[Role of bones in the physiopathology of idiopathic hypercalciuria: effect of amino-bisphosphonate alendronate].
Previous studies from our laboratory demonstrated that bone mineral content is affected in patients with idiopathic hypercalciuria and that there is a correlation between bone mineral loss and in-vitro cytokine production. At the same time we found that short term treatment with alendronate decreased urinary calcium in these subjects. In the present study we have examined the long-term effects of alendronate treatment (10 mg/day for one year) on urinary calcium, urinary hydroxyproline and bone mineral content in 18 idiopathic hypercalciuric and 8 normocalciuric stone formers. Clinical characteristics, as well as gender and age distribution were similar in both groups. Urinary calcium and hydroxyproline, were measured monthly. Calcium excretion decreased significantly at the end of the first month, and remained lower thereafter (277 +/- 28, before vs. 202 +/- 26 mg/g creatinine, after 12 months on alendronate, p < 0.01). Urinary hydroxyproline decreased significantly during the study (125.5 +/- 32.1 vs. 39.66 +/- 17.5 mg/g creatinine, p < 0.05). Serum calcium, glomerular filtration rate, and urinary sodium, did not change during the study. Lumbar spine bone density (trabecular bone) obtained with X ray absorptiometry revealed a significant increase from 1.162 +/- 0.231 to 1.197 +/- 0.248 g/cm2 (p < 0.01). These changes were associated with a significant decrease in IL-1 alpha mRNA transcription by unstimulated and lipopolysaccharide stimulated blood mononuclear cells, as tested by the reverse transcriptase polymerase chain reaction. No changes were observed in bone cortical sites (femoral neck). Normocalciuric subjects showed no significant changes in urinary calcium. In summary, the changes observed in urinary calcium excretion and different bone metabolic parameters, suggest a role of bone in the pathophysiology of idiopathic hypercalciuria.
Weisinger
J R
JR
Servicio de Nefrología y Transplante Renal, Hospital Universitario de Caracas, Venezuela.
Alonzo
E
E
Machado
C
C
Carlini
R
R
Martinis
R
R
Paz-Martínez
V
V
Bellorín-Font
E
E
D019386:Alendronate / Q000627:therapeutic use*; D015519:Bone Density / Q000502:physiology*; D001862:Bone Resorption; D001842:Bone and Bones / Q000378:metabolism / Q000502:physiology*; D002118:Calcium / Q000378:metabolism / Q000652:urine*; D016207:Cytokines / Q000502:physiology; D006801:Humans; D006909:Hydroxyproline / Q000378:metabolism / Q000652:urine*; D014545:Urinary Calculi / Q000150:complications
D016207:Cytokines; D006909:Hydroxyproline; D002118:Calcium; D019386:Alendronate