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Effect of octreotide on 24-h blood pressure profile in acromegaly.

The aim of the study was to investigate the effect of octreotide, a somatostatin analog drug potentially able to inhibit growth hormone (GH), on the circadian blood pressure profile in a group of patients with acromegaly. Ten patients with GH-secreting pituitary adenoma were studied before and 6 months after treatment with subcutaneous octreotide 0.2 to 0.6 mg/day. Twenty-four hour blood pressure and heart rate were measured every 15 min at daytime (07:00 to 22:59) and every 30 min at nighttime (23:00 to 06:59) using a TM-2420 recorder. No correlation was found between GH levels and 24-h blood pressure in baseline conditions. Untreated patients had a significant nocturnal decrease of both systolic and diastolic blood pressure (P < .01), and all showed a circadian systolic or diastolic blood pressure rhythm. During octreotide treatment, 24 h as well as nighttime systolic and diastolic blood pressures significantly increased (P < .05), whereas daytime systolic and diastolic blood pressures did not change. Treated patients did not have a nocturnal decline in both systolic and diastolic blood pressures (P = NS), and eight lost their systolic or diastolic blood pressure rhythm. In conclusion, blood pressure circadian rhythm seems to be maintained in acromegaly. Octreotide treatment is associated with an increase of 24-h and nighttime blood pressure, and with loss of circadian blood pressure rhythm. Splanchnic vasoconstriction by this drug, shifting blood to peripheral vessels, may explain this phenomenon.

Acromegaly↗

Acromegaly identified in a patient with a complaint of malocclusion.

Acromegaly in a female patient was first diagnosed after a dental examination at which time the patient complained of the inability to incise properly. An elevated serum growth hormone level and enlarged sella turcica confirmed the diagnosis of acromegaly. Based on examination of her plaster study models, it was apparent the patient had been developing a change in her dentition for years.

Acromegaly↗

Follow-up of treated acromegaly: similarities and differences in assessing the response to different primary treatment modalities.

The decreased survival rate previously reported in patients with acromegaly can be normalized by successful surgical and adjunctive therapy. After surgical treatment, however, abnormalities of pulsatile growth hormone (GH) secretion may persist in spite of normal insulin-like growth factor I (IGF-I) levels, and there is a significant relapse rate. Radiotherapy is effective in lowering GH levels but relatively ineffective in normalizing IGF-I levels. There are very few data on long-term outcome after medical treatment of acromegaly, although current studies of patients receiving primary medical therapy will produce further information. IGF-I level may become an increasingly important biochemical end point. The goal of therapy is to achieve a biochemical value that reverses both the morbidity and increased mortality rate without resulting in hypopituitarism.

Acromegaly↗

Pegvisomant: a growth hormone receptor antagonist for the treatment of acromegaly.

Growth hormone receptor (GHR) dimerization is a prerequisite to the generation of growth hormone (GH) action. Pegvisomant is a GHR antagonist that has been designed to bind to the GHR at the cell surface and hence block this process. Initial studies suggest that pegvisomant is a highly effective antagonist of GH action in patients with acromegaly. The blockade of GH action, rather than the inhibition of pituitary GH secretion, represents a novel concept in the medical management of acromegaly. In this review, the design, efficacy, challenges and future role of pegvisomant are discussed.

Acromegaly↗

The sweating apparatus in growth hormone deficiency, following treatment with r-hGH and in acromegaly.

Adult growth hormone deficient patients are known to exhibit reduced sweating and their ability to thermoregulate is diminished. Treatment of these patients with recombinant human growth hormone (r-hGH) is claimed to reverse these abnormalities. We have investigated this claim, as well as the mechanism underlying these altered sweating responses in GH-deficient patients as part of a placebo-controlled study on the effects of 6-12 months r-hGH therapy. Skin biopsies were obtained from these subjects and changes in morphology and innervation parameters for the eccrine sweat glands were examined. These included histochemistry for acetylcholinesterase (AChE) and immunohistochemistry for the neuropeptide vasoactive intestinal polypeptide (VIP) and for PGP9.5, a general neuronal marker. Sweat gland acinar size and periacinar innervation were measured by computerised image analysis. The patients underwent pilocarpine iontophoresis sweat rate tests and their serum insulin-like growth factor 1 (IGF-1) levels were assessed. Since active acromegaly involves excess GH secretion and hyperhidrosis, skin biopsies and sweat tests were also carried out on a group of these patients, as well as on control subjects. We have demonstrated a sweating defect in adult GH-deficiency which is accompanied by a reduction in AChE and VIP levels in the nerve supply to sweat glands. Following r-hGH therapy, an increase in AChE and VIP staining is seen in the sudomotor nerves accompanied by restoration of sweat rates and serum IGF-1 levels. Hence, normalization of sweat gland function includes recovery of sudomotor synapse constituents. A trophic effect of GH on sweat gland epithelium and/or on the associated nerves is proposed, supported by the observation that in acromegaly the size of sweat gland acini and the density of innervation to the sweat glands was greater than in controls.

