Growth Hormone Is Necessary for the p53-Mediated, Obesity-Induced Insulin Resistance in Male C57BL/6J × CBA Mice

Insulin resistance is a key marker of both obesity and GH excess. The purpose of the study was to assess the role of GH on p53-mediated insulin resistance of male mice with obesity due to a high-fat diet. C57BL/6J CBA male mice fed on a high-fat diet (Obe) were studied; male mice fed a normal diet (Lean) or transgenic mice for bovine GH under the same genetic background (Acro) served as controls. The convergence of p53 and GH pathways was evaluated by Western blot. Obe mice had insulin resistance, which was sustained by a selective increased expression of p53 in adipose tissue. Normal insulin sensitivity was restored, and adipose p53 expression normalized when the GH pathway was blocked. Only the adipose p53 expression was sensitive to the GH blockage, which occurred through the p38 pathway. Adipose tissue of Obe mice had a coordinate overexpres- sion of suppressors of cytokine signal 1–3 and signal transducers and activators of transcrip- tion-1, -3, and -5b, not different from that of Acro mice, suggesting an increased sensitivity of adipose tissue to GH. On the contrary, Lean mice were unaffected by changes of GH action. GH seems to be necessary for the increased adipose p53 expression and for insulin resistance of obese mice

Comparison of the effects of primary somatostatin analogue therapy and pituitary adenomectomy on survival in patients with acromegaly: a retrospective cohort study

Objective: Acromegalic patients have an increased risk of mortality. The objective of this study was to compare the effect of different therapies for acromegaly on mortality. Design and methods: The mortality rate of 438 consecutive acromegalic patients was compared with that of the general population using the standardized mortality ratio (SMR); the effect of different therapies on survival was evaluated using Cox regression analysis. Results: Twenty patients (4.5%) died between 1999 and 2009. Age- and sex-adjusted SMR was 0.70 (95% CI 0.43–1.08). The Cox regression analysis revealed that, in the whole population, both general risk factors (age and physical status) and specific factors for acromegaly (macroadenoma, hypopituitarism and uncontrolled disease) were associated with death. The most compromised patients at diagnosis had a higher mortality rate (PZ0.001), which also occurred in patients with controlled acromegaly. Death occurred in 2.4% (adenomectomy), 2.6% (adenomectomy followed by somatostatin analogue (SSA) therapy) and 11.4% (SSA therapy as the primary therapy) of the patients. The risk of death was higher in patients receiving SSA therapy as the primary therapy (hazard ratio (HR) 5.52, 95% CI 1.06–28.77, PZ0.043) than in all patients submitted to adenomectomy; however, a higher risk of death occurred only in diabetic patients treated with SSAs alone (HR 21.94, 95% CI 1.56–309.04, PZ0.022). Radiotherapy was associated with an increased risk of mortality, which occurred in patients with the more locally advanced disease. Conclusions: Therapies for acromegaly and comorbidities have lowered the risk of mortality to the level of the general population; the effect of SSA therapy alone or that following pituitary adenomectomy was comparable to that of curative neurosurgery on survival in non-diabetic patients; on the contrary, SSA therapy as the primary therapy may be less effective than adenomectomy in reducing mortality rate in diabetic patients

Diabetes mellitus induced by somatostatin analogue therapy is not permanent in acromegalic patients

CONTEXT: Therapy with somatostatin analogues (SSAs) may have deleterious effects on glucose metabolism in patients with acromegaly, often leading to the development of diabetes mellitus (DM). AIM: The aim of the study was to evaluate whether DM, developed during therapy with SSAs, may revert after drug withdrawal and cure of acromegaly with pituitary adenomectomy. DESIGN: Retrospective cohort study, in a tertiary referral centre. PATIENTS: Eighteen acromegalic patients without DM at the diagnosis of acromegaly treated with SSAs as a primary therapy, and then cured by pituitary adenomectomy. METHODS: Endocrine status and glucose homeostasis were evaluated at diagnosis of acromegaly and at least every 6 months during SSA therapy. At each visit, patients were classified into one of the following classes: normal glucose tolerance, prediabetes, overt diabetes. RESULTS: Median follow-up after starting SSAs therapy was 69 months (IQR 54.75-132.25). During SSA therapy, all patients had controlled acromegaly defined by normal serum IGF1 concentrations for the age. Of the 13 euglycaemic patients at diagnosis, three developed prediabetes and three diabetes, whereas, of the five prediabetic patients at diagnosis, two worsened to overt diabetes and three remained in the prediabetic range (P = 0.04). After curing acromegaly with pituitary adenomectomy and subsequent SSA withdrawal, prediabetes reverted in five of six patients, and diabetes in all five patients (three reverted to euglycaemia, while two reverted to prediabetes) (P = 0.01). CONCLUSIONS: In acromegalic patients with controlled disease, changes in glycaemic status induced by SSAs are not permanent

