Skeletal effects of estrogens.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
M L Brandi
Publications and source records attributed to M L Brandi.
Fluid shear stress increases interleukin-11 expression in human osteoblast-like cells: its role in osteoclast induction.
It is unclear how mechanical stress influences bone cells. Mechanical stress causes fluid shear stress (FSS) in the bone. Osteoblast lineage cells are thought to sense FSS and regulate bone remodeling. We therefore investigated the effects of FSS on human osteoblast-like osteosarcoma cells: SaOS-2 cells in vitro. The conditioned medium of the SaOS-2 cells after 24 h of FSS (24 h-FSS CM) showed such osteoclastic phenotype inductions as significantly increasing the number of tartrate-resistant acid phosphatase (TRAP) positive multinuclear cells in rat bone marrow cells and TRAP-positive cells in human preosteoclastic cells: FLG 29.1 cells. An enzyme-linked immunosorbent assay showed interleukin-11 (IL-11) protein to increase 7-fold in the 24 h-FSS CM. A Northern analysis showed that IL-11 mRNA increased 4-fold in the SaOS-2 cells after 6 h-FSS; however, no IL-6 mRNA expression was detected. Furthermore, the anti-human IL-11 antibody significantly neutralized the osteoclastic phenotype induction of the 24 h-FSS CM. The IL-11 mRNA up-regulation in SaOS-2 cells by the 6 h-FSS was not inhibited by the anti-human transforming growth factor-beta1 antibody, but it was significantly inhibited by indomethacin. An enzymeimmunoassay showed prostaglandin E2 to increase 7-fold in the 1 h-FSS CM. These findings thus suggest that FSS induces osteoblasts to produce IL-11 (mediated by prostaglandins) and thus stimulates bone remodeling.
Acid Phosphatase↗
FokI polymorphism at translation initiation site of the vitamin D receptor gene predicts bone mineral density and vertebral fractures in postmenopausal Italian women.
A novel T/C polymorphism (ATG to ACG) at the translation initiation site of the vitamin D receptor (VDR) gene, defined by FokI restriction endonuclease, has been recently associated with variation in bone mineral density (BMD) and rates of bone loss in a group of postmenopausal Mexican-American women. The presence of the restriction site, designated as f, allows protein translation to initiate from the first ATG, while the allele lacking the site, indicated as F, initiates translation at a second ATG. In this study, we investigated the role of FokI polymorphism in a group of 400 postmenopausal women of Italian descent stratified for BMD into osteoporotic (n = 164), osteopenic (n = 117), and normal (n = 119) groups. There were 159 (41%) FF homozygotes, 55 (14%) ff homozygotes, and 186 (45%) Ff heterozygotes. In the whole population, we observed a weak association between FokI polymorphism and lumbar BMD (p = 0.06, analysis of covariance [ANCOVA]) but not with femoral neck BMD (p = 0.5, ANCOVA). Interestingly, the effect of FokI genotypes on lumbar BMD was influenced by the years since menopause such that differences in BMD related to different VDR allelic variants were greater among women in the first 5 years of menopause (p = 0.04, ANCOVA), progressively declining afterward. In addition, a significantly higher prevalence of ff genotype in osteoporotic than in osteopenic and normal women was observed (p = 0.04, Chi-square test). Finally, ff genotype resulted significantly over-represented in the group of women with a vertebral fracture as compared with controls (p = 0.003, Chi-square test), equivalent to a relative risk of 2.58 (95% confidence intervals 1.36-4.91). We conclude that in this population, FokI polymorphism at the VDR gene locus accounts for a part of the heritable component of BMD at the lumbar spine.
Aged↗
Apoptosis induced by sulindac sulfide in epithelial and mesenchymal cells from human abdominal neoplasms.
