeptin was able to reduce FLNACT expression in both the HuCCT1 and iCCA cells (p < .05 vs. control). Moreover, Calpeptin 100 µM decreased HuCCT1 and primary iCCA cell proliferation (p <.00001 vs. control) and migration (p < .05 vs. control). CONCLUSIONS: These findings demonstrate that FLNA is involved in human iCCA progression and calpeptin strongly decreased FLNACT expression, reducing cell proliferation and migration.

Prediction of adrenal insufficiency after pituitary surgery: a retrospective study using beckman access cortisol assay.

PURPOSE: Identifying patients requiring glucocorticoid replacement therapy after pituitary surgery is challenging as the tests commonly used for the diagnosis of secondary adrenal insufficiency (SAI) are not recommended in the immediate postoperative period. There are controversial data on the role of postoperative days' morning cortisol, with no specific data for each cortisol assay. The aim of this study is to investigate the reliability of 8.00 a.m. cortisol of the first and second postoperative days in predicting SAI. METHODS: Data of patients underwent pituitary surgery in Humanitas Research Hospital in Italy, from March 2017 to August 2022, were retrospectively analyzed. Definitive diagnosis of SAI was made through ACTH test 1 µg six weeks after surgery. Cortisol was measured through Beckman Access Cortisol and the diagnosis of SAI was made if cortisol peak was below 14.8 µg/dL (408 nmol/L) at 30 or 60 min after stimulus. RESULTS: Of the sixty-four patients enrolled, seven developed SAI. The ROC curves demonstrated that both first- and second-day postoperative 8.00 a.m. cortisol predict SAI (AUC 0.94 and 0.95, respectively). The optimal thresholds were 15.6 µg/dL (430.3 nmol/L; accuracy 89%) for the first day and 11.5 µg/dL (317.2 nmol/L, accuracy 81%) for the second day. Patients who developed SAI had larger tumors (p = 0.004) and lower fT4 (p = 0.038) before surgery. CONCLUSIONS: Clinicians might rely on the first- and second- postoperative days 8.00 a.m. cortisol to identify patients to discharge with glucocorticoid replacement therapy waiting for the confirmation of SAI through the ACTH test.

The Novel SSTR3 Agonist ITF2984 Exerts Antimitotic and Proapoptotic Effects in Human Non-Functioning Pituitary Neuroendocrine Tumor (NF-PitNET) Cells.

Somatostatin receptor ligands (SRLs) with high affinity for somatostatin receptors 2 and 5 (SSTR2 and SSTR5) are poorly efficacious in NF-PitNETs, expressing high levels of SSTR3. ITF2984 is a pan-SSTR ligand with high affinity for SSTR3, able to induce SSTR3 activation and to exert antitumoral activity in the MENX rat model. The aim of this study was to test ITF2984's antiproliferative and proapoptotic effects in NF-PitNET primary cultured cells derived from surgically removed human tumors and to characterize their SSTR expression profile. We treated cells derived from 23 NF-PitNETs with ITF2984, and a subset of them with octreotide, pasireotide (SRLs with high affinity for SSTR2 or 5, respectively), or cabergoline (DRD2 agonist) and we measured cell proliferation and apoptosis. SSTR3, SSTR2, and SSTR5 expression in tumor tissues was analyzed by qRT-PCR and Western blot. We demonstrated that ITF2984 reduced cell proliferation (-40.8 (17.08)%, p < 0.001 vs. basal, n = 19 NF-PitNETs) and increased cell apoptosis (+41.4 (22.1)%, p < 0.001 vs. basal, n = 17 NF-PitNETs) in all tumors tested, whereas the other drugs were only effective in some tumors. In our model, SSTR3 expression levels did not correlate with ITF2984 antiproliferative nor proapoptotic effects. In conclusion, our data support a possible use of ITF2984 in the pharmacological treatment of NF-PitNET.

Real-World Effectiveness of Denosumab and Bisphosphonates on Risk of Vertebral Fractures in Women with Breast Cancer Undergoing Treatment with Aromatase Inhibitors.

