Gnudi S

Proximal Femur Geometry To Detect and Distinguish Femoral Neck Fractures from Trochanteric Fractures in Postmenopausal Women

Abstract: Some proximal femur geometry (PFG) parameters, measured by dual-energy X-ray absorptiometry (DXA), have been reported to discriminate subjects with hip fracture. Relatively few studies have tested their ability to discriminate femoral neck fractures from those of the trochanter. To this end we performed a cross-sectional study in a population of 547 menopausal women over 69 years of age with femoral neck fractures (n= 88), trochanteric fractures (n= 93) or controls (n= 366). Hip axis length (HAL), neck–shaft angle (NSA), femoral neck diameter (FND) and femoral shaft diameter (FSD) were measured by DXA, as well as the bone mineral density (BMD) of the nonfractured hip at the femoral neck, trochanter and Ward’s triangle. In fractured subjects, BMD was lower at each measurement site. HAL was longer and NSA wider in those with femoral neck fractures. With logistic regression the age-adjusted odds ratio (OR) for a 1 standard deviation (SD) decrease in BMD was significantly associated at each measurement site with femoral neck fracture (femoral neck BMD: OR 1.9, 95% confidence interval (95% CI): 1.4–2.5; trochanter BMD: OR 1.6, 95% CI 1.2–2.0; Ward’s triangle BMD: OR 1.7, 95% CI 1.3–2.2) and trochanteric fracture (femoral neck BMD: OR 2.6, 95% CI 1.9–3.6; trochanter BMD: OR 3.0, 95% CI 2.2–4.1; Ward’s triangle BMD: OR 1.8, 95% CI 1.4–2.3). Age-adjusted OR for 1 SD increases in NSA (OR 2.2, 95% CI 1.7–2.8) and HAL (OR 1.3, 95% CI 1.1–1.6) was significantly associated with the fracture risk only for femoral neck fracture. In the best predictive model the strongest predictors were site-matched BMD for both fracture types and NSA for neck fracture. Trochanteric BMD had the greatest area (0.78, standard error (SE) 0.02) under the receiver operating characteristic curve in trochanteric fractures, whereas for NSA (0.72, SE 0.03) this area was greatest in femoral neck fractures. These results confirm the association of BMD with proximal femur fracture and support the evidence that PFG plays a significant role only in neck fracture prediction, since NSA is the best predictive parameter among those tested.

L-Arginine and L-Lysine stimulation on cultured human osteoblasts

Essential amino acids, such as L-Arginine (Arg) and L-Lysine (Lys), are involved in bone metabolism and growth. Our previous studies analyzed the effect of these amino acids on rat osteoblast cultures and in experimental animals. In this study, we evaluated the effect of L-Arg and L-Lys on cultured human osteoblasts. Primary human osteoblast cultures were divided into four groups: the Arg Group received 0.625 mg/ml per day of Arg, the Lys Group 0.587 mg/ml per day of Lys, the Arg-Lys Group received both amino acids, whereas the Control Group was sham-treated. After 7 days, the following parameters were tested in all groups: alkaline phosphatase (ALP), nitric oxide (NO), calcium (Ca), phosphorus (P), osteocalcin (OC), type I collagen (PICP), interleukin-6 (IL-6), transforming growth factor-beta 1 (TGF-beta 1) on culture supernatant, platelet derived growth factor (PDGF), insulin-like growth factor-I (IGF-I), and MTT proliferation test on cells. Arg administration significantly increased ALP, NO, PICP and IGF-I production and reduced the level of IL-6. Lys administration over the same time interval mainly affected cell proliferation, as evidenced by the MTT test and immunostaining for PDGF. The same positive effects evidenced by the single administrations of the two amino acids resulted from their simultaneous administration. However, synergism could be demonstrated only for the decrease in the level of IL-6. Arg and Lys show a positive effect on human osteoblasts, which is related partly to the production of those factors required for matrix synthesis, and partly to the direct or mediated activation of cell proliferation.

Comparison of calcitonin, alendronate and fluorophosphate effects on ovariectomized rat bone

