Cristina Tamone

Estrogen deficiency increases osteoclastogenesis up-regulating T cells activity: A key mechanism in osteoporosis

Compelling evidences suggest that increased production of osteoclastogenic cytokines by activated T cells plays a relevant role in the bone loss induced by estrogen deficiency in the mouse. However, little information is available on the role of T cells in post-menopausal bone loss in humans. To investigate this issue we have assessed the production of cytokines involved in osteoclastogenesis (RANKL, TNFalpha and OPG), in vitro osteoclast (OC) formation in pre and post-menopausal women, the latter with or without osteoporosis. We evaluated also OC precursors in peripheral blood and the ability of peripheral blood mononuclear cells to produce TNFalpha in both basal and stimulated condition by flow cytometry in these subjects. Our data demonstrate that estrogen deficiency enhances the production of the pro-osteoclastogenetic cytokines TNFalpha and RANKL and increases the number of circulating OC precursors. Furthermore, we show that T cells and monocytes from women with osteoporosis exhibit a higher production of TNFalpha than those from the other two groups. Our findings suggest that estrogen deficiency stimulates OC formation both by increasing the production of TNFalpha and RANKL and increasing the number of OC precursors. Women with post-menopausal osteoporosis have a higher T cell activity than healthy post-menopausal subjects; T cells thus contribute to the bone loss induced by estrogen deficiency in humans as they do in the mouse.

Prevalence of Paget's disease of bone in Italy

We examined the prevalence of PDB in Italy from radiological, scintigraphic, and biochemical surveys in two Italian towns. Prevalence rates varied from 0.7% to 2.4%, were higher in males than in females, and slightly differed between the two towns. Unlike previous studies in populations of British descent, no secular trend for a decreasing prevalence emerged.

Spontaneous osteoclast formation from peripheral blood mononuclear cells in postmenopausal osteoporosis

Osteoclasts are cells involved in bone reabsorbing and hence in postmenopausal bone loss. There is no evidence of increased in vitro spontaneous osteoclast formation in postmenopausal osteoporosis. The aim of our study was to evaluate spontaneous osteoclastogenesis in osteoporosis. Bone mineral density, markers of bone turnover, and cultures of peripheral blood mononuclear cells (PBMC) on dentine slices with or without the addition of 1,25‐OH vitamin D3 ([10−8 M]) were obtained from 18 osteoporotic women and 15 controls. To verify cytokine production by PBMC cultures, supernatants were collected on days 3 and 6 and tested for TNF‐α and RANKL. The data obtained were compared between patients and controls by one‐way ANOVA and correlated by Pearsons coefficient. We found a significant increase in osteoclast formation and bone reabsorbing activity in patients with respect to controls; in addition, the production of TNF‐α and RANKL is significantly higher in patients. Furthermore, osteoclast number is inversely correlated with bone mineral density and directly with RANKL in culture supernatants. Our data demonstrated an increased spontaneous osteoclastogenesis in women affected by postmenopausal osteoporosis: this increase may be explained by the higher production of TNF‐α and RANKL by PBMC cultures of osteoporotic patients.

Risedronate reduces osteoclast precursors and cytokine production in postmenopausal osteoporotic women

This paper studies the effect of oral risedronate on osteoclast precursors, osteoclast formation, and cytokine production in 25 osteoporotic women. Risedronate is effective in reducing the number of osteoclast precursors, their formation, vitality, and activity and the level of RANKL and TNF‐α in cultures.