Bone-active drugs are recommended to protect the skeleton from detrimental actions of aromatase inhibitors (AIs). However, most of literature data are focused on bone mineral density (BMD), whereas data on fractures are scant. The aim of this prospective study was to investigate the real-life effectiveness of denosumab, oral bisphosphonates (BPs) and intravenous zoledronate on risk of vertebral fractures (VFs) induced by AIs. 567 consecutive women (median age 62 years, range 28-83) with early breast cancer undergoing treatment with AIs were evaluated for morphometric VFs and BMD at baseline and after 18-24 months of follow-up. After enrollment, 268 women (47.3%) started denosumab 60 mg subcutaneously every 6 months, 115 (20.3%) BPs (59 with oral BPs and, 56 with intravenous zoledronate 5 mg/12 months), whereas 184 women (32.5%) were not treated with bone-active drugs for several reasons. During follow-up, 54 women (9.5%) developed incident VFs in association with age of subjects (P < 0.001), baseline FRAX scores for major fractures (P < 0.001) and hip fractures (P = 0.003), pre-existing VFs (P < 0.001), change in BMD at lumbar spine (P = 0.015), femoral neck (P = 0.003) and total hip (P < 0.001). Risk of VFs was higher in subjects who were untreated as compared to those treated with bone-active drugs (32/184 vs. 22/383; P < 0.001). Specifically, fracture risk was significantly decreased by denosumab [odds ratio (OR) 0.22; P < 0.001] and zoledronate (OR 0.27; P = 0.035), but not by oral BPs (P = 0.317). These data suggest that in real-world clinical practice, denosumab and zoledronate can reduce AI-related risk of VFs after only 24 months of treatment.

Pituitary Tumors: Genetic and Molecular Factors Underlying Pathogenesis and Clinical Behavior.

Pituitary neuroendocrine tumors (PitNETs) are the most common intracranial neoplasms. Although generally benign, they can show a clinically aggressive course, with local invasion, recurrences, and resistance to medical treatment. No universally accepted biomarkers of aggressiveness are available yet, and predicting clinical behavior of PitNETs remains a challenge. In rare cases, the presence of germline mutations in specific genes predisposes to PitNET formation, as part of syndromic diseases or familial isolated pituitary adenomas, and associates to more aggressive, invasive, and drug-resistant tumors. The vast majority of cases is represented by sporadic PitNETs. Somatic mutations in the α subunit of the stimulatory G protein gene (gsp) and in the ubiquitin-specific protease 8 (USP8) gene have been recognized as pathogenetic factors in sporadic GH- and ACTH-secreting PitNETs, respectively, without an association with a worse clinical phenotype. Other molecular factors have been found to significantly affect PitNET drug responsiveness and invasive behavior. These molecules are cytoskeleton and/or scaffold proteins whose alterations prevent proper functioning of the somatostatin and dopamine receptors, targets of medical therapy, or promote the ability of tumor cells to invade surrounding tissues. The aim of the present review is to provide an overview of the genetic and molecular alterations that can contribute to determine PitNET clinical behavior. Understanding subcellular mechanisms underlying pituitary tumorigenesis and PitNET clinical phenotype will hopefully lead to identification of new potential therapeutic targets and new markers predicting the behavior and the response to therapeutic treatments of PitNETs.

Vertebral Fractures Associated with Spinal Sagittal Imbalance and Quality of Life in Acromegaly: A Radiographic Study with EOS 2D/3D Technology.

INTRODUCTION: Acromegaly is commonly complicated by arthropathy and skeletal fragility with high risk of vertebral fractures (VFs). OBJECTIVE: This study aimed to assess whether VFs may be associated with sagittal spine deformities, arthropathy, impaired quality of life (QoL), pain, and disability. METHODS: Thirty-eight patients with acromegaly (median age: 55 years, 20 males) and 38 matched control subjects were evaluated by a low-dose sagittal and coronal planes, X-ray imaging system (EOS®-2D/3D) for morphometric VFs, radiological signs of spine arthropathy, and spine deformities (Cobb thoracic index ≥40°, pelvic incidence minus lumbar lordosis ≥10°, pelvic tilt >20°, and sagittal vertical axis ≥4 cm) determining sagittal spine imbalance. Acromegalic patients were also evaluated by questionnaires for QoL (Acromegaly QoL Questionnaire [AcroQoL] and Short Form-36 [SF-36]) and pain and disability (Western Ontario and McMaster University [WOMAC]). RESULTS: Acromegalic patients showed higher prevalence of thoracic hyperkyphosis (i.e., Cobb thoracic index ≥40°; p = 0.04) and pelvic tilt >20° (p = 0.02) than control subjects. VFs were found in 34.2% of acromegalic patients (p = 0.003 vs. control subjects), in relationship with higher prevalence of hyperkyphosis (p = 0.03), pelvic tilt >20° (p = 0.04), sagittal vertical axis ≥4 cm (p = 0.03), and moderate/severe subchondral degeneration (p = 0.01). Moreover, patients with VFs had lower AcroQoL general health (p = 0.007) and SF-36 general health (p = 0.002) scores and higher WOMAC pain (p = 0.003) and global (p = 0.009) scores than patients who did not fracture. CONCLUSIONS: In acromegaly, VFs may be associated with spine deformities and sagittal imbalance, spine arthropathy, impaired QoL, and disability.

