Detection of small bowel tumors by videocapsule endoscopy in patients with acromegaly

The prevalence of colon polyposis andmalignancies is increased in acromegalic patients as compared to the general population. An epidemiological study suggests a high prevalence also of small bowel (SB) tumors that nowadays may be detected by videocapsule endoscopy (VCE). The aim of the study was to assess the prevalence of SB neoplasms using VCE in acromegalic patients in comparison to control subjects and to correlate it with cancer risk factors and acromegaly-related parameters. Eighteen acromegalic patients (6 males and 12 females, age+/-SD: 54+/-10 yr), 5 cured after surgery (followed by radiotherapy in 3 cases) and 13 on pharmacological treatment were enrolled, and 36 sex- and age-matched non-acromegalic subjects served as a control group. Cancer risk factors, duration of acromegaly, GH and IGF-I levels, IGF binding protein 3 and IGF-II concentrations, metabolic parameters, tumor markers, colonic lesions by total colonoscopy, and SB lesions by VCE were investigated. VCE images suggestive of SB lesions were detected in 5/36 controls [14%, 4 described as gastrointestinal stromal nodular tumors (GIST), and 1 as polyp] and in 5/18 acromegalic patients [28%, 2 GIST and 3 polyps]. In acromegaly, the calculated relative risk for all SB lesions was 1.69 [95%confidence interval (CI): 0.78-3.65], while the relative risk for SB polyps was 2.50 (95% CI: 1.23-5.07). The effective duration of active disease was longer in patients with positive than in those with negative VCE (112+/-89 vs 49+/-40 months, p=0.06). In conclusion, these preliminary results suggest that acromegalic patients might have a high risk of SB polyp development. VCE might be a useful adjunctive diagnostic tool in acromegaly.

Ultrasound-guided laser thermal ablation for parathyroid adenomas: analysis of three cases with a three-year follow-up

BACKGROUND

In patients with primary hyperparathyroidism (pHPT) the therapeutical choice is surgery. In patients with high surgical and anesthetic risks, ultrasound-guided laser ablation (LTA) of parathyroid adenoma has been reported to reduce parathyroid hormone (PTH) hypersecretion without relevant side effects. No data are available from patients followed for >6 months. We report our 3-year follow-up experience with LTA in 3 patients affected by pHPT due to a parathyroid tumor.

METHODS

LTA was performed under color-Doppler ultrasound guidance with a continuous pulse at 2 W (total treatment duration: 300 s in each session; total energy: 1,200 J in two sessions).

RESULTS

In the first patient who refused to undergo the second LTA session, calcium, PTH levels and parathyroid lesion volume showed a slight reduction, returning to baseline values in a month. In the second patient, no modification of parathyroid lesion was obtained even if calcium levels temporarily normalized. In the third patient, LTA led to normalization of calcium and PTH levels and to a 99% reduction of parathyroid volume.

CONCLUSION

After LTA procedures the long-term disease remission of pHPT is achievable in a minority of patients. Data from larger samples are needed to verify the usefulness of this procedure.

New therapeutic options for acromegaly

Acromegaly is a slowly developing disfiguring disease characterized by chronic growth hormone (GH) and insulin-like growth factor-I (IGF-I) excess and caused by a pituitary somatotroph adenoma. It is associated to 2- to 3 fold increased mortality, compared to normal population, mostly due to cardiovascular and cerebro-vascular diseases, and to several co-morbid systemic illnesses, such as diabetes mellitus, hypertension, severe arthropathies, a specific cardio-myopathy, goitre, sleep-apnoea, intractable headache. The morbidity and excess mortality of acromegaly are usually the consequence of the metabolic actions of excess GH and IGF-I secretion, while only in rare patients mortality is due to the mass effects of the pituitary tumour. Since, serum IGF-I concentrations within age-adjusted normal range, and a tight GH control have to be achieved to normalize life-expectancy in these patients, an aggressive, and often multi-modality treatment is required for acromegaly. In recent years, new drugs, and new formulations of old drugs, have been developed that are able to effectively inhibit GH secretion or GH action, and may represent important adjuncts or even alternatives to the traditional approaches of surgery and radiotherapy. This review briefly summarizes the therapeutic options nowadays available for acromegaly. A brief note about innovative drugs under study, is also given.