Acetylcholinesterase↗

Acromegaly and the temporal bone.

Acromegaly is a chronic disease of middle life resulting from excessive secretion of growth hormones by the acidophil cells of the anterior pituitary. The typical clinical features include enlargement of the skull, thorax, hands and feet. Recently, three patients with acromegaly have been operated upon for active otologic disease. In spite of massive mastoid cortex bone, the structures of the otic capsule were found to be of normal dimensions and in the usual relationships.

Acromegaly↗

Hearing in acromegaly.

Fifty-six individuals with acromegaly referred for pituitary surgery were studied to determine any relationship between acromegaly and sensorineural or conductive hearing loss. Compared to a matched population control sample, no significant difference between the acromegalics and controls has been found, either for air conduction or for bone conduction. The differences between these findings and those published previously are discussed, and reasons proposed to explain the discrepancies.

Acromegaly↗

Molecular pathogenesis of acromegaly.

Acromegaly is generally caused by growth hormone (GH) hypersecretion from a benign, monoclonal pituitary adenoma. As in other neoplastic conditions, pituitary tumor formation and dysregulated hormone secretion are most likely the ultimate result of a series of genetic alterations. A number of molecular and biochemical defects have been associated with pituitary tumorigenesis. Molecular events such as tumor suppressor gene inactivation and oncogene activation involved in pituitary tumor progression are examined. The role of hypothalamic regulatory hormones and hereditary syndromes involving acromegaly are also discussed.

Acromegaly↗

Acromegaly with normal growth hormone levels: response to Sandostatin-LAR treatment.

We report a case of acromegaly with relatively low GH secretion in a patient with GH-secreting pituitary macroadenoma. The 44-year-old male patient presented with left temporal hemianopsia and characteristic acromegalic face, but had relatively low baseline and post-glucose GH levels. IGF-1 and IGFBP-1 were elevated. Transsphenoidal surgery did not achieve clinical or biochemiacl remission, and the patient still had elevated IGF-1 levels with low GH. Histological examination of the resected tumor revealed a pituitary adenoma stained weakly for GH. The patient was treated then with monthly injections of Sandostatin-LAR, with clinical improvement and suppression of IGF-I to the normal range. This is a rare case of acromegaly without elevated GH levels, and good response to treatment with somatostatin analog, as expected in classical GH-secreting pituitary adenomas.

Acromegaly↗

Epidemiology of acromegaly.

Acromegaly is a consequence of chronic growth hormone (GH) excess, due in the majority of cases to a GH-secreting pituitary adenoma, and occurring with a population prevalence of 60 per million and an incidence of 3-4 per million per year. Males and females appear to be equally affected with an average age of presentation of 44 years. Younger patients may have more aggressive tumours and higher GH concentrations. There is co-existent hyperprolactinaemia in about one third of cases, and a variable proportion of [figure: see text] tumours appear to have activating mutations of the gsp gene or other genetic abnormalities. Acute complications such as carpal tunnel syndrome, sweating and obstructive sleep apnoea are usually readily reversible with treatment of the condition, but chronic complications such as hypertension, diabetes and heart disease are less readily corrected and post-treatment GH levels of < 2.5 ug/L (5 mU/L) are needed to achieve the prevalence found in the general community. Such 'curative' levels of GH are achieved in only about 50% of patients with current therapies, and as a result there is an ongoing excess of patients with chronic complications of acromegaly leading to increased morbidity and mortality from the disorder, with observed-to-expected mortality ratios ranging from 1.6-3.3 and only approaching unity in those with growth hormone levels < 2.5 ug/L following treatment. Prognostic factors include in some studies the presence of diabetes and [table: see text] hypertension prior to diagnosis as well as measures of exposure to excessive growth hormone derived from the product of preoperative serum GH and the time from first symptoms to treatment. Overall, however, the most important prognostic variable appears to be the serum GH concentration achieved by treatment, with an increasing consensus that this needs to be < 2.5 ug/L (5 mU/L) to achieve cure of the condition.

