F.C. van Ginkel

Histomorphometric profile and vitamin d status in patients with femoral neck fracture

Abstract In order to detect metabolic bone disease vitamin D metabolites and other biochemical parameters of bone metabolism were measured in 125 patients with femoral neck fracture and 74 age-matched control subjects. Transilial bone biopsies from 89 patients, obtained within 1 week of the fracture, were evaluated by histomorphometric techniques. Trabecular bone volume (TBV) was significantly lower in trochanteric fractures in both sexes than in controls, whereas in cervical fractures TBV was not decreased. Other histomorphometric differences between both fracture types were not observed. Cortical porosity was higher in the patients than in autopsy controls. The osteoid surface was extended in the patients, but the osteoid seams were significantly thinner than in controls. The mean width of osteoid seams was not increased in any patient. On these grounds serious osteomalacia is unlikely. With remodeling parameters the biopsies were classified into three subgroups: “high turnover” ( n =19), “uncoupling” between resorption and formation ( n =9), and a “rest” group ( n =61), in which bone turnover was normal or low. In the “high turnover” group mean cortical thickness was decreased significantly compared with the other groups. Mean serum concentrations of calcium (corrected for serum proteins), phosphate, creatinine, alkaline phosphatase, and parathyroid hormone were not different in patients and control subjects. Serum concentrations of the vitamin D metabolites 25(OH)D, 24,25(OH)2D, and 1,25(OH) 2 D were significantly lower in patients than in controls. The histomorphometric picture could not be predicted adequately by means of biochemical parameters. An increased osteoid volume (≥ 5%), and/or surface (≥ 25%), observed mainly in the “high turnover” group, was always associated with a serum 25(OH)D concentration below 30 nmol/l. The “high turnover” may follow vitamin D deficiency. The latter, however, does not cause a clear histological reaction in most cases.

The radiographic trabecular pattern of hips in patients with hip fractures and in elderly control subjects.

Due to the increasing number of osteoporotic fractures of hip, spine, and wrist there is a growing need for methods to track down the subjects with inferior bone structure and to monitor the effects of therapeutic measures. This study aims at a noninvasive diagnostic tool, deriving architectural properties of trabecular bone from in vivo measurements on plane radiographic films. Pelvic radiographs of the nonfractured hips of 81 patients with hip fractures and of the right hips of 74 controls were studied. The regions of interest, 2 x 2 cm2, located in the femoral neck, were sampled and digitized with a video camera connected to an image analysis system. Several geometrical and directional measurements were made. The measurements were evaluated by statistical comparison with fracture risk, gender, and Singh index. By discriminant analysis, type of fracture, as well as gender and Singh index could be predicted correctly for 58% of the subjects, whereas guessing would be correct in only 8%. It was found that the geometrical parameters discriminate between hips of controls and patients. With respect to the directional measurements associations were found with gender and Singh index. Although the new parameters assess fracture risk less accurately than bone density measurements, some parameters suggest by their behavior that they are relevant with respect to femoral bone architecture and its mechanical behavior. Although interpretation of the measurements in histological concepts requires methods that have been reported in literature only recently, it is concluded that digital analysis of the radiographic trabecular pattern is an interesting option to increase the diagnostic yield of plane film radiographs and to study the structure of bone in vivo.

Orientation of the trabecular pattern of the distal radius around the menopause

The trabecular pattern depicted on radiographs of the distal radius of women around the menopause is analysed by a new method to measure orientation. It is shown that the trabecular pattern on radiographs of the distal radius is aligned preferentially along the axial direction and to a lesser extent along the transverse direction. Two minima of orientation are found at 60 degrees off the axial direction. A significant correlation is found between the average value of the orientation in the radius and the average lumbar bone mineral density. It is known that the bone mineral content decreases around the menopause. Previous reports on the present images describe several features that were found to be related to bone mineral content and to time. The orientation of the trabecular pattern, however, is found to be independent of time, at least during the two years of the investigation. Therefore, it is concluded that the orientation of the radiographic trabecular pattern tends to remain stable even if some features of the pattern evolve. Previous studies on radiographs of the radius of children and elderly women and men provide evidence for the tendency of orientation to remain stable not only in women around the menopause, but also in men and women during the entire adult life.

Longitudinal analysis of radiographic trabecular pattern by image processing.

To describe structural and textural changes in bone structure, the radiographic trabecular pattern of children, aged 4-14 years, was examined using a digital image processing system. This investigation is based on data from the Nijmegen Growth Study, a mixed-longitudinal growth study comprised of three birth cohorts, which were observed for five years. Of 3075 left hand-forearm radiographs of 426 children, a standard area of 10 x 10 mm of the radius was digitized and the trabecular pattern was described by ten image features. It is demonstrated that all image features show significant changes during the observation period (multivariate analysis of variance of p < 0.01). The age of the children correlates significantly with the image features (Spearmans Rho = 0.4; p < 0.05). Because of cohort effects, the three cohorts were studied separately. Highest correlations between age and trabecular pattern were shown in the cohort of the youngest children. The changes of the image features during the observation period seems to indicate that the fine trabecular pattern of young children changes into a coarser adult pattern. It is concluded that digital quantification of the radiographic trabecular pattern is appropriate to describe changes in trabecular bone.

