Successful neridronate therapy in pregnancy-associated osteoporosis.

Pregnancy-associated osteoporosis is a rare condition. The pathogenesis is probably multifactorial but has not yet been completely clarified. In this case report, a 38-year-old woman was referred to hospital after suffering an acute, non-traumatic back pain one month after delivering her first child. The radiological examination revealed four vertebral fractures. Bone mineral density was reduced, particularly at spine level. Biochemical tests were within normal range, except for increased urinary deoxypyridinoline and a slight reduction of the serum 25-OH vitamin D level. The patient was treated with neridronate, calcium and cholecalciferol. After one month, the patient was free of pain and DXA measurement after six months showed a marked recovery of bone mineral density at the spine and hip level.

When the FRAX(®) test is applied to controlled clinical trials.

FRAX(®) is a computer-based algorithm developed by the World Health Organization Collaborating Centre for Metabolic Bone Diseases in Sheffield (UK). This algorithm calculates fracture probability from easily obtained clinical risk factors in men and women: age, sex, body mass index and dichotomized variables comprising prior fragility fracture, parental history of hip fracture, current tobacco smoking, use of long-term oral glucocorticoid, rheumatoid arthritis, other causes of secondary osteoporosis and high alcohol consumption (femoral neck bone mineral density can be optionally input to enhance fracture risk prediction). The output of FRAX(®) is the 10-year probability of a major osteoporotic fracture (hip, clinical spine, humerus or wrist fracture) and the 10-year probability of hip fracture.Recently various Authors have re-evaluated the effectiveness of drugs approved for postmenopausal osteoporosis to test whether they are more effective in women with higher FRAX(®) probabilities.

Diagnosis of acute pyelonephritis by contrast-enhanced ultrasonography in kidney transplant patients.

BACKGROUND: Diagnostic imaging of acute pyelonephritis (APN) in renal transplanted patients is an important clinical issue. While conventional ultrasonography (US) has a limited diagnostic role, contrast-enhanced computer tomography and magnetic resonance imaging (MRI) represent the gold standard diagnostic tests. However, nephrotoxicity of either iodinated or paramagnetic contrast medium limits their use, especially in patients with kidney disease. Contrast-enhanced US (CEUS) may detect poorly perfused parenchymal renal areas, a useful feature in the diagnosis of APN. The aim of this study was to evaluate the diagnostic value of CEUS in APN compared with MRI as the reference test. METHODS: From a pool of 389 kidney transplant patients, we prospectively recruited 56 patients with clinical suspicion of APN of the transplanted kidney. They underwent both CEUS and MRI, performed in a blinded manner by two different operators. Sensitivity, specificity, accuracy, positive and negative predictive values, and K statistics were calculated. RESULTS: Thirty-seven out of 56 patients (66.1%) resulted positive for APN with the reference test, gadolinium-enhanced MRI. Thirty-five out of these 37 patients showed positive results for APN with CEUS, and 19 patients showed negative results for APN with both MRI and CEUS: sensitivity 95% (CI 82-99), specificity 100% (CI 83-100), accuracy 96% (CI 88-99), positive predictive value 100% (CI 90-100), negative predictive value 90% (CI 71-97) and K statistics 0.92 (P<0.01). CONCLUSIONS: Our results suggest, for the first time, the feasibility of CEUS, a low-cost and low-risk diagnostic procedure, in the diagnosis of APN in kidney transplant patients.

Persistent left superior vena cava: what the interventional nephrologist needs to know.

Variations in the course of the blood vessels are often incidental findings during clinical examination. Persistent left superior vena cava (PLSVC) is an uncommon anomaly, estimated to be present in about 0.3-0.5% of healthy individuals and in about 3-10% of patients with congenital heart disease. It results from the failure of the left anterior cardinal vein to degenerate during embryological development. Serious complications such as shock, angina and cardiac arrest have been described during catheterization in adults with a PLSVC. Since it frequently goes undiagnosed because of lack of symptoms when not accompanied by other anomalies, variations of the superior vena cava should be considered, especially when central venous catheterization via the subclavian or internal jugular vein is difficult. The embryological development, diagnosis, and clinical implications of a PLSVC are therefore reviewed in this article.

Guidelines for the management of osteoporosis and fragility fractures.