Acromegaly↗

Self image and quality of life in acromegaly.

Chronic effects of excessive GH secretion are not only disabling but also disfiguring. Most acromegalic patients present with 4-10 years history of changes in features, bony overgrowth, soft tissue swelling, skin changes, diabetes mellitus, hypertension and other cardiovascular symptoms. In addition to sign and symptoms of GH excess the patients demonstrate a loss initiative and spontaneity, mood swings, an impairments in self esteem, body image distortion, disruption in interpersonal relations and social withdrawal anxiety. Little research is available on the psychological features of acromegaly, despite their importance in this chronic and debilitating condition. Extremely little, however has appeared in the medical and psychological literature about mental and emotional disfunction in patients with acromegaly.

Acromegaly↗

Drug insight: Primary medical therapy of acromegaly.

Acromegaly is an insidious disease that, in most cases, is a result of a pituitary adenoma that hypersecretes growth hormone (GH). The goals of therapy are to control excess GH secretion and limit, if not reverse, the long-term medical consequences and risk of premature mortality associated with acromegaly. Surgery is currently the preferred primary therapeutic option because it can lead to rapid reductions in GH levels and prevent mass effects from local tumor growth. Medical therapy is used most often in an adjuvant, secondary role for patients in whom surgery has been unsuccessful. Radiation therapy is most commonly recommended in the setting of failed surgery and lack of adequate control with medical therapy. A role of primary medical therapy for patients de novo has been proposed, particularly with regard to somatostatin analogues. These analogues may control GH levels and reduce tumor volume in up to 50% of subjects, suggesting that they may be efficacious in this context. The use of somatostatin analogues to improve surgical outcome has also been proposed, but there is a lack of randomized trials available to address this issue. Primary medical therapy is well tolerated and further studies are necessary to identify patients who should be targeted for such therapy.

Acromegaly↗

Acromegaly diagnosed in a young woman presenting with headache and arthritis.

BACKGROUND: A 38-year-old woman presented with severe headaches to her primary-care physician. The patient had been diagnosed with rheumatoid arthritis and had begun having headache 4 years previously. An MRI scan revealed an 11-12 mm pituitary tumor. Her physical examination was unremarkable for the classic acral or facial changes characteristic of acromegaly, and she was referred for neuroendocrine consultation for a presumed nonfunctioning adenoma. INVESTIGATIONS: MRI of the pituitary, and laboratory investigations that included measurement of serum insulin-like growth factor 1 (IGF1) and prolactin levels. DIAGNOSIS: In view of the elevated level of IGF1 and presence of a pituitary adenoma, the patient was diagnosed with acromegaly caused by a pituitary adenoma that secretes growth hormone. MANAGEMENT: The patient underwent trans-sphenoidal surgery, which resulted in resolution of joint pain and headache, eradication of the tumor mass, normal IGF1 levels, and appropriate suppression of growth hormone (confirmed by oral glucose tolerance test postoperatively).

Acromegaly↗

Retrospective analysis of long-term surgical results in acromegaly: preoperative and postoperative factors predicting outcome.

OBJECTIVE: Sixty-one of 83 patients with acromegaly treated between 1969 and 1993 were analysed retrospectively to clarify which early postoperative factors were significant predictors of a successful long-term outcome and which preoperative factors significantly influenced the early postoperative results. PATIENTS: Of the 61 patients, 30 were operated on before 1987 and 31 afterwards. A successful long-term surgical outcome was defined as a long-term mean basal GH level < 6 mU/l (comparable to < 3 micrograms/l), a normal IGF-I level, and normal GH dynamics. RESULTS: Overall, 59% of patients (37% before 1987 and 81% after) had an early postoperative mean basal GH level < 6 mU/l, and 56% (29% before 1987 and 77% after) met all three of the specified criteria for a successful long-term surgical outcome. Statistical analysis confirmed that GH dynamics and postoperative mean basal GH level < 6 mU/l were significant predictors of the long-term surgical outcome, whereas the postoperative IGF-I level alone was not. On the other hand, abnormal preoperative GH dynamics were normalized in all patients with a postoperative mean basal level < 6 mU/l. In addition, there were no patients showing an unsuccessful long-term outcome in those associated with both the early postoperative mean basal GH level < 6 mU/l and normalization of the IGF-I level. Therefore, measurement of the early postoperative mean basal GH level and the IGF-I level may be an economical and simple guide to predict the long-term surgical outcome. Moreover, multivariate analysis indicated that cavernous sinus invasion was an independent significant factor influencing the early postoperative outcome. CONCLUSIONS: Successful long-term surgical outcome may be predicted if early postoperative mean basal GH level is reduced to < 6 mU/l (< 3 micrograms/l) and IGF-I level becomes normal. This study also confirms that early diagnosis and treatment by an experienced endocrinologist and neurosurgeon can improve the operative results in patients with acromegaly.