Specific roles of G(i) protein family members revealed by dissecting SST5 coupling in human pituitary cells.

Despite intensive investigation over the past 20 years, the specific role played by individual G(i) protein family members in mediating complex cellular effects is still largely unclear. Therefore, we investigated the role of specific G(i) proteins in mediating somatostatin (SS) effects in somatotroph cells. Because our previous data showed that SS receptor type 5 (SST5) carrying a spontaneous R240W mutation in the third intracellular loop had a similar ability to inhibit intracellular cAMP levels to the wild-type protein but failed to mediate inhibition of growth hormone (GH) release and cell proliferation, we used this model to check specific receptor-G-protein coupling by a bioluminescent resonance energy transfer analysis. In HEK293 cells, wild-type SST5 stimulated the activation of Gα(i1-3) and Gα(oA), B, whereas R240W SST5 maintained the ability to activate Gα(i1-3) and Gα(oB), but failed to activate the splicing variant Gα(oA). To investigate the role of the selective deficit in Gα(oA) coupling, we co-transfected human adenomatous somatotrophs with SST5 and a pertussis toxin (PTX)-resistant Gα(oA) (Gα(oA(PTX-r))) protein. In PTX-treated cells, Gα(oA(PTX-r)) rescued the ability of the selective SST5 analog BIM23206 to inhibit extracellular signal-related kinase 1/2 (ERK1/2) phosphorylation, GH secretion and intracellular cAMP levels. Moreover, we demonstrated that silencing of Gα(oA) completely abolished SST5-mediated inhibitory effects on GH secretion and ERK1/2 phosphorylation, but not on cAMP levels. In conclusion, by analysing the coupling specificity of human SST5 to individual Gα(i) and Gα(o) subunits, we identified a crucial role for Gα(oA) signalling in human pituitary cells.

Role of IGF1-(CA)19 promoter microsatellite in the clinical presentation of acromegaly.

BACKGROUND: A highly polymorphic Cytosine-Adenosine (CA) repeat sequence microsatellite has been identified in the promoter region of IGF1 gene. Several studies investigated the relationship between IGF1-(CA)n polymorphism and IGF1 levels, with conflicting results. Aim of this study was to investigate the influence of this polymorphism on clinical and biochemical characteristics of acromegalic patients. METHODS: Eighty-eight acromegalic patients and 104 normal subjects were included in the study. Blood DNA was extracted and analysed by microsatellite technique using capillary electrophoresis. Patients and controls were subdivided in 19/19 [homozygous for the (CA)19 allele], 19/X [heterozygous for the (CA)19 allele] and X/X (any other genotype). RESULTS: The genotype frequency was significantly different between patients and controls, the proportion of 19/19 being lower (28·4% vs. 50·0%) and 19/X and X/X higher in acromegalic patients than in controls (P = 0·004). There were no significant differences in age, gender, basal and nadir GH, IGF1-SDS, tumour size, metabolic parameters, outcome and treatment among the three groups. The different frequency of genotypes in acromegalic patients vs. controls, as well as the lack of relationship between IGF1-(CA)n polymorphism and clinical and biochemical data in acromegalic patients, was confirmed using an additional alternative genotyping considering (CA)19 and (CA)20 homozygotes and heterozygotes vs. alleles with more than 19 of 20 repeats or less. CONCLUSIONS: Our results do not support the hypothesis that IGF-(CA)n alleles may have a significant role in determining clinical, biochemical and outcome of patients with acromegaly. The possible role of IGF1 polymorphism on susceptibility to acromegaly remains to be investigated.

Real-world sex differences in type 2 diabetes patients treated with GLP-1 receptor agonists.