We investigated whether the therapeutic action of sulindac, used for the treatment of familial adenomatous polyposis, desmoid tumors, and against colon cancer, could be mediated by its active metabolite, sulindac sulfide, in cell growth and apoptosis on cell lines derived from abdominal neoplasms. Sulindac sulfide actions on cell growth and apoptosis were evaluated in epithelial human colon tumor 8 (HCT8) cell line and mesenchymal cell lines (bovine bone endothelial (BBE) cell line, desmoid tumor-derived cells, human colorectal cancer-derived fibroblasts). Sulindac sulfide (0.1-60 microg/ml) induced a dose-dependent inhibition of cell proliferation of all cell lines tested. Apoptosis was induced at doses of 20 and 40 microg/ml, respectively, in BBE and HCT8 cells with no effect on desmoid tumor cells and colorectal cancer-derived fibroblasts. Since mesenchymal cells respond to clinically effective concentrations of the compound, its preferential action on the stromal compartment of intestinal polyps, desmoid tumors and colon cancer can be proposed, with consequent regression of the tumor.
Abdominal Neoplasms↗
[Multiple endocrine neoplasia associated with multiple lipomas].
BACKGROUND: Multiple endocrine neoplasia type 1 (MEN-1) is characterized by tumors of the parathyroids, the neuroendocrine pancreas-duodenum and the anterior pituitary, but shows also a wide clinical variety of other symptoms. CASE REPORT: We present a case of a 68-year-old woman with a 18 year history of MEN-1 consisting of gastrinoma and primary hyperparathyroidism. Beside these typical symptoms, the patient suffered from thyroid adenoma, malignant kidney tumor and multiple subcutaneous lipomas. RESULT: While the number of autopsies declined from 113 in 1977 to 66 in 1984, the number of diagnostic techniques used increased continuously (94, 107, 118 and 140, amounting to 0.83, 1.34, 1.76 and 2.12 per patient). The premortal detection of abdominal abnormalities increased globally from 16.8 to 32.5%. This increase was largely due to better diagnosis of liver and gallbladder abnormalities which were in most cases of little relevance. CONCLUSION: Whether these non-endocrine tumors are associated to MEN-1 is unclear and has to be tested by examining the chromosomal regions 11q13 and 11q24/25 of the tumors sample, in which the possible MEN-1 involved tumor suppressor genes are located.
Aged↗
Polymorphisms of the calcitonin receptor gene are associated with bone mineral density in postmenopausal Italian women.
Recognition of a major genetic component in bone mass determination represented the basis for studies aiming to the identification of underlying major and minor genes. Bone mineral density (BMD) represents the continuous trait to be quantified in order to evaluate segregation of candidate genes with risk of osteoporosis. Polymorphisms at the vitamin D receptor (VDR), estrogen receptor, (ER), collagen type I, and interleukin 6 (IL6) gene loci have been correlated to BMD. However, in a polygenic disorder, such as osteoporosis, the number of genes expected to influence BMD is very large. In the present study we examined the presence of restriction fragment length polymorphisms (RFLPs) for the calcitonin receptor (CTR) gene in postmenopausal women. We identified a polymorphic (Tt) site at the CTR gene locus using the Taq I restriction fragment enzyme. Three genotypes were observed, whose Tt was the most frequent in our population (49.7%). In addition, Ancova analysis and Tukey's test showed that women with tt genotype had significantly lower lumbar BMD in comparison with Tt genotype (Tukey's test: p = 0.005). In conclusion, evidence of RFLPs at the CTR gene locus in Caucasian postmenopausal women of Italian origin made it possible to identify the involvement of another gene, the CTR gene, in the determination of bone mass.
Aged↗
Allelic variants of human calcitonin receptor: distribution and association with bone mass in postmenopausal Italian women.
Bone mass could be under control of several polymorphic genes which can modulate bone turnover via reciprocal interactions. One of the genes that can be involved in this process is the calcitonin receptor (CTR) gene. Evidence from cDNA cloning has shown that CTRs have seven potential transmembrane domains and they are known to be expressed in several tissues. In a Japanese population was discovered a novel Restriction Fragment Length Polymorphism (RFLP) at the CTR gene by Alu I restriction enzyme at the 1377th nucleotide expressing either proline (CC genotype) or leucine (TT genotype) as the 463rd amino acid. The heterozygote genotypes were indicated as TC. In the present study we analyzed the presence of this CTR gene RFLP in 307 postmenopausal Italian women. We observed that TC and TT genotypes represented the most frequent CTR genotypes in Italian women. In addition, Duncan's test used to compare the genotypes showed that TT genotype has significant lower lumbar BMD in comparison with CC genotype.