Evaluation of cardiac structure by echoreflectivity analysis in acromegaly: effects of treatment

OBJECTIVES

Cardiac echoreflectivity is a noninvasive tool for evaluating cardiac fibrosis. The present paper aimed to study the modifications of cardiac echoreflectivity in a group of acromegalic patients before and after therapy, and to assess possible correlations with serum levels of procollagen III (PIIINP), a peripheral index of collagen synthesis.

DESIGN AND METHODS

Cardiac echoreflectivity (as assessed by analyzing 2-D echocardiograms digitized off-line onto a personal computer) and PIIINP levels were evaluated in 16 acromegalic patients of new diagnosis not affected by arterial hypertension (10 males, six females, age+/-s.d.: 38+/-10 years), and in a group of 16 sex- and age-matched healthy subjects. All the patients were re-evaluated after surgical and/or medical therapy for acromegaly. The echo patterns were analyzed by software that supplies the derived collagen volume fraction (dCVF), an index of fibrosis.

RESULTS

At baseline, acromegalic patients showed significantly higher dCVF values and PIIINP levels than healthy controls (3.1+/-0.5% vs 1.6+/-0.3%, P<0.01 and 8.7+/-2.2 vs 3.1+/-1.1 ng/ml, P<0.05, respectively, by unpaired Student's t-test). After therapy, dCVF and PIIINP levels normalized in the six controlled patients (that is, GH of <2.5 microg/l and IGF-I within normal range) (dCVF from 2.8+/-0.4% to 1.4+/-0.2%, P<0.001; PIIINP from 8+/-2.7 to 3.3+/-1.9 ng/ml, P<0.05), while no significant changes were found in noncontrolled patients (dCVF from 3.3+/-0.6% to 2.9+/-1.2% and PIIINP from 9.1+/-1.9 to 7.9+/-3.5 ng/ml, P=NS). A positive correlation between dCVF and PIIINP (r=0.75, P<0.001) and between IGF-I and both dCVF and PIIINP (r=0.65 and 0.61 respectively, P<0.05) was found in acromegalic patients.

CONCLUSIONS

Cardiac echoreflectivity, which may be a reflection of heart collagen content, is increased in patients with active acromegaly and correlates with PIIINP concentrations. After cure or adequate control of the disease, both parameters revert to normal. Echoreflectivity analysis could be a useful adjuvant parameter in the assessment of the activity of acromegalic disease.

Ghrelin administration affects circulating pituitary and gastro-entero-pancreatic hormones in acromegaly

OBJECTIVE

Ghrelin, a gut-brain peptide involved in the control of energy homeostasis, affects antero-pituitary and gastro-entero-pancreatic (GEP) hormone secretion in healthy subjects. We aimed to verify whether such hormonal responses are retained in acromegaly, a disease characterized by high GH, subnormal ghrelin and abnormal GEP hormone levels.

DESIGN AND METHODS

The effect of ghrelin (3.3 microg/kg given after overnight fasting as an i.v. bolus) on GH, prolactin (PRL), adrenocorticotropin (ACTH), cortisol, insulin, glucose, total somatostatin (SS) and pancreatic polypeptide (PP) circulating levels were evaluated in seven non-diabetic patients with newly diagnosed acromegaly and in nine healthy controls.

RESULTS

Ghrelin elicited a prompt, marked increase of serum GH and PRL levels in all normal (from 1.6+/-0.6 to 52.9+/-7.8 and from 9.7+/-0.8 to 24.2+/-4.8 microg/l (means+/-S.E.M.), respectively) and acromegalic subjects (from 11.2+/-4.9 to 91.6+/-21.0 and from 42.9+/-26.1 to 113.8+/-79.0 microg/l, respectively). Both plasma ACTH and serum cortisol levels rose significantly in the controls, whereas the cortisol response was blunted in the acromegalic patients. Glucose levels rose earlier and insulin levels fell later in all subjects, with a significantly greater net insulin decrease in acromegalic than in healthy subjects (-80+/-21 vs -17+/-4 pmol/l, P<0.01). A prompt PP rise and a biphasic SS response occurred in all controls, whereas in the acromegalic group the PP response (from 26.1+/-5.0 to 92.2+/-39.0 pmol/l) and the SS response (from 11.9+/-3.0 to 19.7+/-4.0 ng/l) were quite variable.

CONCLUSIONS

Ghrelin affects both pituitary and GEP hormones in acromegalic patients as in normal subjects. These findings suggest that ghrelin actions on the energy balance are mediated by complex interactive endocrine loops that involve also the gut and pancreas.