Role of iron metabolism and oxidative damage in postmenopausal bone loss

It has been suggested that iron-deficient rats have lower bone mass than iron-replete animals, but a clear association between bone and iron repletion has not been demonstrated in humans. A growing body of evidences also suggests a relation between lipid oxidation and bone metabolism and between iron metabolism and LDL oxidation. Iron availability to cells also depends on haptoglobin (Hp) phenotypes. Hp has also important antioxidant properties according to its phenotype, hence we evaluate whether Hp phenotype could influence bone density, iron metabolism and lipid oxidation. This cross-sectional study enrolled 455 postmenopausal women affected by osteoporosis (260) or not (195). Bone mineral density, markers of bone and iron metabolism, levels of oxidized LDL (oxLDL) and Hp phenotype were measured in all the subjects. Hp 1.1 and 2.2 frequency was higher and Hp 2.1 was lower in the patients with fragility fractures (80) compared with the controls. We therefore evaluate different Hp phenotypes as risk or protective factors against fragility fracture: Hp 2.1 is a protective factor against fracture while 1.1 is an important and 2.2 a moderate risk factor for fragility fractures. Lower serum iron was associated with elevated transferrin in patients with Hp 1.1; moreover patients had relative iron deficiency compared with the controls and fractured patients had higher level of oxLDL. We found that both iron metabolism and oxLDL varies according to Hp phenotypes and are predictive of bone density. Our data indicate that Hp 2.1 is a protective factor for fragility fractures, depending on its role on iron metabolism and its antioxidant properties.

Effects of lifestyle and risk factors on bone mineral density in a cohort of Italian women: suggestion for a new decision rule.

In this study the authors analyzed the role of risk factors in postmenopausal osteoporosis in a cohort of Italian women and evaluated predictive values of decision rules for early identification of osteoporotic women. Furthermore, the authors investigated the prevalence of secondary osteoporosis in this population. Women who underwent bone densitometry were asked to answer a questionnaire about the common risk factors for osteoporosis. Patients were classified as nonosteoporotic, nonosteopenic, and osteoporotic. Risk factors were compared among the groups by use of analysis of variance (ANOVA). National Osteoporosis Foundation (NOF) recommendation, Osteoporosis Risk Assessment Instruments (ORAIs), Osteoporosis Self-Assessment Tools (OST) score, and weight criterion were applied to this population. The authors proposed a new decision rule based on a new score. A total of 525 women received the questionnaire: 47.4% women were osteoporotic, 32.2% were osteopenic, and 20.4% nonosteoporotic. Risk factors that differed significantly between these groups were: age, age at menarche, postmenopausal period, and body mass index (BMI); the aforementioned risk factors appear to be significant predictors of bone density (BMD) in linear regression model. The incidence of secondary osteoporosis was 13%.In conclusion, the authors (1) confirmed the role played by nonmodifiable risk factors in determining BMD; (2) showed that the use of NOF guidelines, ORAI, OST score, and weight criterion is not satisfactory in our cohort; (3) suggested a new score, based upon the features that were significantly different between patients and controls; and (4) demonstrated the relatively high prevalence of secondary osteoporosis and suggest a primary screening for secondary osteoporosis in all patients with low BMD.

Teriparatide increases the maturation of circulating osteoblast precursors

SummaryThis study shows that teriparatide promotes the circulating osteoblast (OB) precursor degree of maturation in patients affected by postmenopausal osteoporosis.IntroductionAnabolic treatment with teriparatide has proven effective for the therapy of postmenopausal osteoporosis and significantly reduces the risk of non-vertebral fragility fractures. The aim of this study was to investigate the effect of teriparatide on circulating OB precursors.MethodsWe evaluated by flow cytometry and real-time PCR the expression of OBs typical markers in peripheral blood mononuclear cells during treatment with teriparatide plus calcium and vitamin D, raloxifene plus calcium and vitamin D or calcium and vitamin D alone at various time points. Serum bone alkaline phosphatase and osteocalcin (OC) were measured as markers of bone turnover.ResultsOur results show that circulating OB precursors are more numerous and more immature in patients affected by fragility fractures than in osteoporotic patients without fractures. We also show that teriparatide treatment increases the expression of alkaline phosphatase and of OC in OB precursors; thus, it increases their degree of maturation.ConclusionsWe suggest that teriparatide acts as anabolic agents also by promoting the maturation of OB precursors.