Alleles↗
Nitric oxide superoxide and peroxynitrite modulate osteoclast activity.
The gas radical, nitric oxide (NO), is a key signalling molecule in the cardiovascular, nervous and immune systems. Recently it has been found that it is produced by both the osteoblast and osteoclast and that it has major effects in producing osteoclast detachment and exerting a tonic inhibition of bone resorption. This detaching effect is mediated by a rapid increase in cGMP following calcium-triggered e-NOS activation during normal bone resorption. This effect is not reproduced in vitro by 8-bromo-cGMP but is seen with the newer rapidly permeant 8-pCPT-cGMP. However the inhibition of bone resorption by SIN-1 in vitro is not mediated solely by cGMP but depends on other factors still unidentified. Superoxide anions alone produces both osteoclast detachment and inhibition of resorption. Both of these actions may be mediated at least in part by peroxynitrite which has the same effect as NO alone on osteoclast detachment.
Animals↗
Expression of transforming growth factor beta isoforms in osteosarcoma variants: association of TGF beta 1 with high-grade osteosarcomas.
Studies on osteosarcoma cell lines point to the potential importance of transforming growth factor beta (TGF beta) as an autocrine factor which controls the growth of human osteosarcomas. To define further the role of TGF beta isoforms in these neoplasms, a series of 27 osteosarcomas was studied using immunohistochemical, mRNA in situ hybridization, and reverse transcriptase-polymerase chain reaction (RT-PCR) techniques. All 14 central high-grade osteosarcomas, two telangiectatic osteosarcomas, and one high-grade surface osteosarcoma showed cytoplasmic immunoreactivity for TGF beta 1, -2, and -3. The expression of TGF beta 1 was moderate or diffuse in 14 cases (82.3 per cent), while low expression was detected in only three cases (17.7 per cent). For TGF beta 2 and -3, only moderate or diffuse staining was observed. Low-grade parosteal and periosteal osteosarcomas showed low or undetectable levels of TGF beta 1, while TGF beta 2 and -3 were moderately or diffusely expressed. Finally, three dedifferentiated parosteal osteosarcomas were diffusely positive for TGF beta 1, -2, and -3 in the high-grade component, while in the low-grade component, available for analysis in two of these cases, TGF beta 1 was demonstrated in a few neoplastic cells, and TGF beta 2 and -3 maintained a diffuse distribution. Statistical analysis of these data showed that high-grade osteosarcomas had a significantly higher expression of TGF beta 1 than low-grade osteosarcomas, while levels of TGF beta 2 and -3 were comparable in the two groups (p < 0.001; p = 0.3; p = 0.3, respectively; Fisher's exact test). Similarly, mRNA levels of TGF beta 1 detected by in situ hybridization were significantly higher (p = 0.04, Fisher's exact test) in high-grade osteosarcoma variants, while no differences were found for TGF beta 2 and -3 mRNA (p = 1.0; p = 0.2, respectively; Fisher's exact test). In addition, mRNA analysis performed by RT-PCR in seven cases (five high-grade and two low-grade osteosarcomas) confirmed the presence of high levels of TGF beta 1 in high-grade osteosarcomas, while low-grade tumours had low or absent mRNA expression. In conclusion, this positive association suggests that TGF beta 1 may be involved in determining the aggressive clinical behaviour of high-grade osteosarcomas.
Bone Neoplasms↗
Expression of the alpha- and beta-subunits of human chorionic gonadotropin by subsets of parathyroid cells in states of hyperparathyroidism.