Evaluation of insulin resistance in acromegalic patients before and after treatment with somatostatin analogues

Many studies have recently shown that simple computer-solved indices, based on fasting glucose and insulin levels, closely mirror the euglycemic clamp technique in studying insulin resistance or pancreatic insulin secretion. Few data are at present available on the evaluation of these novel indices in acromegalic patients, known to be GH-dependent insulin-resistant subjects, in particular during medical treatment with somatostatin analogues. Indeed, these drugs are able to inhibit not only GH and IGF-I levels, but also insulin and glucagon pancreatic secretion, with contrasting effects on glucose metabolism. In this study, insulin resistance was evaluated by the homeostasis model assessment (HOMA-IR) and insulin sensitivity by quantitative insulin check index (QUICKI) in 27 normoglycemic acromegalic patients, before and after 6-month therapy with somatostatin analogues (lanreotide-SR 30-60 mg every 7-28 days in 15 and octreotide-LAR 20-30 mg every 28 days in 12). Thirty-five age- and sex-matched healthy subjects and 17 surgically treated acromegalic patients (5 cured and 12 not cured) were studied as control groups. Before medical treatment, HOMA-IR was higher in acromegalic patients than in healthy controls (4 +/- 3 vs 1.7 +/- 0.7, p < 0.05), while QUICKI was lower (0.33 +/- 0.04 vs 0.36 +/- 0.03, p < 0.05). During medical therapy, HOMA-IR decreased to 2.4 +/- 1.6 (p < 0.05) and became similar to that recorded in both healthy subjects and surgically treated patients. However, fasting glucose was increased and fasting insulin was decreased. QUICKI did not significantly change from basal values. No differences were observed between patients who normalized or not hormonal levels. The effects of the 2 drugs, though higher glucose levels were seen in patients treated with octreotide-LAR. In conclusion, this study demonstrates that medical treatment is able to improve insulin resistance, even if only successful surgery is able to completely normalize both HOMA-IR and QUICKI.

Elevated circulating somatostatin levels in acromegaly

GH increases hypothalamic somatostatin (SS) synthesis and secretion but it is unknown if chronic GH excess, as found in acromegaly, may influence circulating SS levels, that are mainly of enteropancreatic source and affect several gastrointestinal functions, including motility. Circulating SS occurs in several post-translational forms including somatostatin-14 (SS-14), somatostatin-28 (SS-28) and other small peptides. The aim of the present study was to characterize the fasting and postprandial pattern of plasma circulating somatostatin in normal subjects and patients with acromegaly. Fasting total SS and SS-28 levels were measured in 32 subjects, 16 acromegalic patients with a new diagnosis (A) (8 F, 8 M, median age 48) and 16 matched healthy volunteers (C) (8 F, 8 M, median age 45). SS was also determined after a standard solid-liquid meal (550 kCal) in 24 of the subjects (12 C and 12 A). Fasting SS and SS-28 were significantly higher in acromegalic patients as compared to healthy subjects. In the former, a positive correlation was found between IGF-I and SS levels (r = 0.525 p < 0.05). Furthermore, the ratio between SS (as pmol equivalent SS-14/I) and SS-28 was higher in the acromegalic patients than in the controls (3.4 +/- 2.1 vs 2.0 +/- 1.6, p < 0.05). The postprandial SS peak, as well as the incremental area above baseline values, was similar in the patients and controls. In conclusion, fasting but not postprandial hypersomatostatinemia, mainly due to an increase in SS-14, characterizes acromegaly. Excess GH/IGF-I could be a causal factor in somatostatin hypersecretion. Conceivably this abnormality might play a role in some alterations of gastrointestinal function of acromegalic patients such as prolonged bowel transit.

Therapy for the syndromes of GH excess

This short review summarizes the results of treatments now available in Italy for the management of GH and IGF-I excess due to primary pituitary somatotroph adenoma, which accounts for over 99% of cases of acromegaly. Goals of treatment of acromegaly should now include, in addition to the reduction of tumor bulk and symptomatic relief, the lowering of GH circulating concentrations to below a critical level (2.5 microg/l, "safe" GH), the normalization of serum IGF-I concentrations according to age, improvement (or at least not worsening) of co-morbidities (diabetes mellitus, hypertension, cardiomyopathy, sleep-apnea), the decrease of the risk of premature mortality. Surgery, radiation (fractionated conventional radiotherapy and radiosurgery) and medical treatments with dopamine agonists and somatostatin analogs are the available options that are discussed in detail. The treatment of acromegaly must be tailored to the needs of the individual patient. Age, tumor size and invasiveness, GH concentrations, the patient's general medical conditions, presence and severity of co-morbidities, availability of local resources such as an expert neurosurgeon or gamma-knife radiosurgery, and of course the informed wishes of the patient are all factors that must be taken into account. For most patients the treatment will be multimodal. However, despite criteria and guidelines based on continuously emerging information about the management of acromegaly, patient outcomes are still less than desirable, with 10 to 20% of patients with uncontrolled disease, despite the use of all available therapies. This underscores the need for the quick introduction in clinical practice of the new therapies.