Divergent effects of dioxin- or non- dioxin- Like polychlorinated biphenyls on the apoptosis of primary cell culture from the mouse dioxin pituitary gland

Polychlorinated biphenyls (PCBs) can disrupt the endocrine function, promote neoplasms and regulate apoptosis in some tissues; however, it is unknown whether PCBs can affect the apoptosis of pituitary cells. The study evaluated the effect of PCBs on the apoptosis of normal pituitary cells and the underlying mechanisms. Primary cell cultures obtained from mouse pituitary glands were exposed to Aroclor 1254 or selected dioxin-like (PCB 77, PCB 126) or non-dioxin-like (PCB 153, PCB 180) congeners. Apoptosis was evaluated by Annexin V staining, DNA fragmentation, and TUNEL assay. Both the expression and activity of caspases were analyzed. Selective thyroid hormone receptor (TR) or aryl-hydrocarbon receptor (AhR) or CYP1A1 antagonist were used to explore the mechanisms underlying PCBs action. Our results showed that Aroclor 1254 induced the apoptosis of pituitary cells as well as the final caspase-3 level and activity through the extrinsic pathway, as shown by the increased caspase-8 level and activity. On the other hand, the intrinsic pathway evaluated by measuring caspase-9 expression was silent. The selected non-dioxin- like congeners either increased (PCB 180) or reduced (PCB 153) pituitary cell apoptosis, affecting the extrinsic pathway (PCB 180), or both the extrinsic and intrinsic pathways (PCB 153), respectively. In contrast, the dioxin-like congeners (PCB 77 and PCB 126) did not affect apoptosis. The anti-apoptotic phenotype of PCB 153 was counteracted by a TR or a CYP1A1 antagonist, whereas the pro-apoptotic effect of PCB 180 was counteracted by an AhR antagonist. The induced apoptosis of Aroclor 1254 or PCB 180 was associated with a reduction of cell proliferation, whereas the decreased apoptosis due to PCB 153 increased cell proliferation by 30%. In conclusion, our data suggest that non-dioxin-like PCBs may modulate apoptosis and the proliferation rate of pituitary cells that have either pro- or anti-apoptotic effects depending on the specific congeners. However, the impact of PCBs on the process of pituitary tumorigenesis remains to be elucidated

DISEASE ACTIVITY AND LIFESTYLE INFLUENCE COMORBIDITIES AND CARDIOVASCULAR EVENTS IN PATIENTS WITH ACROMEGALY

Objective: The primary objective of this study is to identify the predictors of comorbidities and major adverse cardiovascular events (MACE) that can develop after diagnosis of acromegaly. The role of therapy for acromegaly in the event of such complications was also evaluated. Design and methods: Retrospective cohort study was conducted on 200 consecutive acromegalic patients in a tertiary referral center. The following outcomes were evaluated: diabetes, hypertension and MACE. Each patient was included in the analysis of a specific outcome, unless they were affected when acromegaly was diagnosed, and further classified as follows: (i) in remission after adenomectomy (Hx), (ii) controlled by somatostatin analogues (SSA) (SSAc) or (iii) not controlled by SSA (SSAnc). Data were evaluated using Cox regression analysis. Results: After diagnosis of acromegaly, diabetes occurred in 40.8% of patients. The SSAnc group had a three-fold higher risk of diabetes (HR: 3.32, P = 0.006), whereas the SSAc group had a 1.4-fold higher risk of diabetes (HR: 1.43, P = 0.38) compared with the Hx group. Hypertension occurred in 35.5% of patients, after diagnosis. The determinants of hypertension were age (HR: 1.06, P = 0.01) and BMI (HR: 1.05, P = 0.01). MACE occurred in 11.8% of patients, after diagnosis. Age (HR: 1.09, P = 0.005) and smoking habit (HR: 5.95, P = 0.01) were predictors of MACE. Conversely, therapy for acromegaly did not influence hypertension or MACE. Conclusion: After diagnosis of acromegaly, control of the disease (irrespective of the type of treatment) and lifestyle are predictors of comorbidities and major adverse cardiovascular events