The purpose of this document, a result of the harmonisation and revision of Guidelines published separately by the SIMFER, SIOMMMS/SIR, and SIOT associations, is to provide practical indications based on specific levels of evidence and various grades of recommendations, drawn from available literature, for the management of osteoporosis and for the diagnosis, prevention, and treatment of fragility fractures. These indications were discussed and formally approved by the delegates of the Italian Scientific Associations involved in the project (SIE, SIGG, SIMFER, SIMG, SIMI, SIOMMMS, SIR, and SIOT).

Physical activity and bone turnover markers: a cross-sectional and a longitudinal study.

Strenuous physical activity in young individuals has an important effect on both bone mass and bone turnover but the effect of moderate physical activity in adults remains uncertain. In a large cohort (N = 530) of healthy premenopausal women, bone formation markers (osteocalcin and N-terminal propeptide of type 1 procollagen [P1NP]), but not serum C-telopeptide of type 1 collagen (sCTX), were found to be significantly associated with the level of physical activity, and this association remained significant after adjusting the data (ANCOVA) by age and body mass index. Mean spine and hip bone mineral density (BMD) values were positively associated with physical activity but this was statistically significant (P = 0.050) only for adjusted values of spine BMD. Twenty-four healthy sedentary premenopausal women, subscribing to participate in a community exercise program lasting a month, and 18 age-matched controls were included in the longitudinal study. Serum osteocalcin and P1NP, but not sCTX, rose significantly, by ca. 25%, only in the active group after a month of exercise. The changes in the two bone formation markers remained statistically significant for values adjusted for body weight, which fell significantly in the exercise group. In conclusion, both the cross-sectional and the longitudinal parts of our study demonstrate that even minor changes in physical activity are associated with a clear effect on bone formation markers.

Intramuscular neridronate in postmenopausal women with low bone mineral density.

Compliance to osteoporosis treatment with oral bisphosphonates is very poor. Intermittent intravenous bisphosphonate is a useful alternative, but this route is not readily available. Neridronate, a nitrogen-containing bisphosphonate that can be given intramuscularly (IM), was tested in a phase 2 clinical trial in 188 postmenopausal osteoporotic women randomized to IM treatment with 25 mg neridronate every 2 weeks, neridronate 12.5 or 25 mg every 4 weeks, or placebo. All patients received calcium and vitamin D supplements. The patients were treated over 12 months with 2-year posttreatment follow-up. After 12-month treatment, all three doses were associated with significant bone mineral density (BMD) increases at both the total hip and spine. A significant dose-response relationship over the three doses was observed for the BMD changes at the total hip but not at the spine. Bone alkaline phosphatase decreased significantly by 40-55% in neridronate-treated patients, with an insignificant dose-response relationship. Serum type I collagen C-telopeptide decreased by 58-79%, with a significant dose-response relationship (P < 0.05). Two years after treatment discontinuation, BMD declined by 1-2% in each dose group, with values still significantly higher than baseline at both the spine and the total hip. Bone turnover markers progressively increased after treatment discontinuation, and on the second year of follow-up the values were significantly higher than pretreatment baseline. The results of this study indicate that IM neridronate might be of value for patients intolerant to oral bisphosphonates and unwilling or unable to undergo intravenous infusion of bisphosphonates.

Sclerostin is a possible candidate marker of arterial stiffness: Results from a cohort study in Catania.

Osteoporosis and cardiovascular disease are worldwide public health issues. Recent evidence indicates a possible role of the canonical Wnt/ß-catenin signalling pathway as a common mediator between these two diseases. The aim of the present study was to investigate the relationship between serum concentrations of sclerostin and Dkk1, two extracellular inhibitors of Wnt/ß-catenin signalling, with carotid intima-media thickness (CIMT) and with arterial stiffness, evaluated by measuring the pulse wave velocity (PWV) in an ambulatory population of adults. To this aim, 67 subjects were recruited in the 'Atherosclerosis and osteoporosis: identification of common pathogenetic factors' investigation. Serum sclerostin levels correlated positively with CIMT (r=0.314, p=0.03) and inversely with the augmentation index, a marker of arterial stiffness (r=-0.286, p<0.05), whereas Dkk1 did not. Moreover, in a multivariate linear regression model, sclerostin [ß -0.1472; p=0.0023; standard error (SE)=0.04620] was an independent predictor of PWV in the study subjects. Our study shows that, following adjustment for confounders, sclerostin is an independent predictor of arterial stiffness in an ambulatory population, whereas Dkk1 is not.

In postmenopausal female subjects with type 2 diabetes mellitus, vertebral fractures are independently associated with cortisol secretion and sensitivity.