Effects of two different somatostatin analogs on glucose tolerance in acromegaly

Impaired glucose tolerance is present in many acromegalic patients and treatment with somatostatin analogs has variable effects on glycemic control. The aim of this study was to compare the effects of 2 somatostatin analogs on glucose metabolism, lanreotide slow release (L-SR) and octreotide long acting release (O-LAR), in 10 patients with acromegaly (2 of whom with overt Type 2 diabetes mellitus). Glucose and insulin levels in fasting conditions and in response to OGTT, evaluated as AUC, insulin resistance (IR) evaluated by homeostatic model assessment (HOMA-IR), glycosylated hemoglobin (HbA1c), GH, IGF-I, were assessed during L-SR and O-LAR treatment. Mean fasting glucose, glucose response to OGTT and HbA1c levels in 8 non-diabetic patients did not significantly change after L-SR therapy while they all increased after O-LAR treatment (p<0.05 vs baseline and L-SR). Mean HOMA-IR values calculated in acromegalic patients before medical therapy were higher than in normal subjects (p<0.005) and showed a significant decrease during both treatments (p<0.05). In the 2 diabetic acromegalic patients a worsening in glucose metabolism was observed during O-LAR treatment but not during L-SR. GH and IGF-I levels significantly decreased with both drugs and normalized respectively in 38% and 12% with L-SR, 50% and 25% with O-LAR. In conclusion, both drugs decreased IR in acromegalic patients; O-LAR seems to be more detrimental to glucose metabolism than L-SR, despite being more effective in reducing GH and IGF-I levels.

Efficacy of radiotherapy in normalizing serum IGF-I, acid-labile subunit (ALS) and IGFBP-3 levels in acromegaly

OBJECTIVE

Radiotherapy (RT) has been used for many years in order to complete the cure of unsuccessfully operated acromegalic patients. Several studies have shown its efficacy in normalizing GH levels, while reports about IGF-I normalization are conflicting. Moreover, data regarding other markers of disease activity, such as IGFBP-3 and acid-labile subunit (ALS), i.e. the other two components of the circulating 150 kDa complex, are lacking.

DESIGN

Retrospective study.

PATIENTS AND MEASUREMENTS

Sixty-seven acromegalic patients (20 males and 47 females, aged 40 +/- 6 years) who underwent postoperative RT (in fractionated doses for a total of 40-75 Gy) were followed-up for 11 +/- 6 years (range: 1-26 years, median: 10 years). Serum GH and IGF-I levels off medical therapy were measured in all patients; ALS and IGFBP-3 were measured in 11 patients with normalization of IGF-I concentrations. Computed tomography or nuclear magnetic resonance imaging periodically assessed possible development of pituitary deficiency along with imaging of the hypothalamic-pituitary region.

RESULTS

Forty-one out of 67 patients (58%) achieved GH levels < 2.5 microg/l by 1-15 years after RT (mean 8 +/- 6) and 37/67 patients (55%) had normal or low IGF-I levels 1-26 years after RT (mean: 12 +/- 6), a normalization of both parameters being seen in 37 patients. GH < 2.5 microg/l and normal IGF-I levels were achieved in 17/26 (65%) patients followed-up for at least 15 years. ALS and IGFBP-3 concentrations paralleled IGF-I levels in all patients studied. With respect to secondary pituitary insufficiency, acquired ACTH deficiency was found in 25 patients, TSH deficiency in 20, gonadotropin deficiency in 23 and GH deficiency in seven. In total, two cases of meningioma and one pineal tumour, possibly related to RT, were seen 9-22 years after RT.

CONCLUSIONS

RT is an effective, although slow-acting, therapeutic tool for acromegaly, with 'safe' GH levels and normal IGF-I concentrations being achieved in 65% of patients after 15 years. IGF-I levels normalize more slowly than GH levels. Radiotherapy is able to normalize the concentration of all three components of the circulating 150 kDa complex. Checks for loss of pituitary function and appearance of second brain tumours must be carried out life-long.

