In vivo studies have shown T cells to be central to the mechanism by which estrogen deficiency induces bone loss, but the mechanism involved remains, in part, undefined. In vitro, T cells from ovariectomized mice produce increased amounts of tumor necrosis factor (TNF), which augments receptor activator of NF-B ligand (RANKL)-induced osteoclastogenesis. However, both the mechanism and the relevance of this phenomenon in vivo remain to be established. In this study, we found that ovariectomy increased the number of bone marrow T cell-producing TNF without altering production of TNF per T cell. Attesting to the essential contribution of TNF, ovariectomy induced rapid bone loss in wild type (wt) mice but failed to do so in TNF-deficient (TNF ؊͞؊ ) mice. Furthermore, ovariectomy induced bone loss, which was absent in T cell-deficient nude mice, was restored by adoptive transfer of wt T cells, but not by reconstitution with T cells from TNF ؊͞؊ mice. These findings demonstrate the key causal role of T cell-produced TNF in the bone loss after estrogen withdrawal. Finally, ovariectomy caused bone loss in wt mice and in mice lacking p75 TNF receptor but failed to do so in mice lacking the p55 TNF receptor. These findings demonstrate that enhanced T cell production of TNF resulting from increased bone marrow T cell number is a key mechanism by which estrogen deficiency induces bone loss in vivo. The data also demonstrate that the bone-wasting effect of TNF in vivo is mediated by the p55 TNF receptor.ovariectomy ͉ osteoporosis ͉ mouse ͉ pQCT I t is now recognized that one of the main mechanisms by which estrogen deficiency causes bone loss is by stimulating osteoclast formation (1), a process induced by the simultaneous stimulation of osteoclast precursors by macrophage colonystimulating factor (M-CSF) and a tumor necrosis factor (TNF)-related factor known as receptor activator of NF-B ligand (RANKL) (also known as OPGL, TRANCE, or ODF) (2-4).In physiologic, unstimulated conditions, the differentiation of osteoclast precursors into mature osteoclasts in the bone marrow depends on the production of M-CSF by monocytes and stromal cells and RANKL by stromal cells and osteoblasts (5). However, in stimulated conditions, additional bone marrow cells contribute to regulating osteoclast formation by producing soluble and membrane-bound pro-and antiosteoclastogenic cytokines. Among them are naïve and activated T cells, which modulate osteoclast formation trough increased production of RANKL (6-8), osteoprotegerin (9), and IFN-␥ (10).During inflammation and autoimmune arthritis, activated T cell production of RANKL promotes bone resorption and bone loss (6) whereas release of IFN-␥ limits T cell-induced bone wasting (10). Recent studies from our laboratory have disclosed that activated T cells play an essential causal role not only in inflammation-induced bone loss, but also in the bone wasting induced by estrogen deficiency (11). In fact, whereas ovariectomy (ovx) stimulated bone resorption and induced rapid bone loss in T cell-re...

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Objective: There is increasing evidence that common genetic risk factors underlie frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Recently, mutations in the sequestosome 1 (SQSTM1) gene, which encodes p62 protein, have been reported in patients with ALS. P62 is a multifunctional adapter protein mainly involved in selective autophagy, oxidative stress response, and cell signaling pathways. The purpose of our study was to evaluate the frequency of SQSTM1 mutations in a dataset of unrelated patients with FTLD or ALS, in comparison with healthy controls and patients with Paget disease of bone (PDB). Methods:Promoter region and all exons of SQSTM1 were sequenced in a large group of subjects, including patients with FTLD or ALS, healthy controls, and patients with PDB. The clinical characteristics of patients with FTLD or ALS with gene mutations were examined. Results:We identified 6 missense mutations in the coding region of SQSTM1 in patients with either FTLD or ALS, none of which were found in healthy controls or patients with PDB. In silico analysis suggested a pathogenetic role for these mutations. Furthermore, 7 novel noncoding SQSTM1 variants were found in patients with FTLD and patients with ALS, including 4 variations in the promoter region. Conclusions:

