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Long-term management of acromegaly with sandostatin.

The present report illustrates the effectiveness of a long-acting somatostatin analog, SMS 201-995 (Sandostatin), in the chronic treatment of acromegaly. Daily doses of 50-300 micrograms were administered subcutaneously to 37 patients. Gradual dose increments induced a progressive GH decrease accompanied by a parallel reduction in plasma somatomedin C concentrations. There was a concomitant amelioration of clinical signs and symptoms throughout the investigational period. No escape phenomenon or tachyphylaxis was observed. It is concluded that chronic therapy with SMS 201-995 represents a promising medical alternative for the treatment of active acromegaly.

Acromegaly↗

Long-term treatment of acromegaly with octreotide (Sandostatin).

Sixteen patients with acromegaly have been treated with octreotide [100 micrograms twice daily to 200 micrograms 3 times daily according to growth hormone (GH) response] for between 3 and 44 months. The mean serum GH concentrations fell from 39.3 mU/l before treatment to 10.5 mU/l on day 1 of treatment and, with continued treatment (and higher doses in 8 of 16 patients), to 7.9 mU/l. In 2 patients there was no GH suppression. GH suppression after the first administration of octreotide appeared to predict long-term response. Pre-treatment serum insulin-like growth factor 1 levels were elevated in 11 of 12 patients investigated, but were normalized on continued octreotide therapy in 10 of 12. Octreotide suppressed prolactin secretion in all 6 hyperprolactinaemic patients. Steatorrhoea occurred in 15 of 16 patients at initiation of treatment, but resolved in all within 7 days. Two patients developed gallstones. In summary, octreotide is a safe and effective treatment for acromegaly, producing clinical and biochemical improvement in up to 90% of patients. Octreotide is a valuable adjunctive treatment where surgery has failed and also in those with contra-indications to surgery.

Acromegaly↗

Recurrence following transsphenoidal surgery for acromegaly.

The long-term results of transsphenoidal adenomectomy and the incidence of possible recurrences were studied in 61 patients who had normal basal serum growth hormone (GH) levels 1 week after surgery. The patients were followed up for an average of 6.0 years (range: 1.5-14.0 years) by repeated measurements of GH, oral glucose tolerance testing (OGTT) and at the last follow-up visit also by assaying somatomedin C levels. In 4 of the patients, the basal GH levels had increased to values above 5 ng/ml. In 43 patients, a normal suppression of GH during an oral glucose load was observed shortly after surgery. In only 2 of these cases did a transiently inadequate suppression develop during the follow-up period, although clinical acromegaly did not recur and the somatomedin C levels remained normal. It is concluded that recurrence of active acromegaly is unlikely to occur in patients who achieve a normal glucose-induced suppression of GH levels shortly after adenomectomy. As such, an OGTT provides better prognostic information than basal human GH level measurements and may give a clearer and earlier indication of surgical success.

Acromegaly↗

Effects of pirenzepine, bromocriptine and their association on basal and GHRH- and TRH-induced GH secretion in acromegaly.

In order to ascertain if pirenzepine (Pz), an antimuscarinic drug, could inhibit GH secretion in acromegaly, 8 patients were submitted to 3 successive treatment courses of 9 days each: Pz, bromocriptine (BRC) and Pz plus BRC. No change in basal levels of GH after Pz administration was seen, but its reduction (p less than 0.05) by BRC was observed. Pz plus BRC did not improve this response. None of these drugs abolished the paradoxical GH response to TRH. In 7 normal controls, Pz suppressed the GH responsiveness to GHRH (p less than 0.001), but not in acromegalic patients. BRC, instead, blunted this response. In conclusion, cholinergic control of GH secretion is altered in acromegaly. Pz, either when administered alone or associated with BRC, is not useful for the treatment of this disease.

Acromegaly↗

Resistance to somatostatin (SRIH) analog therapy in acromegaly. Re-evaluation of the correlation between the SRIH receptor status of the pituitary tumor and the in vivo inhibition of GH secretion in response to SRIH analog.

