Prevalence of gastritis in patients with acromegaly: untreated and during treatment with octreotide

Agonists, Antagonists and Receptors of Somatostatin: Pathophysiological and Therapeutical Implications in Neoplasias

Somatostatin is a peptide that plays a variety of roles such as neurotransmitter and endocrine regulator; its actions as a cell regulator in various tissues of the human body are represented mainly by inhibitory effects, and it shows potent activity despite its physiological low concentrations. Somatostatin binds to specific receptors, called somatostatin receptors (SSTRs), which have different tissue distributions and associated signaling pathways. The expression of SSTRs can be altered in various conditions, including tumors; therefore, they can be used as biomarkers for cancer cell susceptibility to certain pharmacological agents and can provide prognostic information regarding disease evolution. Moreover, based on the affinity of somatostatin analogs for the different types of SSTRs, the therapeutic range includes conditions such as tumors, acromegaly, post-prandial hypotension, hyperinsulinism, and many more. On the other hand, a number of somatostatin antagonists may prove useful in certain medical settings, based on their differential affinity for SSTRs. The aim of this review is to present in detail the principal characteristics of all five SSTRs and to provide an overview of the associated therapeutic potential in neoplasias.

The effect of somatostatin analogs and acromegaly on the upper gastrointestinal system

PURPOSE

To evaluate the effects of somatostatin analogs and disease activity status on the upper gastrointestinal system in patients with acromegaly.

METHODS

One hundred eighty-one patients with acromegaly were retrospectively assessed. The demographic, biochemical, pathologic, and radiologic data of the patients were evaluated. The upper gastrointestinal endoscopies and endoscopic biopsies were investigated. We divided patients into four groups according to the use of somatostatin analogs, and into two groups according to disease activity. We compared the data of patients between groups A, B, C, and D, and controlled/uncontrolled groups separately.

RESULTS

Before and in the peri-endoscopic period, 67 and 27 patients were being treated with octreotide long-acting release (LAR) (group A) and lanreotide autogel (group B), respectively. Twenty-one patients used somatostatin analogs, but they were stopped for various reasons before upper gastrointestinal endoscopy (group C), and 66 patients did not use a somatostatin analog (group D). In the peri-endoscopic period, 103 (60%) patients were responsive to medical and/or surgical treatment and 67 (40%) patients were non-responsive. The rate of gastritis was higher in group A than in groups B and D. The incidence of duodenitis and gastric ulcer was much higher in group D. The rate of gastritis was higher in the controlled group compared to the uncontrolled group.

CONCLUSION

The study showed that octreotide LAR treatment could be a risk factor in addition to known factors for the development of gastritis in patients with acromegaly.

Evaluation of upper gastrointestinal system in acromegaly

PURPOSE

Acromegaly causes multiple comorbidities, including gastrointestinal disorders. The present study evaluated the frequency of hiatal hernia and other upper gastrointestinal pathologies in patients with acromegaly, given that visceromegaly and reduced nitric oxide levels in acromegaly may impact diaphragm and lower esophageal sphincter function and thus possibly the development of hiatal hernia.

METHODS

Thirty-nine acromegaly patients followed our center for the previous 6months were recruited. Upper gastrointestinal endoscopy was performed once in all patients to evaluate hiatal hernia, esophagitis, gastroduodenitis and ulcer.

RESULTS

Twenty-three patients were male and 16 female. Upper gastrointestinal endoscopy found hiatal hernia, esophagitis and gastroduodenitis or gastric ulcer in 3 (7.6%), 2 (1.7%) and 31 (79.4%) patients, respectively. Pathologic examination of gastric antrum biopsy found intestinal metaplasia in 12 (30.7%) patients, and Helicobacter pylori was positive in 13 (33.3%). There were no significant correlations between age, gender, disease duration or preoperative adenoma size on the one hand and hiatal hernia or other endoscopic findings on the other. Similarly, neither surgical success nor recurrence was associated with endoscopic findings.

CONCLUSIONS

The study showed that prevalence of gastritis, duodenitis, peptic ulcer and intestinal metaplasia is higher and prevalence of hiatal hernia lower in acromegaly patients than in the healthy population. Various unknown disease-related pathophysiological conditions may play a role; there is a need for further studies.

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.

Prevalence of Helicobacter pylori in acromegalic patients during treatment with octreotide

BACKGROUND

Octreotide, a synthetic long-acting analogue of somatostatin, now has an established role in the treatment of acromegaly. In acromegalic patients treated with octreotide there is an increased incidence of gallstones and possibly gastritis.

OBJECTIVES

(1) To compare the seroprevalence of Helicobacter pylori (H. pylori) infection, in acromegalic patients treated with octreotide to that in patients given other treatment modalities. (2) To study retrospectively the temporal relation between H. pylori acquisition and octreotide treatment.

PATIENTS

Three groups of acromegalic patients were studied; 35 (20 M) had been treated with octreotide, 17 (10 M) with bromocriptine and 19 (12 M) had received no pharmacological intervention (untreated, surgically treated or treated with radiotherapy).

DESIGN/MEASUREMENTS

The presence of H. pylori infection was assessed serologically (Bio-Rad GAP test for IgG), using stored serum, on the most recent sample from each patient and on serial samples from patients treated with octreotide.

RESULTS

The prevalence of H. pylori seropositivity was similar in each treatment group, 34, 35 and 37%, respectively. Mean age and duration of acromegaly were similar in the first two groups. Patients who had never received medical treatment were slightly younger. GH levels were similar in all three groups. Patients on octreotide who were seropositive for H. pylori did not differ from those with negative serology with respect to age, duration of acromegaly, duration of octreotide treatment or serum GH level. Serial samples in octreotide treated patients showed a change in status in only one patient; 18 patients continued with negative serology during a mean period of 30 (range 4-62) months. In each of the 6 patients with persistently positive serology during octreotide treatment, stored samples predating octreotide therapy were shown to have already been positive.

CONCLUSIONS

The seroprevalence of H. pylori infection in acromegalic patients does not appear to be increased in a manner dependent on the type or duration of medical treatment. In particular, octreotide therapy, while causing the development of histological gastritis in some patients, does not appear to induce the development of H. pylori infection.