AIMS: To evaluate the determinants of cardiovascular (CV) protection in men and women treated with glucagon-like peptide-1 receptor agonists (GLP1-RA). METHODS: Retrospective cohort study of 550 patients (43% women), with and without established CV disease, followed at a single center after the first prescription of a GLP1-RA. We analyzed the determinants of major adverse cardiovascular events (MACE) in men and women. RESULTS: The rate of MACE was similar between sexes. In primary prevention, among men, older age (HR 1.13, 95 % C.I. 1.05-1.22; P = 0.001) and GLP-1 RA withdrawal by time (HR 2.77, 95 % C.I. 1.15-6.68; P = 0.023) increased the HR for MACE. Among women, significant predictors of MACE were diabetes duration (HR 1.05, C.I. 1.01-1.10; P = 0.020), GLP-1 withdrawal by time (HR 2.84, 95 % C.I. 1.13-7.10; P = 0.026) and BMI at GLP-1 RA withdrawal (HR 1.08, 95 % C.I. 1.01-1.15; P = 0.026). For individuals with prior CV disease, the HR for MACE was solely impacted by GLP-1 withdrawal over time in males (HR 2.18, 95 % C.I. 1.10-4.30; P = 0.025) and by older age at GLP-1 RA initiation (HR 1.17, 95 % C.I. 1.03-1.33; P = 0.015) in females. CONCLUSIONS: Although MACE rates were similar, the factors contributing to MACE differed by sex.

COVID-19 vaccines and blood glucose control: Friend or foe?

PURPOSE: To overview the recent literature regarding the relationship between COVID-19 vaccines and glycemic control. METHODS: Data were extracted from text and tables of all available articles published up to September 2023 in PubMed Database describing glucose homeostasis data in subjects exposed to COVID-19 vaccines, focusing on patients with diabetes mellitus (DM). RESULTS: It is debated if the immune system impairment observed in diabetic patients makes them susceptible to lower efficacy of vaccines, but evidence suggests a possible improvement in immune response in those with good glycemic control. Despite their proven protective role lowering infection rates and disease severity, COVID-19 vaccines can result in diabetic ketoacidosis, new-onset diabetes, or episodes of hyper- or hypoglycemia. CONCLUSIONS: Evidence with COVID-19 vaccines highlights the strong relationship existing between DM and immune system function. Clinicians should strive to achieve optimal glucose control before vaccination and promptly manage possible glucose homeostasis derangement following vaccine exposure.

Alteration of the immunophenotype and cytokine profiles in patients affected by neuroendocrine neoplasms.

PURPOSE: Neuroendocrine neoplasms (NENs) are tumors that arise from cells of the endocrine system and are most common in the gastrointestinal tract, the pancreas, and the lungs. Their incidence is rapidly increasing and the therapeutic options available are limited. METHODS: Since the immune system can interfere with tumor growth and response to therapy, using flow cytometry we investigated the immunophenotype in samples of peripheral blood leukocytes from patients with pancreatic (Pan-NENs) and pulmonary NENs (Lung-NENs). Moreover, we performed a multiplex analysis of 13 key cytokines and growth factors essential for the immune response in the plasma of NEN patients and controls. RESULTS: Patients presented with a higher percentage of granulocytes, a lower percentage of lymphocytes, and an increase in the granulocytes to lymphocytes ratio compared to healthy donors. These alterations were more marked in patients with metastasis. Somatostatin analogs (SSAs) restored the immunophenotype of patients to that seen in healthy donors. Finally, Pan-NEN patients showed a higher plasma concentration of IP-10, MCP-1, and IL-8 compared to healthy donors, suggesting a potential role for these cytokines as diagnostic biomarkers. CONCLUSION: This study highlighted differences in the immunophenotype of patients with Pan- and Lung-NENs compared to healthy individuals; these alterations were partially restored by therapy.

DXA-derived lumbar bone strain index corrected for kyphosis is associated with vertebral fractures and trabecular bone score in acromegaly.

