Survivin: A Potential Marker of Resistance to Somatostatin Receptor Ligands.

CONTEXT: Invasive and somatostatin receptor ligand (SRL)-resistant pituitary tumors represent a challenge in the clinical practice of endocrinologists. Efforts have been made to elucidate reliable makers for both. Survivin and eukaryotic translation initiation factor-binding protein 1 (4EBP1) are upregulated in several cancers and involved in apoptosis and cell proliferation. OBJECTIVE: We explored the role of these markers in somatotropinomas. METHODS: Immunostains for survivin and 4EBP1, and also for somatostatin receptor type 2 (SSTR2), Ki-67, and cytokeratin 18, were analyzed in tissue microarrays containing 52 somatotropinoma samples. Tumor invasiveness was evaluated in all samples while drug resistance was evaluated in 34 patients who received SRL treatment. All these parameters were correlated with first-generation SRL (fg-SRL) responsiveness and tumor invasiveness. RESULTS: Low survivin expression (P = 0.04), hyperintense signal on T2 weighted image (T2WI) (P = 0.01), younger age (P = 0.01), sparsely granular adenomas (SGA) (P = 0.04), high postoperative growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels (P = 0.049 and P < 0.001, respectively), and large postoperative tumor size (P = 0.02) were associated with resistance to fg-SRL. Low survivin and SSTR2 expression and high 4EBP1 expression were associated with SGA (P = 0.04, P = 0.01, and P = 0.001, respectively). Younger age (P = 0.03), large tumor pre- and postoperative (P = 0.04 and P = 0.006, respectively), low SSTR2 expression (P = 0.03), and high baseline GH and IGF-1 (P = 0.01 and P = 0.02, respectively) were associated with tumor invasiveness. However, survivin, 4EBP1, Ki-67, and granulation patterns were not associated with tumor invasion. CONCLUSION: This study suggests that low survivin expression is predictive of resistance to fg-SRL in somatotropinomas, but not of tumor invasiveness.

Impaired Bone Microarchitecture in Premenopausal Women With Acromegaly: The Possible Role of Wnt Signaling.

CONTEXT: Acromegaly can impair bone integrity, increasing the risk of vertebral fractures (VFs). OBJECTIVE: To evaluate the impact of isolated GH/IGF-I hypersecretion on bone turnover markers, Wnt inhibitors, bone mineral density (BMD), microarchitecture, bone strength and vertebral fractures in female patients with acromegaly (Acro), compared with healthy control group (HC). DESIGN, SETTING, AND PATIENTS: Cross-sectional study including 83 premenopausal women without any pituitary deficiency:18 acromegaly in remission (AcroR), 12 in group with active acromegaly (AcroA), and 53 HC. Serum procollagen type 1 N-terminal propeptide, ß-carboxy-terminal crosslinked telopeptide of type 1 collagen, osteocalcin, sclerostin, and DKK1 were measured in blood samples. dual-energy X-ray absorptiometry, high-resolution peripheral quantitative computed tomography (HR-pQCT) and vertebral fractures evaluation were also assessed simultaneously. MAIN OUTCOME AND RESULTS: AcroA showed significantly lower sclerostin and higher DKK1 compared with HC. On HR-pQCT of tibia and radius, Acro showed impairment of trabecular (area and trabecular number), increased cortical porosity, and increased cortical area and cortical thickness compared with HC. The only significant correlation found with HR-pQCT parameters was a positive correlation between cortical porosity and serum DKK1 (R = 0.45, P = 0.044). Mild VFs were present in approximately 30% of patients. CONCLUSIONS: Eugonadal women with acromegaly without any pituitary deficiency showed increased cortical BMD, impairment of trabecular bone microstructure, and increased VF. Sclerostin was not correlated with any HR-pQCT parameters; however, DKK1 was correlated with cortical porosity in tibia (P = 0.027). Additional studies are needed to clarify the role of Wnt inhibitors on bone microarchitecture impairment in acromegaly.

Bone microarchitecture and estimated bone strength in men with active acromegaly.

CONTEXT: Both acromegaly and adult growth hormone deficiency (GHD) are associated with increased fracture risk. Sufficient data are lacking regarding cortical bone microarchitecture and bone strength, as assessed by microfinite element analysis (µFEA). OBJECTIVE: To elucidate both cortical and trabecular bone microarchitecture and estimated bone strength in men with active acromegaly or GHD compared to healthy controls. DESIGN AND SUBJECTS: Cross-sectional study at a clinical research center, including 48 men (16 with acromegaly, 16 with GHD and 16 healthy controls). OUTCOME MEASURES: Areal bone mineral density (aBMD), cortical and trabecular bone microarchitecture and estimated bone strength (µFEA) at the radius and tibia. RESULTS: aBMD was not different between the 3 groups at any skeletal site. At the radius, patients with acromegaly had greater cortical area (P < 0.0001), cortical thickness (P = 0.0038), cortical pore volume (P < 0.0001) and cortical porosity (P = 0.0008), but lower trabecular bone density (P = 0.0010) compared to controls. At the tibia, patients with acromegaly had lower trabecular bone density (P = 0.0082), but no differences in cortical bone microstructure. Compressive strength and failure load did not significantly differ between groups. These findings persisted after excluding patients with hypogonadism. Bone microarchitecture was not deficient in patients with GHD. CONCLUSIONS: Both cortical and trabecular microarchitecture are altered in men with acromegaly. Our data indicate that GH excess is associated with distinct effects in cortical vs trabecular bone compartments. Our observations also affirm the limitations of aBMD testing in the evaluation of patients with acromegaly.

Predictors of Hypopituitarism in Patients with Traumatic Brain Injury.

Hypopituitarism may often occur in association with traumatic brain injury (TBI). Identification of reliable predictors of pituitary dysfunction is of importance in order to establish a rational testing approach. We searched the records of patients with TBI, who underwent neuroendocrine evaluation in our institution between 2007 and 2013. One hundred sixty-six adults (70% men) with TBI (median age: 41.6 years; range: 18-76) were evaluated at a median interval of 40.4 months (0.2-430.4).Of these, 31% had ≥1 pituitary deficiency, including 29% of patients with mild TBI and 35% with moderate/severe TBI. Growth hormone deficiency was the most common deficiency (21%); when body mass index (BMI)-dependent cutpoints were used, this was reduced to 15%. Central hypoadrenalism occurred in10%, who were more likely to have suffered a motor vehicle accident (MVA, p = 0.04), experienced post-traumatic seizures (p = 0.04), demonstrated any intracranial hemorrhage (p = 0.05), petechial brain hemorrhages (p = 0.017), or focal cortical parenchymal contusions (p = 0.02). Central hypothyroidism occurred in 8% and central hypogonadism in 12%; the latter subgroup had higher BMI (p = 0.03), were less likely to be working after TBI (p = 0.002), and had lower Global Assessment of Functioning (GAF) scores (p = 0.03). Central diabetes insipidus (DI) occurred in 6%, who were more likely to have experienced MVA (p < 0.001) or sustained moderate/severe TBI (p < 0.001). Patients with MVA and those with post-traumatic seizures, intracranial hemorrhage, petechial brain hemorrhages, and/or focal cortical contusions are at particular risk for serious pituitary dysfunction, including adrenal insufficiency and DI, and should be referred for neuroendocrine testing. However, a substantial proportion of patients without these risk factors also developed hypopituitarism.