Effect of intermittent PTH treatment on plasma glucose in osteoporosis: A randomized trial☆

We investigated the effect of bone turnover on glucose homeostasis, fat distribution and adipokine production during anabolic treatment with PTH. This is a parallel, randomized controlled, open label, trial. The randomization was done by computer generated tables to allocate treatments. Forty-six postmenopausal osteoporotic non-diabetic women were assigned to treatment with calcium and colecalcipherol with (24) or without (22) PTH 1-84. Patients were recalled after 3, 6, 12 and 18 months of treatment and markers of bone turnover, glucose metabolism, adipokine secretion and fat distribution were analyzed. Markers of bone turnover and adipokines were measured by ELISA. Glucose metabolism was evaluated by an oral glucose load test and insulin resistance and secretion were calculated. Fat and lean mass were evaluated by anthropometric measures. The effect of treatment on measured variables was analyzed by repeated measure test, and its effect on glucose was also evaluated by mediation analysis after correction for possible confounders. Twenty patients in the calcium and vitamin D groups and 19 in the group treated with PTH 1-84 completed the study. There were no significance adverse events. Treatment with PTH increases osteocalcin, both total (OC) and undercarboxylated (uOC), and decreases blood glucose, without influence on insulin secretion, resistance and pancreatic β cell function. Treatment with PTH does not influence fat distribution and adipokine production. The results of the mediation analyses suggest a total effect of PTH on blood glucose, moderately mediated by OC and to a less extent by uOC. Here we suggest that treatment with PTH influences glucose metabolism partially through its effect on bone turnover, without influence on insulin secretion, resistance, pancreatic β cell function and fat mass.

Hypoparathyroidism and co-existing celiac disease

A 62-yr-old woman with idiopathic hypoparathyroidism was admitted to our hospital for severe anemia (Hb 5.6 gr/dl) and hypoalbuminemia (3.2 gr/dl). Hypoparathyroidism was diagnosed when she was 33 yr old, because of repeated hypocalcemic tetanic crises, low calcium and high phosphate levels. Since then she has been treated with oral calcium gluconate and calcitriol, with satisfactory clinical balance and normalization of calcium serum levels. After menopause, despite this therapy, the patient still had frequent hypocalcemic tetanic crises, resolving with iv administration, in high doses, of calcium gluconate. The anemia, for which the patient came to our attention, was hypochromic microcytic and in the past she had been treated with iron and transfusion therapy. The patient’s recent history also revealed recurrent long lasting episodes of diarrhea, hyporexia and weight loss. The clinical presentation seemed related to a malabsorption syndrome: a celiac disease (CD) diagnosis was confirmed, based upon the finding, at duodenal biopsy, of a severe villous atrophy. A bone mineral density (BMD) evaluation showed a limited reduction of femoral values classified as osteopenia according to the World Health Organization (WHO) criteria. Thereafter, the patient was instructed to follow a gluten-free diet which rapidly led to an improvement of the nutritional parameters and to a reduction of calcium and vitamin D requirements. Difficult clinical and metabolic control in hypoparathyroidism patients may suggest the possible co-existence of both endocrine and extra-endocrine autoimmune diseases, such as CD. Moreover, bone density, normally reduced in celiac patients, seems to be preserved (maintained) by the lack of parathyroid secretion.

Impact of a Phone Follow-Up Program on Persistence with Teriparatide or PTH(1–84) Treatment

A follow-up program to help patients suffering from severe osteoporosis during their therapy with teriparatide or PTH(1–84) has been designed and performed. The objective of this study was to evaluate the 18-month persistence on these therapies in patients participating in the program. We enrolled 382 patients who started teriparatide or PTH(1–84) following this program and compared them with a historical cohort of 398 patients treated with the same therapies but who did not participate in any follow-up program. At the beginning of the therapy, nurses trained patients on self-injection. Patients received one phone call per week during the first month, then one phone call per month and per 3xa0months during the following 5 and 12xa0months, respectively. In every call, nurses helped patients to resolve any possible issues and collected adverse event information. The persistence rate of the group following the program was 85.6%, 8.2% higher than that of the group not following any program (77.4%). The log-rank test on persistence rates on therapy in patients enrolled and not enrolled in the program was performed; the difference was statistically significant (Pxa0=xa00.006). Discontinuation in the follow-up program group occurred mainly at early stages of the treatment due to adverse events. Our results show that patients suffering from severe osteoporosis treated with teriparatide or PTH(1–84) and enrolled in a follow-up program have higher persistence rates than patients not following the program.