Increased glucose-dependent insulinotropic polypeptide (GIP) secretion in acromegaly

OBJECTIVE

Acromegaly is often associated with fasting and postprandial hyperinsulinemia, and the mechanisms involved are only partly understood. Hypersecretion of incretins such as glucose-dependent insulinotropic polypeptide (GIP) could play a role in determining hyperinsulinemia in acromegaly, but the available data are inconsistent. The aim of this study was to characterize the fasting and postprandial pattern of plasma GIP and insulin in a group of acromegalic patients.

DESIGN AND METHODS

Eleven non-diabetic patients with newly diagnosed acromegaly and 11 sex- and age-matched healthy subjects were studied. Blood samples were taken at regular intervals in fasting conditions and for 3 h after a standard solid-liquid meal for growth hormone (GH), GIP and insulin measurements.

RESULTS

Not only insulin, but also fasting and postprandial GIP levels were significantly higher in the patients with acromegaly than the healthy subjects (P<0.01). In the former group fasting GIP levels and the integrated GIP response to the meal correlated significantly with GH basal levels (r=0.83, P<0.01 and r=0.65, P<0.05, respectively). Moreover, multivariate linear regression analysis showed that the presence of acromegalic status was associated with higher fasting and postprandial GIP levels independently of sex, age, fasting and postprandial plasma glucose and insulin levels, and the occurrence of normal or impaired glucose tolerance.

CONCLUSION

This study provides evidence that in patients with acromegaly fasting and postprandial GIP levels are abnormally high. GIP hypersecretion in turn might play a role in the pathogenesis of hyperinsulinemia that characterizes acromegaly.

Alterations of haemostatic and fibrinolytic markers in adult patients with growth hormone deficiency and with acromegaly

Alterations of coagulation and fibrinolytic systems might contribute to the increased cardiovascular and cerebrovascular mortality observed in patients with both chronic growth hormone (GH) excess (acromegaly) and deficiency (GHD). However, contrasting results have been so far reported. To assess the importance of GH in modulating haemostatic system, several haemostatic variables in patients with GHD and acromegaly were measured. Twenty-four adult patients with GHD (8 childhood- and 16 adult-onset; age: 41+/-12 years, insulin like growth factor-I, IGF-I: 6.7+/-4 nmol/L), 10 non-diabetic acromegalic patients (age: 39+/-15 years; IGF-I: 109+/-37 nmol/L) and 64 healthy volunteers age- and sex-matched with cases were studied. The plasma levels of tissue-type plasminogen activator antigen (t-PA), prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin complex (TAT) were measured by ELISA. Plasminogen activator inhibitor type I (PAI-1) was measured by an immunoactivity assay and fibrinogen by von Clauss method. GH levels were measured by IFMA and IGF-I by RIA. GHD patients had higher PAI-1 (12.7+/-16.7 vs 4.8+/-5.3 U/ml, p<0.01), fibrinogen (363+/-104 vs 291+/-71 mg/dL, p< 0.05) and TAT levels (6.8+/-9 vs 3.6+/-2.8 ng/ml, p<0.05) than controls. Taking the 95th pecentile of the normal distribution in the control group as the cut-off point for normal plasma levels of the haemostatic variables, high PAI levels were found in 25% of patients with GHD (P<0.01), while high fibrinogen and TAT levels were observed in 21% (P<0.05). The alterations were mostly present in patients with adult-onset GHD, with the exception of hyperfibrinogenaemia which was equally present in adult- and childhood-onset patients. Acromegalic patients had higher mean fibrinogen levels than controls (398+/-111 vs 291+/-71 mg/dL, p< 0.05), 40% having hyperfibrinogenaemia (P<0.01, vs controls). They also had t-PA levels lower than controls and GHD. No correlations between hormonal and haemostatic variables were found. Body mass index and waist to hip ratio correlated positively with PAI-1 levels in GHD patients only. In conclusion, this study shows that several abnormalities of coagulation variables (increased PAI-1. fibrinogen and TAT levels) are present in patients with GHD, while only hyperfibrinogenaemia is found in patients with acromegaly. These changes do not appear to be directly related to IGF-I levels or to the degree of GH deficiency/excess. However, these abnormalities may be an additional trigger for the development of coronary heart disease and thromboembolic complications mostly in patients with GHD.