Bearing in mind earlier studies which established a link between arteriosclerosis and mineral loss, or fragility of the bones, and also our recent study showing that patients with arterial disorders of the lower limbs also suffered from osteoporosis, we carried out a histological study of the number and appearance of the intraosseous vessels and trabecular bone volume in the femoral heads of patients undergoing surgery for either fracture of the femoral neck or osteoarthritis of the hip. The number of thick-walled vessels, arterioles or arterial capillaries was significantly diminished in the femoral heads of patients with fractures of the femoral neck (p = 0.007). In addition, in the latter patients, arteriosclerotic vascular lesions (rupture of the internal elastic lamina, medial thickening and fibrosis) were more frequent than in patients with osteoarthritis of hip. The possibility that, through chronic ischemia, arteriosclerosis may lead to disturbance of bone remodelling and loss of the mechanical properties of bone has not been contradicted by these findings.

Bone vessel lesions were the same in the three groups.

Several studies have shown that the number of intratumoral vessels can predict the aggressiveness of a solid cancer, development of metastases and patient survival. Does angiogenesis play an important role in myeloma? The aim of our study was to quantify bone marrow vascularity in various stages of proliferative plasma cell disorders (monoclonal gammopathies of undetermined significance (MGUS), stage I multiple myeloma (MM), stage III MM and Waldenström's macroglobulinemia (WM)) and to compare it with that of patients with osteoporosis. The study included 15 MGUS patients, 15 patients with stage I MM, 15 patients with symptomatic stage III MM, 7 patients with WM, 10 patients with osteoporosis, and 10 patients with reactive bone marrow (RBM), matched for sex and age. After iliac crest biopsy, the various vessels (arterioles, capillaries and sinusoids) were labeled with monoclonal antibodies CD34 and counted, and a histomorphometric study was done. The number of arterioles and arterial capillaries was significantly increased in MGUS and myeloma compared with osteoporosis. The number of arterioles and arterial capillaries increased moderately according to the stage of gravity of myeloma. The number of arterioles is negatively correlated with the trabecular bone volume and positively correlated with the eroded surfaces.

In order to study the action of tiludronate on the changes in intraosseous vascularization induced by ovariectomy, and to link these effects to those observed in bone remodelling, 30 female Sprague-Dawley rats (age 40 weeks) were studied. Ten rats were shamoperated and treated by vehicle, 10 rats were ovariectomized and treated by vehicle, and 10 rats were ovariectomized and treated orally with tiludronate, 0.16 mmol/kg/per day, 3 days a week for 16 weeks, from the day following ovariectomy. The rats were killed after 4 months, and a histomorphometric study and quantification of intraosseous vessels carried out on the sixth lumbar vertebra. The area of the intraosseous sinusoidal capillaries increased after ovariectomy, which also induced a moderate increase in resorption surfaces and osteoid surfaces leading to a decrease of 40% in the trabecular bone volume at the lumbar spine level. This bone mineral loss was completely prevented by tiludronate, which normalized the bone turnover. However, tiludronate was without any effect on intraosseous vascularization. These results indicate that the surface area of the intraosseous sinusoidal capillaries was correlated positively with resorption surfaces and negatively with trabecular bone volume and the number of bone trabeculae. In these experimental conditions, an inhibitor of bone resorption can exert its positive effect on bone mass without normalization of vascularization.

The authors studied by light microscopy the vessels of the femoral head and neck in 38 well preserved specimens from core biopsy. There were 17 cases of osteonecrosis (ON), 11 cases of osteoarthrosis (OA) and 10 cases of reflex sympathetic dystrophy, so called algodystrophy (AD). Mean age of the patients was respectively 44, 45 and 42 years. The sex ratio, M/F, was respectively 12/5, 6/5 and 9/1. Types of staining used were hematoxylin-eosin, Masson Trichrome, P.A.S. and Verhoeff. In counting, thick-walled and thin-walled vessels were distinguished. There was a significant reduction in the number of the thick- and thin-walled vessels, in the ON group, by comparison with the OA and AD groups. An increased number of thin-walled vessels in the AD group were also observed. Morphological study showed an abnormal frequency of fibrosis of the media in the arteries of the ON group, i.e. arteriosclerosis. These data were compared with the few other histopathological studies previously published. The authors recommend further studies in order to precise their frequency and their significance.