The alpha-subunit of human chorionic gonadotropin (hCG-alpha) has previously been found to be expressed in hyperplasias and tumours of numerous endocrine tissues including all those involved in MEN-I syndrome except the parathyroid glands. In the present immunohistochemical investigation of 86 patients with various states of hyperparathyroidism, expression of hCG-alpha by subsets of parathyroid cells was shown in 46 cases (54 per cent) including all states of hyperparathyroidism investigated: primary adenoma (n = 34, 44 per cent); uraemic secondary hyperplasia (n = 34, 53 per cent); MEN-I (n = 13, 77 per cent); MEN-II (n = 2, 100 per cent); and parathyroid carcinoma (n = 3, 100 per cent). Although the number of parathyroid cells expressing hCG-alpha was in general low, the occurrence of numerous immunoreactive cells appeared to be concentrated in primary adenoma and MEN-I (20 and 33 per cent of positive cases, respectively). No expression was found in ten normal control glands, except for very rare cells in one case. Expression of hCG-alpha was in part associated with that of hCG-beta, which appeared to be more commonly expressed than hCG-alpha in cases of secondary hyperparathyroidism. In separate experiments, Bouin fixation was found to preserve the immunoreactivity of hCG-alpha and hCG-beta better than the formalin fixation used in this study, suggesting that the figures may be underestimates. These immunohistochemical results are in agreement with a previous biochemical study showing hCG-alpha and hCG-beta in extracts of parathyroid tumours and extend to the parathyroid glands the otherwise ubiquitous finding of hCG-alpha expression in MEN-I-related neoplasms.
Adenoma↗
Effects of ipriflavone on perialveolar bone formation.
The effect of ipriflavone (IP), a synthetic isoflavonoid derivative, on in vivo bone formation was studied in rat perialveolar bone by surgically producing a hole in the mandibular bone. The holes were filled either with powdered IP or with compounds containing no osteoinductive properties such as biostite and Htr (hard tissue replacement). In control animals, the holes were left to heal spontaneously. The animals were killed 3, 28, and 40 days after surgery and a detailed morphological and morphometric study was performed on the perialveolar bone surrounding the wounds. Three days after surgery (inflammatory phase) the bone wounds were occupied by hemorragic and inflammatory cells in both the untreated and IP-treated bone defects. Twenty-eight days after surgery, bone formation was evident with new bone spiculae particularly concentrated in the area of the bone lesion closest to the adjacent periodontal ligament. Morphometric measurements of the areas occupied by new bone showed that the synthesis of perialveolar bone was significantly stimulated by IP. The repair of the bone defects by new bone formation progressed by day 40, but only in the presence of IP were the original holes almost completely repaired. Conversely, biostite and Htr did not influence promotion of new bone formation. In conclusion, the results of the present study are consistent with a role of IP in stimulating osteogenesis and suggest that this compound could represent a potential therapeutic tool to promote repair of injured perialveolar bone.
Alveolar Process↗
Ductal adenocarcinoma of the pancreas in MEN-1-patients.
Explore the source record for details and available documents.
Adenocarcinoma↗
Aromatase expression and activity in the human leukaemic cell line FLG 29.1.
The recent observation that estrogen synthesis occurs in osteoblast-like cells has suggested the aromatase activity as a possible local modulator of bone remodeling in post-menopausal women. To provide further insights into the androstenedione conversion to estrogen in bone-derived cells, we examined the human leukaemic cell line FLG 29.1, which is induced to differentiate toward the osteoclastic phenotype by TPA and TGF-beta1. Southern blot of RT-PCR products with a 32P-labeled cDNA probe for the human aromatase demonstrated that FLG 29.1 cells express aromatase mRNA. The enzyme activity, determined by measuring [3H]H2O release from [3H]androstenedione, obeyed Michaelis-Menten kinetic with apparent Km and Vmax values ranging from 5 to 10 nM and from 200 to 400 fmol/mg protein/6 h. Gene expression, enzyme activity and protein immunoreactivity, evaluated by immunocytochemistry, were stimulated in a time-dependent fashion by 5% charcoal-stripped FCS and by either 1-100 nM TPA or 0.01-0.5 ng/ml TGF-beta1, with maximal responses after 2-3 h exposure. After 24 h incubation of FLG 29.1 cells in the absence of these stimuli the aromatase mRNA and the protein were barely detectable. These findings demonstrate that cells of the osteoclastic lineage synthesize estrogen in vitro and that local cytokines, such as TGF-beta1, are able to induce androstenedione conversion.