PURPOSE: The bone strain index (BSI) is a marker of bone deformation based on a finite element analysis inferred from dual X-ray absorptiometry (DXA) scans, that has been proposed as a predictor of fractures in osteoporosis (i.e., higher BSI indicates a lower bone's resistance to loads with consequent higher risk of fractures). We aimed to investigate the association between lumbar BSI and vertebral fractures (VFs) in acromegaly. METHODS: Twenty-three patients with acromegaly (13 males, mean age 58 years; three with active disease) were evaluated for morphometric VFs, trabecular bone score (TBS), bone mineral density (BMD) and BSI at lumbar spine, the latter being corrected for the kyphosis as measured by low-dose X-ray imaging system (EOS®-2D/3D). RESULTS: Lumbar BSI was significantly higher in patients with VFs as compared to those without fractures (2.90 ± 1.46 vs. 1.78 ± 0.33, p = 0.041). BSI was inversely associated with TBS (rho -0.44; p = 0.034), without significant associations with BMD (p = 0.151), age (p = 0.500), BMI (p = 0.957), serum IGF-I (p = 0.889), duration of active disease (p = 0.434) and sex (p = 0.563). CONCLUSIONS: Lumbar BSI corrected for kyphosis could be proposed as integrated parameter of spine arthropathy and osteopathy in acromegaly helping the clinicians in identifying patients with skeletal fragility possibly predisposed to VFs.

Looking at the spine in controlled Acromegaly.

Skeletal fragility with high risk of vertebral fractures (VFs) is an emerging complication of growth hormone (GH) hypersecretion. VFs often coexist with spine arthropathy and both clinical conditions negatively impact on quality of life of acromegalic subjects. Management of spine osteopathy and arthropathy in acromegaly could be challenging since both complications can persist or even progress after biochemical control of disease. This article analyzes the latest evidence about possible pathophysiological links between VFs and spine arthropathy in active and controlled acromegaly, as well as the diagnostic and therapeutic aspects concerning the holistic management of acromegalic osteo-arthropathy.

Low-intensity shockwave treatment (LISWT) improves penile rigidity in eugonadal subjects with erectile dysfunction: a pilot study.

BACKGROUND: Since low-intensity shockwave treatment (LISWT) has putative effects on penile hemodynamics remodeling, the aim of this study was to evaluate any improvement of penile vascular flows after LISWT treatment in patients with erectile dysfunction (ED) and poor response to PDE5i. METHODS: Twenty-one eugonadal patients with different ED severity underwent 6 weekly LISWT sessions (1500-4000 pulses) after 2 weeks withdrawal from PDE5i assumption. Once daily Tadalafil (2.5 mg daily) was reintroduced 4 weeks apart from LISWT termination and patients were evaluated at 1, 2 and 6 months follow-up (T1, T2, T6) by the International Index of Erectile Function-15 items questionnaire (IIEF-15) erectile function (EF) domain, Erection Hardness Score (EHS) and Global Assessment Questionnaires (GAQ). Basal Penile Color-Doppler Ultrasound parameters in the flaccid state (B-PCDU) were evaluated before, during and after interventional protocol. RESULTS: Mean EHS score improved in 35% of patients at T1, and in up to 50% of patients at T2 and T6 follow-up visits (P<0.05). We found 25% improvement of EF scores at T1 session, 43.75% at T2 and 62.5% at T6, respectively (P<0.05). No statistically significant differences in flow parameters, EF-domain and testosterone levels were found when baseline and last observation carried forward (LOCF) parameters were compared. The GAQ questionnaire scored higher satisfaction rates either at the end of the treatment (100%), or at LOCF (92.5%). CONCLUSIONS: Despite the study limitations with respect to B-PCDU in this setting, our results confirm a trend toward improvement of erectile questionnaire scores after LISWT with higher overall satisfaction rates among patients with ED. We conclude that LISWT may be an effective option in some difficult-to-treat patients with ED by improving the erectile response to PDE5i.

ACTH Stimulation Test for the Diagnosis of Secondary Adrenal Insufficiency: Light and Shadow.

Secondary Adrenal Insufficiency (SAI) is a condition characterized by inappropriately low ACTH secretion due to a disease or injury to the hypothalamus or the pituitary. The evaluation when suspected is often challenging for the non-specific symptoms, the rarity of the disease, and the pitfalls associated with laboratory tests. A prompt and correct diagnosis of SAI is essential because although an adequate hormonal replacement therapy could be lifesaving, inappropriate life-long therapy with steroids can be harmful. The gold standard test for assessing the hypothalamus-pituitary-adrenal axis (HPA) is the insulin tolerance test (ITT), but due to safety issues is not widely used. Conversely, the ACTH stimulation test is a safer and well-tolerated tool for SAI diagnosis. However, data about its diagnostic accuracy show great variability due to both technical and interpretative aspects, such as dose, route of administration, the timing of the test, and assay used for cortisol measurements. Consequently, the clinical background of the patient and the pretest probability of HPA axis impairment become of paramount importance. We aimed to summarize the recent literature evidence in the conduction and interpretation of the ACTH stimulation test for the diagnosis of SAI to provide updated insights on its correct use in clinical practice.