CONTEXT: In type 2 diabetes (T2D), the vertebral fracture (VFx) prevalence and cortisol secretion are increased. OBJECTIVE: The objective of this study was to evaluate the role of glucocorticoid secretion and sensitivity in T2D-related osteoporosis. DESIGN AND SETTING: This was a case-control study in an outpatient setting. PATIENTS: The patients were ninety-nine well-compensated T2D postmenopausal women (age, 65.7 ± 7.3 y) and 107 controls (age, 64.5 ± 8.2 y). MAIN OUTCOME MEASURES: We assessed osteocalcin, C-terminal telopeptide of type I collagen, ACTH, cortisol after the dexamethasone suppression test (F-1mgDST), BclI and N363S single-nucleotide polymorphisms (SNPs) of glucocorticoid receptor, lumbar spine and femoral neck bone mineral density by dual x-ray absorptiometry, and VFx by radiography. RESULTS: Compared with controls, T2D subjects had increased VFx prevalence (20 vs 34.3%, respectively; P = .031), bone mineral density (Z-scores, lumbar spine, 0.16 ± 1.28 vs 0.78 ± 1.43, P = .001; femoral neck, -0.03 ± 0.87 vs 0.32 ± 0.98, P = .008, respectively), and F-1mgDST (1.06 ± 0.42 vs 1.21 ± 0.44 µg/dL, 29.2 ± 1.2 vs 33.3 ± 1.2 nmol/L, respectively; P = .01), and decreased osteocalcin (10.6 ± 6.4 vs 4.9 ± 3.2 ng/mL, 10.6 ± 6.4 vs 4.9 ± 3.2 µg/L, respectively; P < .0001) and C-terminal telopeptide of type I collagen (0.28 ± 0.12 vs 0.14 ± 0.08 ng/mL, 0.28 ± 0.12 vs 0.14 ± 0.08 mcg/L, respectively; P < .0001). Fractured controls or T2D patients had increased sensitizing N363S SNP prevalence (20 and 17.6%, respectively) compared to non-fractured subjects (3.4 and 3.1%, respectively; P = .02 for both comparisons), and similar BclI SNP prevalence. The VFx presence was associated with the sensitizing variant of N363S SNPs in controls (odds ratio [OR] = 10.6; 95% confidence interval [CI], 1.8-63.3; P = .01) and in T2D patients (OR = 12.5; 95% CI, 1.8-88.7; P = .01), and with the F-1mgDST levels (OR = 2.1; 95% CI, 1.1-4.1; P = .03) only in T2D patients. CONCLUSIONS: In postmenopausal T2D women, VFx are associated with cortisol secretion and the sensitizing variant of N363S SNPs.

Exaggerated endothelin release in response to acute mental stress in patients with intermittent claudication.

Endothelin-1 (ET-1) is an endothelial-derived 21-amino-acid peptide with potent vasoconstrictor and mitogenic properties implicated in several cardiovascular disorders. To evaluate the plasma ET-1 response to mental stress in patients with intermittent claudication, plasma endothelin concentrations were measured by radioimmunoassay in 15 claudicant outpatients (13 men and 2 women; mean age 62 +/- 4 years) and in 15 sex- and age-matched healthy control subjects (12 men and 3 women; mean age 60 +/- 8 years) before and after mental arithmetic performed for 10 minutes. Venous blood samples were drawn from an antecubital vein at baseline, at the end of the mental arithmetic, and at 10 minutes of recovery. Baseline ET-1 values were higher in patients with intermittent claudication as compared with control subjects (4.5 +/- 0.5 pmol/L and 2.2 +/- 0.3 pmol/L, respectively, p < 0.0001). At the end of mental stress, ET-1 levels rose significantly in both groups from baseline (p < 0.001) reaching a higher value in patients with intermittent claudication than in control subjects (5.6 +/- 0.7 pmol/L and 2.4 +/- 0.4 pmol/L, respectively, p < 0.0001). The percent increases (delta%) in ET-1 plasma concentrations from baseline in response to mental stress were significantly greater in claudicant patients than in control subjects (+23 +/- 9% and +9 +/- 7%, respectively, p < 0.0001). ET-1 plasma concentrations returned to baseline values similarly in both groups at minute 10 of the recovery period. These findings show that acute mental stress causes an exaggerated release of ET-1 in patients with intermittent claudication and suggest that this could be a potential pathophysiological mechanism through which mental stress may trigger adverse acute cardiac events and accelerate progression of atherosclerosis in these patients.