The effect of trauma on serum concentrations of vitamin D metabolites in patients with hip fracture

In a previous study we observed lower serum concentrations of 25(OH)D, 24,25(OH)2D, and 1,25(OH)2D in patients with hip fracture than in aged control subjects. In order to evaluate the effect of trauma on vitamin D metabolite levels, we measured serum concentrations of vitamin D binding protein (DBP) in 118 patients with hip fracture and 71 aged control subjects. Serum DBP was lower in the patients than in the controls (mean +/- SD 315 +/- 60 vs 371 +/- 44 mg/l, P less than 0.001). Serum DBP correlated positively with serum total protein, albumin, alpha 2-globulin, and the vitamin D metabolite levels in the patients. When correcting for differences in serum DBP, serum 25(OH)D and 24,25(OH)2D still were significantly lower in patients than in controls, whereas serum 1,25(OH)2D was not. The free 1,25(OH)2D index (10(5) x molar ratio 1,25(OH)2D/DBP) was lower in patients than in controls, but the level of significance was marginal. This difference was not significant when patients and controls with impairment of renal function were excluded. It is concluded that the difference in serum 25(OH)D and 24,25(OH)2D between patients and controls is largely preexistent. However, the lower serum 1,25(OH)2D in the patients is mainly caused by the trauma. The free 1,25(OH)2D concentrations are almost similar in the two groups when renal function is normal.

Intermittent compression stimulates cartilage mineralization.

The effects of intermittent hydrostatic compressive force (ICF; 13 kPa applied at 0.3 Hz frequency), as a substitute for moderate loading in vivo, on ossifying bone organ cultures, were evaluated by means of (histo)-morphometry. In earlier studies, biochemical tests have shown an increased 45Ca intake and an increased alkaline phosphatase activity in bone organ cultures that received ICF, suggesting that ICF promoted matrix mineralization. The purpose of this study was to examine whether an effect of ICF on mineralization can be described by means of histomorphometrical analysis. Fetal mouse metatarsal bone rudiments were cultured for 5 days in serum-free medium, with (experimental) or without (control) ICF. Linear measurements taken during culture demonstrated that the dark zone in the center of the rudiment, representing mineralized hypertrophic cartilage, became significantly longer in the group that received ICF when compared with the control group. This finding was in conformation with the former studies. Histological sections of the rudiments, stained with Goldners trichrome method were used to study changes at the cellular level and to describe the position and relative amount of mineralizing cartilage matrix (defined as Goldner-positive matrix [GPM]). Histomorphometry demonstrated that ICF treatment significantly increased the length of the hypertrophic cartilaginous zone and enhanced the amount of GPM between the mineralizing hypertrophic chondrocytes. However, the total length of the zone containing GPM was not increased, nor was the future bone collar, consisting of a thin osteoid seam, lengthened by ICF. These data indicate that the cellular processes involved in chrondrocyte hypertrophy were accelerated by ICF, as well as the extracellular processes leading to matrix mineralization. The study supports the earlier conclusion that embryonic bone rudiments are sensitive to mechanical stimulation and that moderate loading promotes their ossification in vitro.

Short-term effects of Org OD 14 and 17β-oestradiol on bone and lipid metabolism in early postmenopausal women

Abstract The effects of 8 weeks of daily oral treatment with I mg 17β-oestradiol (E 2 ), 2.5 mg Org OD 14 ((7α,17α)-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn-3-one), a steroid with weak androgenic, weak oestrogenic and weak progestational activity, or placebo on calcium and lipid metabolism were compared in 21 healthy, early post-menopausal women in a randomised double-blind study. The treatment period was followed by a treatment-free period of 8 weeks to study the reversibility of drug-induced effects. The results show that both E 2 and Org OD 14 reduce bone resorption, as indicated by the decreases in the urinary hydroxyproline/creatinine and calcium/creatinine ratios in 2-h fasting urine. In contrast to E 2 , Org OD 14 did not reduce serum calcium levels. As regards lipid parameters, E 2 reduced the concentration of serum cholesterol and Org OD 14 decreased serum levels of high-density-lipoprotein cholesterol and triglycerides. All these effects appeared to be reversible after cessation of treatment. It is concluded that both of these steroids reduce bone resorption in early post-menopausal women, but that their mechanisms of action are most likely different.

Patterns and relationships of plasma calcium, protein and phosphorus during the egg laying cycle of the fowl and the effect of dietary calcium

In 29 domestic hens, four blood samples were collected during the period of egg formation, at time points representing different metabolic stages. Plasma concentrations of total calcium, total phosphorus, inorganic phosphorus and total protein were measured, and the effect of adding oyster shell particles to a standard laying diet was investigated. Analyses of covariance were made and correlations between the plasma characteristics were calculated. The following were significantly correlated: total and inorganic phosphorus, calcium and total phosphorus, and calcium and protein. Each of the four characteristics showed a significant decrease during egg formation. Inorganic phosphorus reached a peak 15 h after ovulation, probably related to medullary bone resorption. Plasma total phosphorus differed significantly between chickens. Addition of oyster shell to the diet did not affect the concentration or the pattern of the plasma characteristics during egg formation and did not reduce calcium mobilisation from medullary bone during shell formation.

Histological and radiological quantification of estradiol-induced medullary bone formation and osteoclast activity in male quail

Medullary bone is a type of woven bone, normally found only in the marrow cavities of female egg-laying birds (Kyes and Potter, 1934). In young female birds, medullary bone formation is sttmulated by the synergistic action of androgens and estrogens. concomitant with the maturation of the ovarian follicles (Simklss, 1967). During eggshell calcification, medullary bone plays an important role as a calcium source (Mueller et al., 1964). In male birds, medullary bone can be induced by estrogen administration (Bloom et al., 1942). Tlmlng of osteoblast appearance and initial medullary bone formation has been described by Kusuhara and Schraer (1982) and Miller and Bowman (1981). However, these authors did not quantify the appearance of osteoblasts nor describe the osteoclastic aclvity. RadIological measurements were made after administratton of 4Ca and 99mTc-tm-methylene diphosphonate. gy-Tc(Sn)MDP is a radiopharmaceutical with a preferred localization in recently formed bone near osteoblastic zones (Gulllemart et al 1980; Savelkoul, 1984).