The development of a long-acting somatostatin (SRIH) analog (octreotide, Sandoz) has been a major breakthrough in the treatment of acromegaly. However, in 20-30% of the patients, growth hormone (GH) plasma levels remain elevated (> 10 micrograms/l) despite treatment with octreotide. This raised the concept of resistance to SRIH analog therapy in acromegaly. Indeed, in vivo response to SRIH analogs varies greatly among acromegalic patients. According to the reviews in the literature and our own autoradiographic data, no direct correlation can be established between the GH response to octreotide and the number or affinity of the SRIH receptors located on the tumor. In our series a greater density of SRIH receptors is present on tumors from patients very sensitive to the SRIH agonist. A subset of patients resistant to octreotide could result from a very low density of SRIH receptor although this type of GH-secreting tumor constitutes certainly a rare case. A subset of GH-secreting pituitary tumors can be characterized by a mutation on the alpha subunit of the guanine nucleotide-dependent protein coupled to the stimulation of adenylate cyclase (G alpha s). This mutation results in a high basal adenylate cyclase activity and a low GHRH-stimulated activity. However, when the adenomas are separated according to their basal adenylate cyclase activity, SRIH is able to decrease cAMP levels in both types of tumor. In addition, in our series no direct correlation is observed between the SRIH inhibition of adenylate cyclase and the amount of SRIH-binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗

Measurement of inorganic pyrophosphate in biological fluids. Elevated levels in some patients with osteoarthritis, pseudogout, acromegaly, and uremia.

A rapid and relatively simple method for measurement of inorganic pyrophosphate (PPi) in biological samples has been described. The mean +/-SEM of plasma samples from 94 normal subjects was 1.8+/-0.06 muM, giving a normal range (99% confidence limits) of 0.16 - 3.40 mumol/liter. Analysis of 17 plasma samples in duplicate showed a standard deviation of 0.18, giving a 99% probability that a single determination of plasma PPi would be +/-0.68 muM of the true value. The mean PPi levels in plasma from subjects with osteoarthritis, pseudogout, acromegaly, and uremia were significantly greater than the normal mean (P < 0.01). Samples from rheumatoid arthritis showed PPi levels distributed about a mean identical to the normal mean. Plasma inorganic orthophosphate levels correlated positively with PPi levels in samples from normal subjects and in samples from patients with osteoarthritis, pseudogout, and uremia, but not with acromegaly. This correlation was statistically significant only in the normal samples and in those from patients with osteoarthritis.

Acromegaly↗

Acromegaly: a rare manifestation of bronchial carcinoid.

Bronchial carcinoids usually present with pulmonary symptoms. Neurohumoral manifestations in the form of acromegaly and Cushing's syndrome are rarely encountered. We report a case of bronchial carcinoid with features of acromegaly due to ectopic production of growth hormone-releasing hormone. Surgical resection of the lung lesion resulted in regression of acromegalic features, normalization of growth hormone secretory dynamics, and remarkable diminution of pituitary size seen on magnetic resonance imaging.

Acromegaly↗

Valve repair with maze procedure in acromegaly.

Acromegaly is characterized by a hypersecretion of growth hormone and is frequently associated with valvular abnormality and arrhythmia. The increased morbidity and mortality is primarily caused by stroke and cardiovascular disease. Therefore, valve reconstruction and sinus rhythm recovery will be particularly beneficial. We report herein the successful surgical treatment of two patients with combined valvular insufficiency and chronic atrial fibrillation in the setting of acromegaly.

Acromegaly↗

A case and review of acromegaly-induced cardiomyopathy and the relationship between growth hormone and heart failure: cause or cure or neither or both?

Growth hormone plays an integral role in the development and maintenance of structure and function of the heart. Specific involvement of the heart in acromegaly is termed acromegalic cardiomyopathy, manifested as concentric left ventricular hypertrophy and diastolic dys-function. Left untreated, it ultimately progresses to systolic heart failure. Heart failure from acromegalic cardiomyopathy is one of the most common causes of death in acromegaly. Current treatment options include different approaches to lower elevated growth hormone levels with improvement in symptoms, exercise tolerance, and echocardiographic improvement in regression of left ventricular hypertrophy and indices of diastolic dysfunction. On the other hand, growth hormone is essential for cardiac growth and function and exerts beneficial and protective effects on the cardiovascular system. Its potential role as adjunctive therapy in the treatment of heart failure as derived from experimental studies and clinical trials is discussed.

Acromegaly↗

Relief of sleep apnoea after treatment of acromegaly: report of three cases and review of the literature.

Sleep apnoea syndrome (SAS) is common in acromegalic patients. Occasionally, the relief of apnoeas after treatment of the acromegaly has been documented. We report the cases of three patients with acromegaly and severe obstructive sleep apnoea, who demonstrated a manifest improvement (respiratory disturbance index (RDI) <20) after treatment with octreotide, indicating that this drug may be effective in this disturbance. In one case, SAS disappeared although the growth hormone level was not fully normalized. This raises the intriguing hypothesis that octreotide has an effect on respiratory control or on the upper airway, that is not directly related to its action on production of growth hormone.

