Elcatonin

Aim: To study the effect of repeated systemic injections of elcatonin (a synthetic analog of eel calcitonin) on the responses of rat femoral artery preparation to vasoactive drugs and to determine subtypes of muscarinic cholinoceptors involved in acetylcholine (ACh)-induced vasorelaxation in elcatonin-treated rats. Methods: Spontaneously hypertensive rats (SHR) were treated sc with elcatonin, 0.5 and 5 U/kg, 3 times a week for 2 weeks. Responses to vasoactive drugs were determined in helically cut strips of femoral arteries of these rats. Schild plot data for muscarinic cholinoceptor antagonists were obtained on these vascular strips, using ACh as an agonist. Results: Elcatonin did not alter systemic blood pressure and contractile responses of the femoral artery to KCl, norepinephrine, 5-hydroxytryptamine, and prostaglandin F(2alpha). Elcatonin attenuated isoproterenol-induced relaxation, increased ACh- and ATP-induced relaxations, and did not change relaxant responses to sodium nitroprusside and cromakalim in the femoral artery. Nitro L-arginine in the combination with tetraethylammonium (or charybdotoxin) completely abolished the relaxant response to ACh in the control but not in the elcatonin-treated arteries. The muscarinic cholinoceptor subtype involved in the ACh-induced relaxation was M3 in the elcatonin-treated as well as control SHR. Conclusion: Elcatonin decreases beta-adrenoceptor-mediated relaxation and increases M(3) cholinoceptor-mediated relaxation in the SHR femoral artery. Although the ACh-induced relaxation is explained by stimulated releases of nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) in the SHR artery, a NO-and EDHF-independent mechanism in addition to NO and EDHF is responsible for the response to ACh in the femoral artery from the elcatonin-treated SHR.

Background: Elcatonin (ECT) is used to prevent and treat osteoporosis. However, little is known about its effect on the disuse osteoporosis (DOP). The aim of this study is to evaluate the effect of ECT on DOP caused by fracture fixation. Methods: Forty-five male Sprague-Dawley (SD) rats, aged 6 weeks, were randomly allocated into three groups: the control group without surgery and elcatonin treatment (CTR, n = 15), the surgery group without elcatonin treatment (SUR, n = 15), and the surgery group which received elcatonin subcutaneously (SUR + ECT, n = 15). Surgery was produced by cutting the midshaft of the right femur transversely, fixing with stainless intramedullary needle, and immobilizing the right leg. All the proximal tibias from the random five rats in each group were harvested and investigated by evaluating bone mineral density (BMD), X-ray images, and histological staining respectively at the 4th, 8th, and 12th weeks after surgery. Results: Both of the SUR and SUR + ECT groups obviously exhibited lower BMD values compared to the CTR group; however, the SUR + ECT group showed significantly higher BMD values (p < 0.001, p < 0.05, and p < 0.05) than the SUR group at each time point after surgery. Moreover, similar changes were observed between these groups when examining the radiographs and hematoxylin and eosin (HE) staining. Conclusions: Elcatonin attenuates disuse osteoporosis after fractures in rats, which may provide a new avenue to prevent and treat disuse osteoporosis after surgery in clinic.

The present systematic review aimed to evaluate bone mineral density (BMD) change and complication rates of elcatonin on treating postmenopausal osteoporosis. The result confirmed efficacy of elcatonin and safety in combination therapies of elcatonin (C-E). Introduction: Postmenopausal osteoporosis is an important issue in global aging trends. One treatment of osteoporosis is elcatonin, a kind of calcitonin. However, it has been challenged for long time because of safety. Many trials investigated on this topic, but they were designed differently. Those designs can be categorized in monotherapy of elcatonin (M-E) and C-E. Unfortunately, no synthesized evidence dealt this topic. Methods: This study systematically identified target trials from six important databases and only included randomized controlled trial for synthesis. Two investigators assessed quality of eligible trials using the Cochrane Risk of Bias Tool, and they independently extracted data. Network meta-analysis performed Peto odds ratio (POR, used for dealing with zero cell) or weighted mean difference (WMD, for continuous data) with 95% confidence intervals (CI) and consistency H. Results: Sixteen trials recruiting 2754 women with postmenopausal osteoporosis were included in our study. Elcatonin therapies and non-elcatonin medications had comparable fracture rates and bone mineral density change. Yet, C-E (WMD, - 18.93; 95% CI, - 23.97 to - 13.89) and M-E (WMD, - 13.72; 95% CI, - 19.51 to - 7.94) had significantly lower pain score than non-elcatonin medications. However, M-E (POR = 8.413, 95% CI, 2.031 to 34.859) and non-elcatonin medication (Peto OR, 7.450; 95% CI, 1.479 to 37.530) had significantly higher complication rates than placebo. No evidence detected inconsistency and small study effect in this network model. Conclusions: Based on current evidence, C-E may be considered for treating postmenopausal osteoporosis because it benefits on pain relief and complications. Moreover, it shows comparable fracture rate and bone mineral density change as compared with anti-osteoporosis and calcium supplements. Nevertheless, further trials are needed to investigate formula and dosages of elcatonin.