Bone Abstracts

Recent studies have demonstrated the role of osteocalcin in energy metabolism regulation having a connection between this and bone metabolism. According to this, anti-osteoporotic drugs may exert different effects on energy metabolism. Thereby, our aim is to evaluate the effects of antiresorptive (Denosumab) and osteoanabolic (Teriparatide) drugs that reduce or increase respectively osteocalcin levels, on energy and bone metabolism by assessing of undercarboxilated osteocalcin (ucOC), myostatin and sclerostin levels.

We performed a prospective study of 3 months duration in patients with postmenopausal osteoporosis who are treated with two different antiosteoporotic drugs: i) dose of 60 mg Denosumab semiannually (n=22) compared to ii) 20 μg Teriparatide s.c. daily (n=16).

We measured the percent change from baseline in serum ucOC, sclerostin and myostatin levels as main parameters of study, and total OC, P1NP, CTX and PTH as secondary measurements, at first week, first and third months.

Serum ucOC levels were significantly lower in Denosumab group and significantly higher in Teriparatide group at first and third month compared to baseline (12.4, 47.8% vs 117, 87% respectively; P<0.05); serum sclerostin levels were increased but not significantly in Denosumab group and decreased in Teriparatide group at first week, first and third months (2.9, 10.6, 8.5% vs 0.7, 3.8, 1.9% respectively; P>0.05); however, there were significative differences between groups at first month (P<0.05). Serum myostatin levels remained unchanged. Bone markers were significantly decreased in Denosumab group and increased in Teriparatide group at all measurements with significative differences between groups (P<0.05). PTH levels were significantly increased at first and third month in Denosumab group (65 and 21.5% respectively, P<0.05) with significative differences between groups (P<0.001).

These preliminary results show an opposite effect of denosumab and teriparatide on Wnt signaling leading to a decrease or increase in serum ucOC levels and bone turnover markers respectively.