Acromegaly↗

Growth hormone receptor antagonists: discovery, development, and use in patients with acromegaly.

An understanding of the events that occur during GH receptor (GHR) signaling has facilitated the development of a GHR antagonist (pegvisomant) for use in humans. This molecule has been designed to compete with native GH for the GHR and to prevent its proper or functional dimerization-a process that is critical for GH signal transduction and IGF-I synthesis and secretion. Clinical trials in patients with acromegaly show GHR blockade to be an exciting new mode of therapy for this condition, and pegvisomant may have a therapeutic role in diseases, such as diabetes and malignancy, in which abnormalities of the GH/IGF-I axis have been observed. This review charts the discovery and development of GHR antagonists and details the experience gained in patients with acromegaly.

Acromegaly↗

Primary medical therapy for acromegaly: an open, prospective, multicenter study of the effects of subcutaneous and intramuscular slow-release octreotide on growth hormone, insulin-like growth factor-I, and tumor size.

Conventional surgery and radiotherapy for acromegaly have limitations. There are few data on the use of the somatostatin analog octreotide (Oct) as primary medical therapy. An open prospective study of 27 patients with newly diagnosed acromegaly was conducted in nine endocrine centers in the United Kingdom. Twenty patients had macroadenomas, and 7 had microadenomas. For the first 24 wk (phase 1), patients received sc Oct in an initial dose of 100 microg, 3 times daily, increased to 200 micro g three times daily after 4 wk in the 13 patients whose mean serum GH remained greater than 5 mU/liter (2 microg/liter). Five-point GH profiles were performed at 0, 4, 12, and 24 wk, and high resolution pituitary imaging using a standard protocol was performed at 0, 12, and 24 wk (magnetic resonance imaging in 25 patients and computed tomography in 2). Tumor dimensions and volumes were calculated by a central, reporting neuroradiologist, and the results were audited by a second, independent neuroradiologist. After 24 wk, 15 patients proceeded to phase 2 of the study with a direct switch to monthly injections of the depot formulation of Oct, Sandostatin long-acting release (Oct-LAR). Further GH profiles were performed at 36 and 48 wk, and pituitary imaging was performed at 48 wk. The median pretreatment serum GH concentration was 30.7 mU/liter (range, 6.7-141.4). During sc Oct, serum GH fell to less than 5 mU/liter in 9 patients (38%), and IGF-I fell to normal in 8 patients (33%). All 27 tumors shrank during sc Oct; for microadenomas the median tumor volume reduction was 49% (range, 12-73), and for macroadenomas it was 43% (range, 6-92). After 24 wk of Oct-LAR (end of phase 2), the GH level was less than 5 mU/liter in 11 of 14 patients (79%), and IGF-I was normal in 8 of 15 patients (53%). In the 15 patients given Oct-LAR (10 macroadenomas), wk 48 scans showed a further overall median tumor volume reduction of 24%. At the end of the study 79% of patients had mean serum GH levels below 5 mU/liter, 53% had normal IGF-I levels, and 73% showed greater than 30% tumor shrinkage. Twenty-nine percent of patients achieved all 3 targets, but no patient with pretreatment GH levels above 50 mU/liter did so at any stage of the study. Primary medical therapy with Oct offers the prospect of normalization of GH/IGF-I levels together with substantial tumor shrinkage in a significant subset of acromegalic patients. This is most likely to occur in patients with pretreatment GH levels less than 50 mU/liter (20 microg/liter).

Acromegaly↗

Short-term suppression of GH and IGF-I levels improves gonadal function and sperm parameters in men with acromegaly.

Experimental data support a role for GH and IGF-I in the reproductive process in humans, but the effect of chronic GH excess on gonadal and reproductive function in men has been never investigated. To understand the effects of short-term GH and IGF-I suppression on the gonadal axis and seminal fluid characteristics in men with acromegaly, we evaluated 35 patients (age 27-59 yr) with active disease and 35 age-matched healthy controls. Gonadal hormones and seminal fluid analysis were evaluated before and 6 months after surgery or lanreotide (LAN) (60 mg/month). At study entry, FSH, testosterone (T), and dihydrotestosterone (DHT) (P < 0.0001) levels, seminal volume, sperm count, total motility and forward progression, normal morphology, and vitality were significantly lower in patients with acromegaly than in controls. After 6 months, 22 patients achieved disease control after surgery (n = 11) or LAN (n = 11), whereas 13 had uncontrolled disease. Serum T and DHT levels and sperm number significantly increased in all groups. FSH and LH levels and total motility increased only in patients achieving disease control. Posttreatment IGF-I levels significantly correlated with total motility (r = -0.45; P = 0.006). In conclusion, short-term GH and IGF-I suppression after surgery or LAN significantly increased T and DHT levels and improved sperm number and motility in acromegalic men.