Sclerostin levels associated with inhibition of the Wnt/ß-catenin signaling and reduced bone turnover in type 2 diabetes mellitus.

CONTEXT: Patients with type 2 diabetes (T2DM) have low bone turnover, poor bone quality, and circulating levels of sclerostin significantly higher than non-T2DM controls. There are no data on the possible association of sclerostin with ß-catenin, a key component of the Wnt/ß-catenin canonical signaling. OBJECTIVES: The aim of the study was to evaluate the circulating ß-catenin levels in T2DM patients and to analyze their relationship with sclerostin and bone turnover markers. DESIGN: This was a cross-sectional study. SETTING AND PATIENTS: The study was conducted at a clinical research center. Forty T2DM postmenopausal women were studied and compared with 40 healthy controls. Bone status was assessed by dual-energy x-ray absorptiometry measurements (bone mineral density) and by measuring bone alkaline phosphatase and carboxy-terminal telopeptide of type 1 collagen. Sclerostin and ß-catenin were evaluated by an immunoenzymetric assay. RESULTS: Consistent with previous reports in T2DM subjects, we found sclerostin levels higher and bone turnover markers lower than controls. In our cohort of T2DM patients, ß-catenin levels are significantly lower than in controls (median 1.22 pg/ml, 25th to 75th percentiles 0.50-2.80; and median 4.25 pg/ml, 25th to 75th percentiles 2.20-7.62, respectively; P=0.0002). ß-Catenin correlated negatively with sclerostin (P<0.0001) and positively with bone alkaline phosphatase (P=0.0030) only in T2DM patients and negatively with age in both groups. Eight of the 40 T2DM patients had vertebral fractures. CONCLUSIONS: These results show for the first time that T2DM patients have serum concentrations of ß-catenin lower than controls. The negative association of ß-catenin with sclerostin suggests a biological effect of increased sclerostin on the Wnt signaling, which appears impaired in T2DM.

Reduction of volumetric bone mineral density in postmenopausal women with hepatitis C virus-correlated chronic liver disease: a peripheral quantitative computed tomography (pQCT) study.

BACKGROUND: The prevalence of osteoporosis in chronic liver disease (CLD) varies considerably among the studies, depending on patient selection and diagnostic criteria. We aimed to measure bone turnover markers and volumetric bone mineral density (BMD) in a group of postmenopausal women with CLD using both dual energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT), in comparison with age-matched healthy subjects. METHODS: Thirty-five postmenopausal patients with HCV-correlated CLD and 35 healthy postmenopausal women, as controls, underwent a DXA scan at lumbar and femoral level and a pQCT measurement of the nondominant forearm. Serum concentrations of biochemical markers relevant to bone turnover were also measured. RESULTS: Patients showed no differences in DXA values either at lumbar or femoral level compared to controls. On the contrary, pQCT geometrical (cortical cross-sectional area) and volumetric (total and trabecular volumetric BMD) parameters were significantly reduced in the CLD women. Also the Strength-Strain Index (SSI), an estimate of diaphyseal bone resistance to bending and torsion, was significantly lower in patients than in controls. Patients with CLD presented an unbalanced bone turnover, with increased bone resorption markers. CONCLUSIONS: The bone geometrical and volumetric parameters measured in our CLD postmenopausal women, by pQCT, show a reduced bone mineral quality and stiffness. Conversely, DXA-measurements seem unable to appreciate the bone alterations in these patients. This would encourage further studies to validate pQCT analysis as a diagnostic tool for a correct estimate of bone involvement in CLD.

An in vivo experimental study on osteopenia in diabetic rats.

Osteopenia is a significant problem associated with Diabetes mellitus. Osteopenia may result in an increased delay in healing of bone fractures and subsequently affect the quality of life. We evaluated the immunohistochemical localization of TRAIL and its receptor DR5 in the femoral bone of 10-week-old Sprague-Dawley male rats treated with sesame oil (control, group 1), streptozotocin (STZ), a diabetes inducer (group 2), L-NAME, a general inhibitor of NOS activity (group 3), L-arginine (group 4), (arginine acts as a NO substrate) and iNOS immunostaining in group 1 and group 4. Histological and histochemical findings showed decreased growth of metaphyseal cartilage (which was thinner), decreased osteoid surface, and reduced mineral apposition rate in STZ- and L-NAME-treated rats. These findings confirm that bone formation is impaired in diabetic osteopenia. L-arginine supplementation seems to prevent diabetes-induced bone alterations and preserve the calcification process, allowing synthesis of new bone matrix. The immunohistochemical study revealed increased immunostaining of TRAIL and DR5 in osteoblastic cells of the diaphysis (pre-metaphysis) and epiphysis treated with STZ and L-NAME, related to activation of osteoblastic apoptotic death, while the group receiving L-arginine was comparable to the control group and the higher indications of iNOS activity that may reflect its induction by L-arginine administration. The action of L-arginine suggests that increased NO synthesis and availability is potentially useful for effective prevention and treatment of diabetic osteopenia.