Acromegaly↗

Increased prevalence of colonic polyps and altered lymphocyte subset pattern in the colonic lamina propria in acromegaly.

OBJECTIVE: The balance of evidence suggests that acromegaly is a risk factor for colonic neoplasia. We have evaluated the prevalence of colonic polyps in acromegalics from Southern Italy and characterized the lymphocyte subsets in the colonic lamina propria in order to analyze differences in the colonic immunological environment. DESIGN: All the patients and controls were submitted to pancolonoscopy. Ten per-endoscopic biopsies of the intestinal mucosa surrounding polyps were carried out to evaluate lymphocyte subsets. PATIENTS: Fifty acromegalics and 318 sex- and age-matched controls entered this study. Colonic lamina propria lymphocyte subsets were studied in 34 patients and 34 controls. RESULTS: Colonic polyps were resected in 23 acromegalics (46%) and 42 controls (13.2%; P < 0.0001); hyperplastic polyps were found in 24% and 6.3%, adenomatous polyps in 22 and 6.9%, (P < 0.01), adenocarcinoma in 2 and 1.2% while synchronous polyps occurred in 18% and 2.5% (P < 0.01), respectively. The number of polyps was significantly correlated with age both in acromegalics (r = 0.422, P < 0.005) and in controls (r = 0.865, P < 0.001). However, polyp prevalence was greater in patients aged below 40 yrs (r.r = 1.9) and in patients with two or more skin tags (r.r = 1.2). A significant decrease of CD20, CD19, CD16, gamma/delta, CD4@leu8- and increase of CD3 and CD4+/leu8+ was found in the lamina propria lymphocyte subsets. CONCLUSIONS: The results of this study confirm that acromegalics are at increased risk of colonic polyps compared to the healthy population. The increased prevalence of premalignant polyps, namely the adenomatous type, suggests that acromegalics should undergo a careful screening and follow-up by pancolonoscopy. An impairment of mucosal immune surveillance seems to exist in acromegaly although a causal effect in the polyp formation cannot be ruled out.

Acromegaly↗

Circadian variation in serum free and total insulin-like growth factor (IGF)-I and IGF-II in untreated and treated acromegaly and growth hormone deficiency.

OBJECTIVE: It is generally accepted that there is no clinically significant circadian variation in total insulin-like growth factor (IGF)-I or total IGF-II in healthy subjects. In contrast there is a significant nocturnal decrease in free IGF-I in healthy subjects, corresponding to the nocturnal increase in IGF binding protein-1. In this study we have investigated the circadian variation in circulating free IGF-I and IGF-II in patients with acromegaly and patients with adult onset growth hormone deficiency. PATIENTS: Seven acromegalic patients were studied with and without treatment with a slow-release formulation of octreotide. Seven GH-deficient patients were studied without GH replacement. In addition 5 of the GH-deficient patients were studied during GH replacement. DESIGN: Serum samples were obtained every hour for 24 h. Free IGF-I and IGF-II were measured every 2nd hour. Total IGF-I and IGF-II were measured every 2nd hour (acromegalic patients) or every 4th hour (GH deficient patients). IGF binding protein (IGFBP)-1 was measured every 2nd hour (acromegalic patients) or every hour (GH deficient patients). RESULTS: In the untreated acromegalic patients there was a significant nocturnal decrease in free IGF-I, but not free IGF-II, before treatment. During treatment there was a significant nocturnal decrease in both free IGF-I and free IGF-II. Peak values of free IGF-I were 112% and 75% above trough (treatment and withdrawal, respectively). In the GH-deficient patients there were no significant circadian variations in free IGF-I or free IGF-II in either of the two occasions. In contrast, there was a significant circadian variation of total IGF-I after adjustment for changes in plasma volume in both treated and untreated acromegaly and GH deficiency in all cases with a peak between 0300 h and 0400 h. The nocturnal increase in total IGF-I ranged from 20% to 35%. CONCLUSIONS: A significant circadian variation in free IGF-I and IGF-II was demonstrated in acromegalic patients. In contrast no significant circadian variation in free IGF-I and IGF-II was found in GH-deficient patients. Part of the variations may be due to poorly understood variations in IGF-I release. It is not clear whether and to what extent the observed circadian changes in free and total IGF-I are involved in circadian changes in IGF-I bioactivity.

