Carmelo Erio Fiore

Increased sclerostin serum levels associated with bone formation and resorption markers in patients with immobilization-induced bone loss.

CONTEXT Sclerostin, a Wnt signaling antagonist on the osteoblasts produced by osteocytes, is regulated by mechanical strain and is implicated in the pathogenesis of disuse bone loss. There are no data on sclerostin in humans. OBJECTIVE The aim of the study was to evaluate sclerostin in patients immobilized after stroke, compared with control subjects, and to analyze its relationship with markers of bone formation and resorption. DESIGN This was a cross-sectional study. SETTING AND PATIENTS We studied 40 postmenopausal women immobilized after a single episode of stroke 6 months or longer after onset, and 40 postmenopausal women from the general community. Bone status was assessed by quantitative ultrasound measurements at the calcaneus. Bone alkaline phosphatase (b-AP), carboxy-terminal telopeptide of type I collagen (CrossLaps), and sclerostin were evaluated by ELISA. We also used ELISA to measure serum levels of Dickkopf-1, another soluble inhibitor of Wnt/beta-catenin signaling, highly expressed by osteocytes. RESULTS Immobilized patients had higher sclerostin serum levels (median 0.975 ng/ml; 25th to 75th percentiles 0.662-1.490) than controls (median 0.300 ng/ml; 25th to 75th percentiles 0.165-0.400: P < 0.0001) and an increased bone turnover with a more significant rise in bone resorption (CrossLaps) than formation (b-AP) markers. Sclerostin correlated negatively with b-AP (r = -0.911; P < 0.0001) and positively with CrossLaps (r = 0.391; P = 0.012). Dickkopf-1 did not significantly differ between the groups. Patients also had quantitative ultrasound measurements index lower than controls (P < 0.001). CONCLUSIONS This study shows for the first time that long-term immobilized patients present hypersclerostinemia associated with reduced bone formation, and suggests that sclerostin could be a link between mechanical unloading and disuse osteoporosis in humans.

Strontium ranelate reduces the risk of vertebral and nonvertebral fractures in women eighty years of age and older

Strontium ranelate produces an early and sustained reduction of both vertebral and nonvertebral fractures in patients ≥80 years of age.

Sclerostin levels associated with inhibition of the Wnt/β-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 β-catenin, a key component of the Wnt/β-catenin canonical signaling. OBJECTIVES The aim of the study was to evaluate the circulating β-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 β-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, β-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). β-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 β-catenin lower than controls. The negative association of β-catenin with sclerostin suggests a biological effect of increased sclerostin on the Wnt signaling, which appears impaired in T2DM.

Renin–angiotensin system blockade is effective in reducing proteinuria of patients with progressive nephropathy caused by MYH9 mutations (Fechtner–Epstein syndrome)

Fetchner syndrome (FTNS, OMIM 153640) is an autosomal dominant disorder characterized by the association of macrothrombocytopaenia, leukocyte inclusions, sensorineural deafness, cataracts and nephropathy often leading to end-stage renal disease (ESRD) [1]. Epstein syndrome (EPTS, OMIM 153650) presents the same features of FTNS, with the exception of leukocyte inclusions and cataracts [2]. Recently, it was shown that both FTNS and EPTS derive from mutations of MYH9, the gene for the heavy chain of non-muscle myosin IIA [3,4]. The same gene was found to be also responsible for two non-syndromic forms of inherited macrothrombocytopaenia with leukocyte inclusions, May-Hegglin anomaly (MHA, OMIM 155100) and Sebastian syndrome (SBS, OMIM 605249) [3]. Further studies demonstrated that patients initially diagnosed as having MHA/SBS can subsequently develop nephropathy, deafness and/or cataracts, while affected relatives of FTNS or EPTS patients present for all their lifetime a clinical picture indistinguishable from that of MHA/SBS subjects [5]. Moreover, immunofluorescence studies showed that leukocyte inclusions containing the MYH9 protein are present not only in MHA/SBS and FTNS, but also in all patients with EPTS [5]. Therefore, it was clear that FTNS, EPTS, MHA and SBS are not distinct entities, but rather they represent different clinical presentations of a single disease, characterized by the constant finding of congenital thrombocytopaenia and leukocyte inclusions, and possible development of nephropathy, deafness and/or cataracts in

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.

L-arginine prevents bone loss and bone collagen breakdown in cyclosporin A-treated rats.