Does systematic preliminar colour Doppler study reduce kidney biopsy complication incidence?

While ultrasonography is widely performed prior to biopsy, colour Doppler examination is often used only to discover post-biopsy complications. Aim of this paper was to evaluate the usefulness of colour Doppler examination in planning the optimal site of puncture for renal biopsy. Present analysis includes 561 consecutive percutaneous renal biopsies performed from the same operator. Until August 2000 332 biopsies were performed after a preliminary ultrasonography (Group A). From September 2000, 229 patients underwent even a preliminary colour Doppler study (Group B). Postbioptic bleeding were categorized as minor (gross hematuria or subcapsular perinephric hematoma < 4 cmq of greater diameter) or major (hematoma >4 cmq of greater diameter; requiring blood transfusion or invasive procedures; leading to acute renal failure, urine tract obstruction, septicaemia, or death). Major complications were seen in 2.1% in Group A while in Group B only one case was reported (0.43%). Minor clinically significant complications occur in 7.8% in Group A and in 3.4% of cases of Group B. Colour Doppler reduced drastically the incidence of complications observed before the introduction of routine colour Doppler examination prior to biopsy. In our opinion, these data support the use of preliminary colour Doppler study when a biopsy is planned.

Vertebral morphometry by X-ray absorptiometry: which reference data for vertebral heights?

INTRODUCTION: The recent improvement in the resolution of dual-energy X-ray absorptiometry (DXA) images enables most vertebral levels to be seen adequately and thus DXA may be a worthwhile alternative to radiologic morphometry for the identification of vertebral fractures (VF). In this multicenter study, we have derived reference data for vertebral heights and their ratios in Italian women using morphometric X-ray absorptiometry (MXA). METHODS: DXA scans were acquired in 1254 consecutive pre- and postmenopausal women, (mean age 63.7 ± 11.3, range 26-88 yrs), referred to six osteoporosis centers. MXA analysis of these images was performed by the same operator measuring vertebral heights and height ratios from L4 to T4. We calculated measures of central tendency and dispersion of vertebral heights and vertebral ratios using different approaches (mean and standard deviation as well as median and interquartile range of raw data, mean and standard deviation of trimmed data using an iterative algorithm, and mean and standard deviation of not fractured vertebrae). RESULTS: Independently of the approach that we used, all the measures of central tendency were similar, while significant differences were found when compared with reference ranges in other populations. The vertebral heights of our sample at every vertebral level were significantly smaller than both Rea population and the Lunar reference values, even after normalization. Splitting data according to age groups, there was a decrease in the vertebral heights and ratios between the younger and older women. CONCLUSIONS: This study demonstrates that reference data for MXA should be population specific and age matched.

Impaired cognitive performance in asymptomatic peripheral arterial disease: relation to C-reactive protein and D-dimer levels.

BACKGROUND AND PURPOSE: asymptomatic peripheral arterial disease (APAD), a highly prevalent condition in the general older population, is associated with an increased risk of cerebrovascular events because of co-existing clinical or subclinical cerebral atherosclerosis. The purpose of this study was to investigate whether cognitive function is impaired in stroke- and transient ischaemic attack-free patients with APAD, and whether inflammatory and haemostatic markers are associated independently with neuropsychological performance. METHODS: cognitive performances of 164 well-functioning, community-dwelling patients with APAD were compared with those of 164 age-, gender- and education-matched healthy control subjects on six neuropsychological tests. Levels of C-reactive protein (CRP), D-dimer and fibrinogen were also analysed in all participants. RESULTS: patients with APAD scored significantly worse (P < 0.0001) than control subjects on five cognitive tests assessing domains of verbal working memory, attention, perceptuomotor speed, mental flexibility, visuoconstructive skills and visual memory. Multiple linear regression analyses showed that CRP and D-dimer were significant, independent predictors of poorer performances on four and three cognitive tests, respectively, within patients with APAD. CONCLUSIONS: patients with APAD show cognitive impairment in a range of psychometric tests, and CRP and D-dimer appear to be independent negative predictors of some cognitive performances. These findings suggest the need for screening for APAD among at-risk subjects in order to identify patients to be treated for prevention of functional decline and dementia. They also support the hypothesis that inflammation and hypercoagulability are implicated in the pathophysiology of cognitive dysfunction associated with APAD.

