Prognostic significance of the Ki-67 labeling index in growth hormone-secreting pituitary adenomas.

CONTEXT: Ki-67 is a marker of proliferation activity associated with invasiveness and prognosis in human tumors. OBJECTIVE: The aim of the study was to evaluate the Ki-67 index prognostic relevance in a group of acromegalic patients who underwent transsphenoidal surgery for a GH-secreting pituitary adenoma. MATERIAL AND METHODS: We selected 68 consecutive acromegalic patients referred to our hospital during a 5-yr period. The Ki-67 index was determined by immunohistochemistry on tissue samples obtained from each adenoma after surgery. Those patients who were not completely cured after surgery began medical therapy with somatostatin analogs (SSAs). Periodical pituitary magnetic resonance imaging and hormonal evaluation were performed during the follow-up. RESULTS: Twenty-eight of 68 patients were cured after surgery (41%). Among the 40 patients treated with SSAs, 13 were considered uncontrolled. Pituitary magnetic resonance imaging showed residual/recurrent disease in 25 of 68 patients after 6 months. No correlation was found between Ki-67 index and age, tumor size, GH, or IGF-I plasma levels. Tumors described as having cavernous sinus invasion had a higher mean Ki-67 index as compared with noninvasive tumors (P < 0.01). The Ki-67 index was significantly lower in tumors in patients cured after surgery as compared with patients considered not cured (P < 0.01) and in tumors in patients controlled by SSA therapy as compared with patients considered as uncontrolled (P < 0.05). CONCLUSION: The Ki-67 labeling index may predict clinical outcome in postsurgical management of acromegalic patients. We suggest routine Ki-67 evaluation in GH-secreting pituitary adenomas.

Coenzyme Q10 evaluation in pituitary-adrenal axis disease: preliminary data.

In previous works we have demonstrated plasma CoQ10 alterations in pituitary diseases, such as acromegaly or secondary hypothyroidism. However, pituitary lesions can induce complex clinical pictures due to alterations of different endocrine axes controlled by pituitary itself. A further rationale for studying CoQ10 in pituitary-adrenal diseases is related to the common biosynthetic pathway of cholesterol and ubiquinone. We have therefore assayed plasma CoQ10 levels in different conditions with increased or defective activity of pituitary-adrenal axis (3 subjects with ACTH-dependent adrenal hyperplasia, 2 cases of Cushing's disease and 1 case of 17-alpha-hydroxylase deficiency; 10 subjects with secondary hypoadrenalism, including three subjects with also secondary hypothyroidism). CoQ10 levels were significantly lower in isolated hypoadrenalism than in patients with adrenal hyperplasia and multiple pituitary deficiencies (mean +/- SEM: 0.57 +/- 0.04 vs 1.08 +/- 0.08 and 1.10 +/- 0.11 microg/ml, respectively); when corrected for cholesterol levels, the same trend was observed, but did not reach statistical significance. These preliminary data indicate that secretion of adrenal hormones is in some way related to CoQ10 levels, both in augmented and reduced conditions. However, since thyroid hormones have an important role in modulating CoQ10 levels and metabolism, when coexistent, thyroid deficiency seems to play a prevalent role in comparison with adrenal deficiency.

Growth hormone secretion and leptin in morbid obesity before and after biliopancreatic diversion: relationships with insulin and body composition.

Obesity is characterized by increased leptin levels and insulin resistance, whereas blunted GH secretion is paired with normal, low, or high plasma IGF-I levels. To investigate body composition in human obesity and the interactions among the GH-IGF-I axis, leptin, and insulin resistance [measured with the homeostasis model assessment (HOMA) score], we studied 15 obese females, aged 23-54 yr (mean age, 42.7 +/- 2.6), with a body mass index (BMI) of 44.02 +/- 1.45 kg/m(2), who underwent treatment by biliopancreatic diversion (BPD), before and after surgery (16-24 months; BMI, 28.29 +/- 0.89 kg/m(2)). Our controls were 15 normal females, aged 28-54 yr (mean age, 40.8 +/- 2.3 yr), with a BMI of 27.52 +/- 0.53 kg/m(2). Insulin and leptin levels and HOMA scores were higher pre-BPD than in the controls. The GH response to GHRH was blunted, with a GH peak and GH area under the curve (AUC) significantly lower than those in controls. IGF-I and IGF-binding protein-3 (IGFBP-3) were also lower than control values. After surgery, BMI, fat mass, lean body mass, HOMA, insulin, and leptin significantly decreased. Furthermore, the GH response to GHRH severely increased; IGF-I and IGFBP-3 levels did not significantly vary. Considering all subjects, correlation analysis showed a strong positive correlation between insulin and leptin, and a negative correlation between insulin and GH peak and between insulin and GH AUC. Regression analysis performed grouping pre- and post-BPD indicated that leptin and GH peak or AUC could best be predicted from insulin levels. The surgical treatment of severe obesity after stabilization of body weight decreases BMI and fat mass while preserving normal lean body mass as well as positively influencing insulin sensitivity and thus aiding the normalization of leptin levels. The insulin reduction may be mainly involved in the increase in the GH response to GHRH through various possible central and peripheral mechanisms while decreasing the peripheral sensitivity to GH itself, as shown by the stable nature of the IGF-I and IGFBP-3 values. Our findings suggest that the changes in insulin levels are the starting point for changes in both leptin levels and the somatotrope axis after BPD.

High prevalence of hyperplastic colonic polyps in acromegalic subjects.

We evaluated the prevalence and features of colonic polyps in a population of acromegalic subjects, compared to a control group of patients with irritable bowel syndrome (IBS). Colonic polyps were found in 30 acromegalic subjects (40%) and in 10 controls (13%) (P < 0.0001). Among the acromegalic patients, polyps were of the hyperplastic type in 27 subjects (90%) and adenomatous in 3 (10%). In the control group, polyps were hyperplastic in nine subjects (90%) and adenomatous in one (10%). We also observed a significant association (P < 0.0001) between the presence of hyperplastic polyps and the older age in both the acromegalic and the control groups. There were no differences between the two groups regarding sex, site, size, or macroscopic and histological types of polyps. Acromegalic patients have a higher prevalence of colonic hyperplastic polyps than IBS subjects, while the prevalence of adenomatous polyps is similar in the two groups.