Aurélio Borelli

Brazilian normal static bone histomorphometry: effects of age, sex, and race

Bone histomorphometry values for normal individuals within different populations have been well established. We studied iliac crest bone samples from 125 healthy Brazilian subjects. The effect of sex, race, and age variables on histomorphometric parameters was evaluated. Bone volume showed a trend to decrease with age in both sexes, being significantly higher in black females and Caucasian males. Interactions among sex, race, and age had no effect on trabecular thickness (Tb.Th) and trabecular separation (Tb.Sp). However, age had a significant effect on Tb.Th and Tb.Sp, and sex had an impact on Tb.Sp. Trabecular number (Tb.N) was higher in black females than in males and was higher in Asian males than in females. Among females, Tb.N was lower in Asians than in other races and was higher in blacks than in Caucasians and or in those of mulattos. In addition, Tb.N was higher in males under 10 than in males over 50 years old, was higher in females under 10 than in females in any other age bracket, and was lower in females in the 41–50 age bracket than in younger females. Osteoid volume and osteoid surface were significantly higher in males than in females, and a significant age-related difference in osteoid thickness was observed. No significant sex-related or race-related differences were found in terms of resorption, although eroded surface decreased with age. In conclusion, sex, race, and age, as well as interactions among these three variables, were found to affect some static histomorphometric indexes in healthy Brazilian subjects.

Reversal of Aluminum-Related Bone Disease after Renal Transplantation

We evaluated the course of severe aluminum-related bone disease (ARBD) after the first year of a successful renal transplantation (RTx) in 11 adult patients. Bone pain and muscle weakness, presented in all patients previously to RTx, subsided, and all were able to walk, even the ones who were confined to wheelchairs. Bone necrosis developed in 6 patients, but none required surgical repair. Serum alkaline phosphatase activity increased 2.5 times the upper normal level, up to the 5th month and then declined to normal levels up the 12th month (p < 0.05). The inverse profile was observed in both serum calcium and phosphorus levels. In bone biopsies, there was a significant decrease in all of the following histomorphometric static parameters: osteoid volume, thickness and surface and also in aluminum surface. Also, there was a significant increase in all the dynamic parameters of mineralization: mineral apposition rate, mineralization surface, bone formation rate and adjusted apposition rate. In conclusion, ARBD remarkably improves after 1 year of successful RTx.

Improvement of adynamic bone disease after renal transplantation

Low bone remodeling and relatively low serum parathyroid hormone (PTH) levels characterize adynamic bone disease (ABD). The impact of renal transplantation (RT) on the course of ABD is unknown. We studied prospectively 13 patients with biopsy-proven ABD after RT. Bone histomorphometry and bone mineral density (BMD) measurements were performed in the 1st and 12th months after RT. Serum PTH, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and osteocalcin were measured regularly throughout the study. Serum PTH levels were slightly elevated at transplantation, normalized at the end of the third month and remained stable thereafter. Bone biopsies performed in the first month after RT revealed low bone turnover in all patients, with positive bone aluminum staining in 5. In the 12th month, second biopsies were performed on 12 patients. Bone histomorphometric dynamic parameters improved in 9 and were completely normalized in 6, whereas no bone mineralization was detected in 3 of these 12 patients. At 12 months post-RT, no bone aluminum was detected in any patient. We also found a decrease in lumbar BMD and an increase in femoral BMD. Patients suffering from ABD, even those with a reduction in PTH levels, may present partial or complete recovery of bone turnover after successful renal transplantation. However, it is not possible to positively identify the mechanisms responsible for the improvement. Identifying these mechanisms should lead to a better understanding of the physiopathology of ABD and to the development of more effective treatments.

Bone histomorphometry in Cushing's syndrome

Bone involvement is a common finding in Cushing’s syndrome. The actions of corticosteroids on bone have been studied quite intensively but only a few studies of bone histomorphometry in this syndrome have been published. In this paper we present histomorphometric measurements of bone activity in 7 patients with a postoperative reevaluation in two. The results show irregular alterations on histomorphometric parameters with an increased bone resorption and decreased bone formation rate. After surgery the abnormalities changed towards normal.

Papel da histomorfometria óssea no diagnóstico diferencial da osteomalacia

A osteomalacia e uma doenca osteo-metabolica em que ha deficiente mineralizacao do osso, e e definida pela histomorfometria ossea por apresentar espessura do rebordo osteoide (O.Th) maior do que 15mm, e intervalo de tempo para mineralizacao (MLT) maior do que 100 dias. As principais etiologias de osteomalacia sao a deficiencia de acao da vitamina D e a hipofosfatemia. Neste trabalho, 14 pacientes com osteomalacia diagnosticados clinica e laboratorialmente foram divididos em dois grupos: 6 pacientes com deficiente acao de vitamina D e 8 hipofosfatemicos. Todos os pacientes apresentaram ao exame histomorfometrico aumento do O.Th e do MLT compativel com o diagnostico de osteomalacia. A superficie de reabsorcao ossea estava aumentada no grupo com deficiencia de acao da vitamina D. Em seis pacientes hipofosfatemicos, a superficie de reabsorcao ossea estava ausente, em um paciente dentro da normalidade mas em um paciente encontrava se aumentada. Conclusao: a histomorfometria dinâmica ossea atraves da analise dos parâmetros de formacao confirmam o diagnostico de osteomalacia, enquanto que os parâmetros de reabsorcao permitem uma orientacao etiologica.

Kidney transplant from a patient with idiopathic hypercalciuria.

A case of renal transplantation is presented in which the donor had idiopathic hypercalciuria. The hypercalciuria persisted in the donor, but was not observed in the recipient. This fact suggests that, in this case, the cause of the hypercalciuria is the intestinal hyperabsorption of calcium ions.