The effects of calcitonin, alendronate and fluorophosphate preventive treatment on ovariectomized rat femur were studied by comparing densitometric, mechanical, mineralogical and histomorphometric data. Sixty retired breeder female Sprague-Dawley rats, aged 10 months, were randomly divided into six groups. A group (baseline) was euthanized at the beginning of the study as a baseline group; four groups were ovariectomized and one was sham-operated (sham) and considered as a sham-aged group. A group of ovariectomized rats was used as a sham-therapy control (OVX) and received only deionized drinking water, while the other three received: a) salmon calcitonin (SCN) at a dose of 2 IU/kg/d s.c. (OVX + SCN); b) alendronate sodium salt (ALN) at a dose of 6 microg/kg/d administered by gavage (OVX + ALN); and c) L-glutamine monofluorophosphate (G-MFP) and calcium at a rate of 1:30 F/Ca at a dose of 0.21 mg F/6.30 mg Ca per kg/d by gavage (OVX + MFP). Significant increases (P < 0.05) of about 15 and 27% in femoral proximal epiphysis bone mineral density (BMD) of the OVX + ALN group were observed versus healthy groups and the OVX group, respectively. The OVX + ALN group also showed significant increases in femoral mid-diaphysis BMD when compared to OVX (18%, P < 0.001), OVX + SCN (14%, P < 0.05) and OVX + MFP (18%, P < 0.001) groups. In the OVX + MFP group, the three-point bending test demonstrated significant increases (P < 0.05) in maximal load of 21 and 22% when compared to the OVX and OVX + SCN groups, respectively. Also, stiffness data showed significant increases of the OVX + MFP (17%) and sham (14%) groups in comparison with the OVX group. A decrease in Mg (42%, P < 0.05), and increases in Ca (15%, P < 0.0001) and PO4 (8%, P < 0.005) content were found by comparing OVX + MFP and OVX groups. Trabecular bone volume results showed significant increases by comparing OVX + ALN and OVX groups (12.20%, P < 0.0005), as well as control groups. Tested agents were able to reduce the bone loss due to estrogen deficiency, but this did not always produce an increase in strength of the treated bone. Alendronate treatment prevented a decrease in bone mineral density and maintained bone mechanical properties after ovariectomy without impairment of bone mineralization in aged rats.

Discriminant capacity of quantitative ultrasound versus dual X-Ray absorptiometry to determine cancellous bone loss in ovariectomized rats

The capacity of dual x-ray absorptiometry and quantitative ultrasound to discriminate bone loss and to predict the mechanical and microarchitectural properties of cancellous bone in an animal model of osteopenia was evaluated. Thirty-five female Sprague-Dawley rats (10 months old) were randomized into three groups: baseline group, 10 rats killed at the beginning of the study; ovx group, 15 rats ovariectomized; and sham group, 10 rats sham operated. At the beginning and end of the study, all the animals underwent osteosonography to record the proximal tail (C3 vertebra) bone speed of sound. Sixteen weeks after surgery, the animals were euthanized and the L5-6 lumbar vertebrae of each rat were excised for densitometric, biomechanical (compression test), and histomorphometric studies. Significant differences were found among the groups for final speed of sound (p = 0.01). The L5 bone mineral density of the ovx group decreased by 12.1% (p = 0.049) and 12.6% (p = 0.035) compared, respectively, with baseline and sham groups. The biomechanical parameters of the ovx group decreased by 15-47% compared with the other groups, showing significant differences between the ovx and sham groups both for maximal stress (p = 0.026) and elastic modulus (p = 0.013). Histomorphometric parameters of the ovx group showed significant decreases in comparison with other groups. Logistic regression analysis showed that dual X-ray absorptiometry and quantitative ultrasound discriminate ovariectomized and healthy rats with a similar capacity, classifying correctly all rats used in the model in a range of 61-70%. This similar capacity seems to derive from two different capacities to detect bone changes. Dual X-ray absorptiometry, depending on bone mineralization and density, is able to detect modifications in bone stiffness and strength, confirmed also by the correlation with biomechanical data. On the contrary, quantitative ultrasound seems to depend more on cancellous bone microarchitecural changes because it is correlated to histomorphometric parameters.

The Mechanical Properties of Fluoride-Treated Bone in the Ovariectomized Rat

Abstract. The effect of fluoride therapy on the osteopenic bone of the ovariectomized rat was studied by comparing the densitometric and biomechanical data. Forty retired breeder female Sprague-Dawley rats aged 10 months were randomly divided into five groups. One group (Group A) was killed at the beginning of the study and was used as a baseline. Three groups were ovariectomized and one was sham-operated (Group B) and observed for the same period as a sham-aged group. A group of ovariectomized rats was used as a sham therapy control (Group C) and received only deionized drinking water; the other two groups (F1 and F2) received L-glutamine monofluorophosphate and calcium at a rate of 1:30 F/Ca at different doses by gavage (0.57 mg F/17 mg Ca per kg/day-Group F1; 0.21 mg F/6.30 mg Ca per kg/day-Group F2). Densitometric and biomechanical (compression and three-point bending test) assays, X-ray diffraction, and Fourier transformed infrared spectroscopy were performed on femoral specimens. Biomechanical data showed that the femoral heads of Group F2 required a significantly greater energy-to-failure than Group C (P < 0.05) as well as treated femoral diaphysis when compared with the others (P < 0.01). Significant increases in the elastic modules were observed in fluoride-treated groups (P < 0.001) when compared with other groups. Diffractometric and spectroscopic data showed the presence of fluorine-apatite in both treated groups with a high component of carbonates. Also, fluoride therapy causes an increase of bone stiffness due to the presence of fluoroapatite. It seems to produce two opposed properties in the osteopenic rat bone: a higher resistance to compression loading and a greater frailty to flexion loading.