Cyclosporin A is implicated in the pathogenesis of post-transplantation bone disease. Because of recent evidence that cyclosporin A may cause renal and cardiovascular toxicity by inhibiting nitric oxide (NO) activity, and that NO slows bone remodeling and bone loss in animal and human studies, we investigated a possible link between NO production and beneficial effects on bone health in cyclosporin A-treated rats. Thirty-six 10-week-old male rats were assigned to six groups of six animals each, and treated for 4 weeks with: vehicle; cyclosporin A; L-arginine; N(G)-nitro-L-arginine methylester (L-NAME, a general inhibitor of NO synthase activity); a combination of cyclosporin A+L-arginine; and a combination of cyclosporin A+L-NAME. Whole body and regional (spine and pelvis) bone mineral content of rats were measured under basal conditions and at the end of the treatment period by dual-energy X-ray absorptiometry (DXA) scanning. Femur weights and serum concentrations of pyridinoline, a reliable marker of bone resorption, were measured at the end of the study period. Cyclosporin A-, L-NAME-, and cyclosporin A+L-NAME-treated rats had significantly lower bone mineral content and femur weights, and significantly higher pyridinoline levels than did control animals. The administration of L-arginine appeared to prevent bone loss caused by cyclosporin A, suggesting that this amino acid, which can be converted to produce NO, might prove useful in preventing disturbed bone modeling and inhibition of bone growth associated with cyclosporin A therapy.

Anti-inflammatory activity of amylin and CGRP in different experimental models of inflammation

The anti-inflammatory activity of amylin was studied in different models of inflammation, and compared to that of CGRP. Both peptides were active against mouse ear oedema induced by croton oil and acetic acid-induced peritonitis in the rat. CGRP was more potent than amylin in both models. Pretreatment with CGRP 8-37 fragment blocked the anti-inflammatory activity of both peptides in croton oil ear oedema. No anti-inflammatory activity was evidenced against serotonin-induced rat paw oedema and plasma protein extravasation induced by dextran in rat skin. Our results suggest that amylin exerts anti-inflammatory activity only in inflammatory models characterized by a vascular component. This effect appears to be mediated by the involvement of CGRP receptors.

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.

Bone ultrasonometry, bone density, and turnover markers in type 1 Gaucher disease

Abstract. In 12 patients (mean age, 33 ± 13 years) with type 1 Gaucher disease (GD), we evaluated bone mass by broadband ultrasound attenuation (BUA) of the calcaneus and dual X-ray absorptiometry (DXA) of the total body, lumbar spine, and hip. In all patients, we measured serum levels of osteocalcin (OC) and bone-specific alkaline phosphatase (BAP) and urinary excretion of pyridinoline (Pyr/Cr) and deoxypyridinoline (D-Pyr/Cr) cross-links. Compared to age- and sex-matched healthy controls, patients with GD showed marked osteopenia at all measuring sites as expected. Values of BUA (67.25 ± 15.83 dB/MHz) were also significantly reduced. OC and BAP concentrations were within the normal range. Pyr/Cr and D-Pyr/Cr were significantly higher than in controls. Calculating T- and Z scores, we found a significant correlation between the Bone Severity Score Index (BSSI) and both BUA and BMD measurements. A significant correlation was also found between pyridinoline urinary excretion and both BSSI and BUA at the calcaneus. Our data suggest that type 1 GD in adulthood is associated with increased bone resorption and that BUA at the calcaneus may be a relevant tool in the assessment of bone status in these patients.

Quantitative ultrasound of bone and clodronate effects in thalassemia-induced osteoporosis

Osteoporosis in Β-thalassemia major has emerged as a topic of interest since optimized transfusion regimens have increased life expectancy and quality in these patients. Although the pathogenesis of thalassemic osteopathy is multifactorial, the evidence of an increased resorption phase suggests that the use of antiresorptive drugs such as bisphosphonates can be considered a valuable therapeutic strategy to reduce bone turnover and the risk of fragility fractures. We compared the effects of long-term cyclical clodronate therapy (300 mg intravenous infusion every 3 weeks for 2 years) and of an active placebo (calcium 1 vitamin D) on bone mass and bone turnover in 30 male patients with Β-thalassemia major. We also tested the possibility of using quantitative ultrasound (QUS) for assessing bone involvement in thalassemic osteopenia and in monitoring the response to antiresorptive therapy. Broadband ultrasound attenuation (BUA) was significantly reduced in patients with Β-thalassemia major as compared to healthy controls. In calcium and vitamin D-treated patients, a significant decline in spine, femoral, and total body areal bone density was observed. In the patients given intravenous clodronate we measured a substantial stability of bone mass, which was not significantly changed at the end of the study. The urinary excretion of deoxypyridinoline (a marker of bone resorption) showed a progressive significant decline throughout the study period in clodronate-treated patients. No significant change was observed in BUA values in both groups of patients. These results indicate that intermittent intravenous clodronate administration was not able to increase areal bone density in our thalassemic patients. Moreover, this is the first study to have assessed the usefulness of broadband ultrasound measurements in Β-thalassemia major.