Increased prevalence of peripheral arterial disease in osteoporotic postmenopausal women.

The aim of this study was to investigate the prevalence and correlates of peripheral arterial disease (PAD) in a population of osteoporotic postmenopausal women. The presence of PAD was assessed by ankle brachial index (ABI) in 345 ambulatory osteoporotic postmenopausal women, and in 360 community-based, age- and race-matched postmenopausal women with normal bone mineral density (BMD) (control group). PAD was detected in 63/345 (18.2%) osteoporotic women and in 14/360 (3.8%) control subjects (P < 0.0001). The mean ABI values were significantly lower in the osteoporosis group than in the control group (0.98 +/- 0.09 vs. 1.04 +/- 0.06, P < 0.0001). No difference in cardiovascular risk factors was observed between osteoporotic patients and controls, or between osteoporotic patients with and without PAD. Osteoporotic patients with PAD had lower femoral neck BMD T scores than those without PAD (-4.2 +/- 0.7 vs. -2.3 +/- 0.7, P < 0.0001). Only 4 PAD patients (5.1%) had intermittent claudication. In multivariate logistic regression analysis, factors independently associated with PAD within osteoporotic patients were lower femoral neck BMD T score (odds ratio (OR) = 0.20, 95% confidence interval (CI), 0.05-0.70, P = 0.01) and systolic blood pressure (OR = 1.02, 95% CI, 1.00-1.03, P = 0.01). This study shows for the first time an increased prevalence of PAD among osteoporotic postmenopausal women, with a lower femoral neck BMD T score being a significant independent predictor. The findings suggest that vascular status evaluation should be done in osteoporotic postmenopausal women in order to identify candidate patients for preventive and therapeutic cardiovascular interventions.

Supplementation of L-arginine prevents glucocorticoid-induced reduction of bone growth and bone turnover abnormalities in a growing rat model.

The present study was designed to evaluate the effects of glucocorticoid (GC) treatment on bone turnover and bone mineral density in the growing rat. Because of the recent evidence that nitric oxide (NO) can counteract prednisolone-induced bone loss in mature rats, we examined the effect on bone of the NO donor L: -arginine in young male rats, in which bone mass is increased by the same biological mechanism as in children and adolescents. Thirty-six 10-week-old Sprague-Dawley male rats were assigned to six groups of six animals each, and treated for 4 weeks with either vehicle (once a week subcutaneous injection of 100 microl of sesame oil); prednisolone sodium succinate, 5 mg/kg, 5 days per week by intramuscular injection (i.m.); L-arginine, 10 mg/kg intraperitoneally (i.p.) once a day; N(G)-nitro-L-arginine methylester (L-NAME), 50 mg/kg subcutaneously once a day; prednisolone sodium succinate 5 mg/kg, 5 days per week i.m. +L-arginine 10 mg/kg i.p. once a day; or prednisolone sodium succinate, 5 mg/kg, 5 days per week i.m. +L-NAME 50 mg/kg subcutaneously once a day. Serum calcium, alkaline phosphatase (ALP), osteocalcin, and the C-terminal telopeptides of type I collagen (RatLaps) were measured at baseline conditions and after 2 and 4 weeks. Prior to treatment, and after 2 and 4 weeks, the whole body, vertebral, pelvic, and femoral bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DXA) scanning. Prednisolone and prednisolone+L-NAME treated rats had significantly lower ALP and osteocalcin levels than controls at 2 and 4 weeks, and significantly higher levels of Rat-Laps than controls at 4 weeks. Prednisolone, L-NAME, and prednisolone+L-NAME produced a significant inhibition of bone accumulation and bone growth at all sites measured. Supplementation with L-arginine appeared to prevent the inhibition of bone growth and increase in bone resorption induced by prednisolone. These data would suggest, for the first time, that supplementation with an NO donor could be considered as a treatment for steroid-induced osteoporosis in the developing skeleton.