Postprandial response of bone turnover markers in patients with Crohn's disease.

AIM: To investigate the postprandial response of bone turnover markers in patients with Crohn's disease (CD). METHODS: Fifty nine patients with CD aged 38 ± 14 years, and 45 healthy individuals matched for age and body mass index were included in the study. All participants underwent an oral glucose tolerance test (OGTT) after an overnight fast and serum levels of the bone resorption marker C-terminal crosslinking telopeptide of type I collagen (CTX-I) and the bone formation marker procollagen type I N propeptide were measured. Activity of the disease was assessed by calculation of the Crohn's disease activity index (CDAI). RESULTS: Serum CTX-I was significantly higher in patients compared to controls (CTX-I: 453 ± 21 pg/mL vs 365 ± 25 pg/mL, P = 0.008), and values were significantly correlated with the activity of the disease (r = 0.435, P = 0.001). Results from OGTT-induced suppression of CTX-I showed two different trends. Patients with more active disease (assessed as CDAI > 150) had a more excessive suppression of CTX-I compared to controls (55% vs 43% P < 0.001), while patients on remission (assessed as CDAI < 150) demonstrated an attenuated CTX-I suppression (30% vs 43% P < 0.001). In line with this, CTX-I suppression after oral glucose load was significantly correlated with the activity of the disease (r = 0.913, P < 0.001). CONCLUSION: The physiological skeletal response of postprandial suppression of bone resorption is maintained in patients with CD and is strongly dependent to the activity of the disease.

The renin-angiotensin-aldosterone axis in patients with nontumoral [corrected] hyperprolactinemia.

OBJECTIVE: In physiological conditions, renin-angiotensin-aldosterone (RAA) axis is under continuous tonic inhibition by dopamine. The aim of this study was to evaluate the relationship of nontumoural hyperprolactinemia with the activity of adrenocortical and RAA axis, before and after administration of bromocriptine. DESIGN: Twenty women with nontumoural hyperprolactinemia and 20 healthy women matched for body mass index and age were recruited in this study. All participants were placed on fixed salt intake for 2 weeks before the experiments. The study was conducted in three phases. In phase I, the participants received an intravenous infusion of angiotensin II in three consecutive doses of 2, 4 and 6 ng/kg BW changed every 30 min. In phase II, the patients were started on bromocriptine in gradually increasing doses of 1.25, 2.5, 5, 7.5 and 10 mg/day for 10 weeks. In phase III, the protocol of phase I was repeated in the patient group. Circulating levels of cortisol, plasma renin activity (PRA), aldosterone and prolactin were assayed. RESULTS: Baseline values of prolactin, and PRA (2.6±0.18 nM vs 0.45±0.05 nM P<0.001 and 142.2±14.4 vs 30.7±2.7 pM/h, P<0.001, respectively) but not aldosterone (P=0.081) were significantly higher in the patient group. The angiotensin infusion test induced a significantly greater response in the patient group. Administration of the dopamine agonist restored the basal levels and diminished the response to angiotensin infusion for all the parameters tested. No change in the blood pressure was recorded. CONCLUSIONS: Our study demonstrates that in nontumoural hyperprolactinemia there is an increased reactivity of renin-angiotensin-aldosterone (RAA) axis that is almost completely restored after treatment with a dopamine agonist.