Bone remodelling in human immunodeficiency virus-1-infected patients. A histomorphometric study

Abstract The aim of this study was to identify and describe possible alterations of bone histomorphometry in patients with human immunodeficiency virus (HIV-1) infection and to assess the relation between these alterations and disease severity. Forty-four HIV-1-infected patients seen successively at our hospital were evaluated for the study. In an attempt to avoid confounding factors as far as possible, we excluded patients who fulfilled any of the following criteria: age less than 18 or greater than 40 years; recent history of extended bed rest; previous diagnosis of metabolic bone disease, renal insufficiency, or hepatic failure; clinical or echographic signs of liver cirrhosis; diabetes mellitus or previous diagnosis of other endocrine diseases; drug therapy that could act on bone metabolism; and/or moderate to severe nutritional alteration. Twenty-two patients (13 men, 9 women; age: 27.9 ± 4.1 years, mean ± standard deviation) were included in the study. Plasma and urine biochemistry and calcium-regulating hormones were determined. Bone mineral content was measured on vertebrae L2 to L4 and on the neck and intertrochanteric areas of the femur by dual-photon absorptiometry. A transiliac bone biopsy was performed after double-tetracycline labelling, with histomorphometric study of undecalcified bone. Serum osteocalcin was found to be lower in patients who, according to the Centers for Disease Control (CDC) classification, had greater disease severity, and showed a positive correlation with the number of CD4 + T lymphocytes. No alterations in bone densitometry were observed. Several histomorphometric parameters of bone formation and turnover and the number of osteoclasts were significantly lower in the patients than in the healthy controls (surface-based bone formation rate: 0.01 ± 0.01 μm 3 /μm 2 / day versus 0.04 ± 0.02 μm 3 /μm 2 /day, p = 0.05; activation frequency: 0.02 ± 0.03 year −1 versus 0.25 ± 0.13 year −1 , p = 0.004; osteoclast index: 0.02 ± 0.08 mm −2 versus 0.03 ± 0.04 mm −2 , p = 0.005). Several parameters of formation, such as surface-based bone formation rate, or of turnover, such as activation frequency, were lower in patients with greater disease severity according to the CDC classification and presented a positive correlation with the number of CD4 + T lymphocytes. No biochemical parameter of mineral metabolism or hormones, except osteocalcin, showed a correlation with disease severity. We conclude that HIV-1-infected patients in our series presented a notable decrease in bone formation and turnover. These changes appeared to be more marked in patients with more severe disease.