Acromegaly↗

Gamma-knife radiosurgery in acromegaly: a 4-year follow-up study.

Stereotactic radiosurgery by gamma-knife (GK) is an attractive therapeutic option after failure of microsurgical removal in patients with pituitary adenoma. In these tumors or remnants of them, it aims to obtain the arrest of cell proliferation and hormone hypersecretion using a single precise high dose of ionizing radiation, sparing surrounding structures. The long-term efficacy and toxicity of GK in acromegaly are only partially known. Thirty acromegalic patients (14 women and 16 men) entered a prospective study of GK treatment. Most were surgical failures, whereas in 3 GK was the primary treatment. Imaging of the adenoma and target coordinates identification were obtained by high resolution magnetic resonance imaging. All patients were treated with multiple isocenters (mean, 8; range, 3-11). The 50% isodose was used in 27 patients (90%). The mean margin dose was 20 Gy (range, 15-35), and the dose to the visual pathways was always less than 8 Gy. After a median follow-up of 46 months (range, 9-96), IGF-I fell from 805 micro g/liter (median; interquartile range, 640-994) to 460 micro g/liter (interquartile range, 217-654; P = 0.0002), and normal age-matched IGF-I levels were reached in 7 patients (23%). Mean GH levels decreased from 10 micro g/liter (interquartile range, 6.4-15) to 2.9 micro g/liter (interquartile range, 2-5.3; P < 0.0001), reaching levels below 2.5 micro g/liter in 11 (37%). The rate of persistently pathological hormonal levels was still 70% at 5 yr by Kaplan-Meier analysis. The median volume was 1.43 ml (range, 0.20-3.7). Tumor shrinkage (at least 25% of basal volume) occurred after 24 months (range, 12-36) in 11 of 19 patients (58% of assessable patients). The rate of shrinkage was 79% at 4 yr. In no case was further growth observed. Only 1 patient complained of side-effects (severe headache and nausea immediately after the procedure, with full recovery in a few days with steroid therapy). Anterior pituitary failures were observed in 2 patients, who already had partial hypopituitarism, after 2 and 6 yr, respectively. No patient developed visual deficits. GK is a valid adjunctive tool in the management of acromegaly that controls GH/IGF-I hypersecretion and tumor growth, with shrinkage of adenoma and no recurrence of the disease in the considered observation period and with low acute and chronic toxicity.

Acromegaly↗

Transsphenoidal surgery for acromegaly in wales: results based on stringent criteria of remission.

We retrospectively analyzed 90 patients who underwent transsphenoidal surgery (performed by three surgeons) in our center as initial therapy for acromegaly. We used a combination of modern, evidence-based remission criteria including mean day curve GH less than 2.5 micro g/liter (5 mU/liter), a nadir GH less than 1.0 micro g/liter (2 mU/liter) after an oral glucose tolerance test, and normal age-related IGF-I levels (where available). Fifty-seven of 90 (63%) patients remained in remission after surgery. Seventy-nine percent of patients with microadenomas but only 56% of patients with macroadenomas achieved remission (P < 0.001). Eighty-six percent of patients with preoperative GH levels below 10 micro g/liter (day profile or after oral glucose tolerance test) went into remission, compared with 51% of patients with GH levels above 25 micro g/liter at diagnosis (P < 0.002). The remission rate was also related to the period of surgery that was significantly higher in 1998-2001 (76%; P < 0.05) compared with 1990-1997 (54%) and 1980-1989 (63%). There were no recurrences or perioperative deaths. Meningitis occurred in 3% of patients, cerebrospinal fluid rhinorrhea in 7%, and permanent diabetes insipidus in 15%. The proportion of patients who developed new anterior pituitary hormone deficiencies and panhypopituitarism was significantly less in the period 1998-2001 (P < 0.001) when compared with the periods from 1990-1997 and 1980-1989. Transsphenoidal surgery is a safe and effective treatment for acromegaly, and our results compare favorably with those from published series. The presence of an intrasellar lesion and low preoperative GH levels is a good predictor of remission in the long term, but historically in our center this can only be achieved in a significant proportion of patients at the expense of some degree of hypopituitarism. However, surgical outcome in our center, including a reduced frequency of hypopituitarism, has improved significantly over time, coincident with the arrival of a dedicated pituitary neurosurgeon and the use of selective adenomectomy as the preferred surgical approach wherever possible.