Trabecular bone score, bone marrow fat and vertebral fractures in cushing syndrome.

OBJECTIVE: Prediction of fragility fractures in Cushing syndrome (CS) is a challenge since dual energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD) does not capture all the alterations in bone microstructure induced by glucocorticoid excess. In this study we investigated the relationship between trabecular bone score (TBS), bone marrow fat (BMF) and vertebral fractures (VFs) in endogenous CS. DESIGN: Cross-sectional. METHODS: Thirty subjects (7 M and 23 F, mean age 44.8 ± 13.4 yrs, range: 25-71) with active hypercortisolism were evaluated for VFs by quantitative morphometry, BMD and TBS by lumbar spine DXA and BMF by single-voxel magnetic resonance spectroscopy of vertebral body of L3. RESULTS: Subjects with VFs (17 cases; 56.7%) had higher BMF (P = 0.014) and lower BMD T-score (P = 0.012) and TBS (P = 0.004) as compared to those without VFs. Prevalence of VFs resulted to be significantly higher in individuals with impaired TBS as compared to those with normal TBS (77.8% vs. 25.0%; P = 0.008). Among patients with VFs, only 6 (35.3%) had either osteoporosis or "low BMD for age". In logistic regression analysis, impaired TBS maintained the significant association with VFs [odds ratio (OR) 6.60, 95% C.I. 1.07-40.61; P = 0.042] independently of BMF (OR 1.03, 95% C.I. 0.99-1.08; P = 0.152). CONCLUSIONS: TBS might be more accurate than BMF in identifying subjects with active CS and skeletal fragility at risk of VFs. SIGNIFICANCE STATEMENT: Excess in glucocorticoids is associated with alterations in bone remodeling and metabolism, leading to fragility fractures regardless of bone mineral density, making more challenging for the clinician the identification of high-risk population and the definition of preventing strategies. In this context, instrumental parameters suggestive of bone quality alterations and predictive of increased fracture risk are needed. In this study, we found CS patients to have bone quality alterations as indicated by the decreased trabecular bone score and increased bone marrow fat, as measured by DEXA and MRI respectively. Both parameters were associated with high risk of VFs, and were inversely correlated, although TBS seems to be more accurate than BMF in fractures prediction in this clinical setting.

A ß-Arrestin 2-Biased Dopamine Receptor Type 2 (DRD2) Agonist Is More Efficacious Than Cabergoline in Reducing Cell Proliferation in PRL-Secreting but Not in Non-Functioning Pituitary Tumor Cells.

The molecular events underlying the variable effectiveness of dopamine receptor type 2 (DRD2) agonists in pituitary neuroendocrine tumors (PitNETs) are not known. Besides the canonical pathway induced by DRD2 coupling with Gi proteins, the ß-arrestin 2 pathway contributes to DRD2's antimitotic effects in PRL- and NF-PitNETs. A promising pharmacological strategy is the use of DRD2-biased agonists that selectively activate only one of these two pathways. The aim of the present study was to compare the effects of two biased DRD2 ligands, selectively activating the G protein (MLS1547) or ß-arrestin 2 (UNC9994) pathway, with unbiased DRD2 agonist cabergoline in PRL- and NF-PitNET cells. In rat tumoral pituitary PRL-secreting MMQ cells, UNC9994 reduced cell proliferation with a greater efficacy compared to cabergoline (-40.2 ± 20.4% vs. -21 ± 10.9%, p < 0.05), whereas the G-protein-biased agonist induced only a slight reduction. ß-arrestin 2 silencing, but not pertussis toxin treatment, reverted UNC9994 and cabergoline's antiproliferative effects. In a cabergoline-resistant PRL-PitNET primary culture, UNC9994 inhibited cell proliferation and PRL release. In contrast, in NF-PitNET primary cultures (n = 23), biased agonists did not show better antiproliferative effects than cabergoline. In conclusion, the preferential activation of the ß-arrestin 2 pathway by UNC9994 improves DRD2-mediated antiproliferative effects in PRL-PitNETs, suggesting a new pharmacological approach for resistant or poorly responsive tumors.