Animal studies have demonstrated lower levels of 1,25(OH)2D3 in a type 2 diabetes model compared with controls (1). Alterations in circulating vitamin D3 metabolites, such as decreased 1␣-hydroxylase activity and enhanced renal 25-hydroxylase activity, have been found in both experimental and human diabetes. These alterations in vitamin D metabolism may be associated with the deranged mineral homeostasis and skeletal morphology observed in rats and people with chronic insulin deficiency (2). Experimentally, vitamin D deficiency progressively reduces insulin secretion, and this reduction soon becomes irreversible (3). It was also shown that insulin deficiency may be associated with lower vitamin D-binding protein and 1,25(OH)2D3 serum levels in rats. These decreases are somewhat dependent on androgen concentration, but they are counteracted by estrogens (4).Several studies have demonstrated abnormalities in calcium, phosphate, and vitamin D metabolism in diabetic patients. In particular, Pietschmann et al. (5) evaluated 25(OH)D levels in type 1 and type 2 diabetic patients and found no difference in 25(OH)D levels between type 1 diabetic patients and control subjects, whereas 25(OH)D levels were significantly decreased in type 2 diabetic patients (5).We conducted an observational study in 799 ambulatory postmenopausal Italian women in order to assess the prevalence of hypovitaminosis D and dietary calcium insufficiency. In all patients, the levels of 25(OH)D3 (obtained by radioimmunoassay method with double antibody provided by DiaSorin), calcium intake (obtained by a questionnaire filled in by a general practitioner), and several Activity Daily Living (ADL) criteria were assessed. The samples were collected in February and March 2000.We identified 66 type 2 diabetic patients based on medical history. Female patients and control subjects were comparable for age and years since menopause, but BMI was significantly higher in diabetic patients. The ADL score was significantly worse in diabetic patients than in control subjects (P Ͻ 0.01). The 25(OH)D levels (means Ϯ SD) were significantly lower in diabetic patients than in control subjects (11 Ϯ 9.8 vs. 9 Ϯ 11.3 ng/ml, P Ͻ 0.008), and the prevalence of 25(OH) deficiency (Ͻ5 ng/ml) was significantly higher in diabetic patients than in control subjects (39 vs. 25%). Dietary calcium intake was significantly lower in diabetic patients than in control subjects (792.9 Ϯ 400.9 vs. 679 Ϯ 316.9 mg/day, P Ͻ 0.020). The significance of these findings remains unclear. The general recommendation for overweight diabetic patients to lower fat dairy product consumption may explain the lower calcium intake. We have no data that might explain the higher prevalence of hypovitaminosis D among diabetic patients. We believe our results will lead to additional studies on the hypothetical circular relationship among diabetes, vitamin D repletion, and calcium intake and absorption. We believe this relationship leads to both a worsening of diabetes and an increased risk of fractures (6), d...

In order to evaluate the prevalence, risk factors, and clinical consequences of hypovitaminosis D in elderly Italian women a multicenter study of 43 osteoporosis centers from all regions of Italy was carried out. Study population included 700 women aged 60-80 years in whom blood was taken for 25-hydroxyvitamin D (25OHD) and parathyroid hormone (PTH) measurements. All subjects were also questioned to assess the prevalence of several risk factors for hypovitaminosis D, osteoporotic fractures and activities of daily living (ADL). Values of 25OHD lower than 5 ng/ml were found in 27% of the women and lower than 12 ng/ml in 76%. 25OHD and PTH levels were negatively correlated ( r=-0.38, after logarithmic transformation of both variables). 25OHD levels significantly declined with advancing age and number of pregnancies and were positively correlated with educational level (years spent at school), dairy calcium intake, and days spent on holiday by the sea. In a multivariate model including all these variables, the only one that remained significant was the level of education. The lowest age-adjusted 25OH D levels were found in smokers or in women living in central Italy as compared with those living in northern or southern Italy. The mean (+/-SD) age-adjusted 25OH D values were significantly lower in women who sustained a hip fracture (7.1+/-2.2 versus 11.0+/-9.9). Women with low 25OHD levels (<12 ng/ml) had worse scores for ADL and mobility ADL (move outdoors, use stairs, walk at least 400 m, carry a heavy object). Vitamin D deficiency is extremely common among elderly Italian women. Women with lower educational level, living in central Italy, smokers or with lower intake of dairy products are at greater risk. Hypovitaminosis D is associated with worsening of the ability to perform activities of daily living and higher hip fracture prevalence. This finding should lead to an urgent population-based strategy to remedy this condition.