Acromegaly↗

Decreased quality of life in patients with acromegaly despite long-term cure of growth hormone excess.

The long-term impact of acromegaly on subjective well-being after treatment of GH excess is unclear. Therefore, we evaluated quality of life by validated questionnaires in a cross-sectional study of 118 successfully treated acromegalic patients. The initial treatment was transsphenoidal surgery in most patients (92%), if necessary followed by radiotherapy or octreotide. All patients were in remission at the time of assessment (GH, <1.9 mug/liter; normal IGF-I for age). General perceived well-being was reduced compared with controls for all subscales (P < 0.001) as measured by the Nottingham Health Profile and the Short Form-36. Acromegalic patients also had lower scores on fatigue (Multidimensional Fatigue Index) and anxiety and depression (Hospital Anxiety and Depression Scale). Radiotherapy was associated with decreased quality of life in all subscales except for the Hospital Anxiety and Depression Scale, and worsened quality of life significantly, according to the fatigue scores. Somatostatin analog treatment was not associated with improved quality of life. Independent predictors of quality of life were age (physical subscales and Nottingham Health Profile), disease duration (social isolation and personal relations), and radiotherapy (physical and fatigue subscales). In conclusion, patients cured after treatment for acromegaly have a persistently decreased quality of life despite long-term biochemical cure of GH excess. Radiotherapy especially is associated with a reduced quality of life.

Acromegaly↗

Alternate-day administration of pegvisomant maintains normal serum insulin-like growth factor-I levels in patients with acromegaly.

IGF-I levels normalize in the majority of patients with acromegaly treated with the GH receptor antagonist pegvisomant. To date, the efficacy of pegvisomant has been demonstrated with daily administration of doses ranging from 10 to 40 mg. However, given the known long half-life of the drug in circulation, we hypothesized that dosing less frequently than daily would still maintain the drug's efficacy. We studied 10 patients with active acromegaly treated with pegvisomant. This therapy was begun at 10 mg daily but then titrated up in dose or down to alternate-day dosing to try to maintain serum IGF-I levels in the upper half of the patients' age-adjusted normal range. We found that in five of 10 patients, serum IGF-I levels remained normal on less frequent than daily pegvisomant. Signs and symptoms of the disease and a disease-related morbidity, insulin resistance, remained improved in these patients. We demonstrate for the first time the continued efficacy of alternate-day administration of pegvisomant.

Acromegaly↗

A critical analysis of pituitary tumor shrinkage during primary medical therapy in acromegaly.

CONTEXT: Somatostatin analogs have been successfully used to treat patients with GH-secreting pituitary adenomas because they are safe, effective, and usually well tolerated. The results of studies evaluating acromegaly treatment with the somatostatin receptor ligands (SRLs), octreotide and lanreotide, have supported the use of these agents for primary medical therapy before or as an alternative to traditional interventions of surgery and radiotherapy in selected cases. EVIDENCE ACQUISITION: We therefore undertook a systematic literature overview to characterize the results of studies involving primary therapy with somatostatin analogs and their effects on pituitary tumor size. Because most studies in which pituitary tumor shrinkage has been assessed involve uncontrolled, open-label, prospective trials or retrospective case series, the lack of a control arm does not permit pooling of data in a metaanalytic fashion to determine tumor size reduction. Therefore, this systematic review was designed to document and stratify data by study design, summarize therapeutic regimens and patient characteristics, assess the percentage of patients showing changes in tumor size, and calculate the weighted average effect on size reduction. EVIDENCE SYNTHESIS: Overall, for patients who experience significant shrinkage, an approximately 50% decrease in pituitary mass is achieved when a somatostatin analog is used exclusively or before surgery or radiotherapy. Fourteen studies (n = 424) provided a definition of significant tumor shrinkage, and the results showed that 36.6% (weighted mean percentage) of patients receiving primary SRL therapy for acromegaly experienced a significant reduction in tumor size. The weighted mean percent reduction in tumor size was 19.4% for those studies in which all patients received SRLs and change in tumor size was reported for all patients. CONCLUSIONS: Clinical implications are discussed for patients in whom tumor size control with SRLs is an important objective, typically those who have failed surgery or are being treated with primary medical therapy with large tumors.

Acromegaly↗