The Effect of Amino-Bisphosphonate Therapy on Gingival Crevicular Fluid Alkaline Phosphatase Activity in Cancer Patients

Abstract

The enzyme Alkaline Phosphatase (ALP) is considered a biomarker of bone formation and it is used for monitoring intravenous Bisphosphonate (BP) therapy. It can be measured in serum and urine, but also in Gingival Crevicular Fluid (GCF). The aim of the present study was to monitor the GCF-ALP activity fluctuations in cancer patients before and during the first six months of BP therapy, comparing them with systemic serum ALP concentrations. 33 patients and 25 controls were enrolled according to the eligibility criteria. The GCF was collected at baseline, and after every BP administration for 6 times. The total ALP activities were determined spectrophotometrically. The results show how the differences in GCF-ALP activity over time appear to be significant in the BP-taking group (p=0.003), while the differences in serum ALP in the BP-taking group and in GCF-ALP activity in the control group were not significant (p>0.05). GCF-ALP activity may thus represent a possible new biomarker for bone turnover rate evaluation in patients taking intravenous BP therapy. Up to date, this is the first study that investigates on variations of GCF-ALP activity due to changes in bone metabolism caused by intravenous nitrogen-containing BP therapy in cancer patients.