Acromegaly↗

Relationship between blood pressure and glucose tolerance in acromegaly.

BACKGROUND: Hypertension represents a well-known risk factor for cardiovascular diseases. The pathogenesis of hypertension in acromegaly is commonly viewed as multifactorial, but the possible influence of metabolic disorders on blood pressure (BP) in affected patients is largely unknown. OBJECTIVE: The aim of the present study was to evaluate the impact of glucose metabolism abnormalities on BP values in a series of patients with active acromegaly. DESIGN: An open multicentre prospective study. PATIENTS: Sixty-eight patients with active disease, aged 47.5 +/- 11.7 years, have been studied. Thirty-nine had normal glucose tolerance (NGT), 16 impaired glucose tolerance (IGT) and 13 suffered from diabetes mellitus (DM). MEASUREMENTS: Mean clinical BP values were calculated as the mean of BP values obtained by sphygmomanometric measurement in three separate occasions and mean 24-h, diurnal and nocturnal systolic (SBP) and diastolic (DBP) values were obtained by 24-h ambulatory blood pressure monitoring (ABPM). RESULTS: Patient's age and the degree of glucose tolerance abnormalities were found to significantly and independently influence BP values. All clinical and ABPM SBP and DBP values significantly increased with age by linear regression (P < 0.02 for all BP values, 0.30 < or = R < or = 0.43), and the independent influence of this parameter on BP values was confirmed by mutivariate analysis. Similarly, the independent influence of glucose tolerance abnormalities on BP values was confirmed when introducing age as a covariable in a multivariate analysis, and patients with DM presented significantly higher clinical SBP and 24-h, diurnal and nocturnal SBP and DBP than patients with NGT (P < 0.02 for clinical SBP, P < 0.015 for all ABPM values, respectively). In addition, patients with DM showed significantly higher 24-h, diurnal and nocturnal DBP than those with IGT (P < 0.05 in all cases). In contrast, no significant difference was found between NGT and IGT patients. No significant influence of disease duration, BMI, GH, IGF-I, or fasting and 2-h post glucose load insulinaemia on BP values was observed. CONCLUSIONS: Abnormalities of glucose metabolism significantly contribute to increase systolic blood pressure and especially diastolic blood pressure in acromegalic patients. Careful control of blood pressure and of risk factors for developing systemic hypertension, with special reference to glucose tolerance, is mandatory to decrease cardiovascular morbidity and mortality in such patients.

Acromegaly↗

Growth hormone-releasing hormone (GHRH) and GHRH receptor (GHRH-R) isoform expression in ectopic acromegaly.

Bronchial endocrine neoplasms causing acromegaly due to ectopic production of growth hormone (GH)-releasing hormone (GHRH) have been reported. We describe the case of a 39-year-old man with clinical and biochemical acromegaly. Magnetic resonance imaging revealed an enlarged pituitary, which was confirmed histologically to harbour somatotroph hyperplasia. Further investigations identified a circumscribed central mass in the right lung which was surgically resected and histologically confirmed to be an endocrine tumour with strong immunopositivity for GHRH, synaptophysin and chromogranin; the lesion also exhibited mild positivity for peptide YY, calcitonin gene-related peptide (CGRP), glucagon-like peptide (GLP)-1, corticotrophin-releasing hormone (CRH), tyrosine hydroxylase, vasoactive intestinal peptide (VIP) and enkephalin. S100 protein was identified in stellate cells surrounding nests of epithelial tumour cells. The MIB-1 antibody labelled about 10% of the tumour cells. We established that the tumour not only produced GHRH but the GHRH-receptor (GHRH-R) as well. GHRH and GHRH-R mRNA were identified and the latter was characterized as two variants, a full-length transcript and a truncated splice variant that has been described in human pituitary somatotroph adenomas. We suggest that GHRH expression by this tumour and the presence of its receptor may be responsible for enhanced growth. The expression of a truncated splice variant that is unable to transduce GHRH signalling may be implicated in the less aggressive behaviour of well-differentiated endocrine tumours that produce GHRH compared with small-cell lung carcinomas that are very responsive to GHRH growth stimulation.

Acromegaly↗