Androstenedione↗
Vitamin D and estrogen receptor allelic variants in Italian postmenopausal women: evidence of multiple gene contribution to bone mineral density.
Bone mass and bone turnover are under genetic control. Restriction fragment length polymorphisms (RFLPs) at the vitamin D receptor (VDR) gene locus have been recently correlated to bone mineral density (BMD) and rate of bone loss. However, agreement on this relationship is not universal. The existence of ethnical and environmental differences between populations, a health-based selection bias in several previous studies, and the involvement of other genes could explain these discordant findings. In this study, we examined the relationship of VDR and estrogen receptor (ER) gene RFLPs with lumbar spine and upper femur BMD in 426 Italian postmenopausal women, 57.7 +/- 0.4 yr old (144 normal, 106 osteopenic, and 176 osteoporotic). VDR gene RFLPs for ApaI, Bsm I, and TaqI restriction endonucleases and ER RFLPs for PvuII and XbaI restriction endonucleases were assessed by Southern blotting analysis and were indicated, respectively, as A-a, B-b, T-t, P-p, and X-x (uppercase letters signifying the absence and lowercase letters the presence of the restriction site). After correcting for potential confounding factors (age, height, weight, age since menopause, osteophytosis, and facet joint osteoarthritis), a statistically significant VDR genotype effect on lumbar BMD (P = 0.01, analysis of covariance), but not on femoral BMD, was detected, with subjects in AABBtt genotype showing a 13% lower BMD than those with aabbTT genotype (P < 0.05, Tukey's test). Moreover, a statistically significant prevalence of AABBtt genotype in osteoporotics, and of AabbTT and aabbTT genotypes in nonosteoporotics, were detected. Conversely, there was no significant relationship of ER genotype to either lumbar or femoral BMD, even though a trend for higher BMD values in women with the ER PP genotype (with respect to those with ER pp genotype) was detected. When mean lumbar BMD was calculated for women grouped by ER and VDR genotype, we observed a significant difference between those within the 2 opposite associations AABBtt-PPXX and aabbTT-ppxx (0.71 +/- 0.05 vs. 0.97 +/- 0.03 g/cm2, P < 0.05 Tukey's test). These results are consistent with a segregation of the VDR AABBtt genotype with a higher risk of developing osteoporosis, in the Italian female population. The introduction of another variable, the ER genotype, in the analysis of VDR genetic determination of BMD, may represent a useful model in the identification of patients at risk of developing a multigenic disorder like osteoporosis.
Alleles↗
Expression of Src family kinases and their putative substrates in the human preosteoclastic cell line FLG 29.1.
Several lines of evidence suggest that the c-Src tyrosine kinase has a specific role in bone-resorbing osteoclasts. To investigate this further, we examined the expression of c-Src, its kinase family members, and their putative substrates in the human leukemia cell line FLG 29.1. Western blot analysis with specific antibodies against Src family members showed expression of Src, Fyn, and Lyn, lower levels of Yes and Hck, and the absence of Lck tyrosine kinase. During a 3-day treatment with phorbol 12-myristate, 13-acetate (PMA), which induces differentiation of FLG 29.1 cells toward an osteoclast-like phenotype, the levels of Src and Fyn increased and the levels of Lyn decreased. In a similar leukemia cell line, HL-60, Src protein was not constitutively expressed and not induced by PMA treatment, which leads to monocytic differentiation. PMA treatment of FLG 29.1 cells induced a strong increase in the expression of p120 Cbl and Pyk2 kinase, which are putative Src substrates. Pyk2 phosphorylation increased upon adherence of FLG 29.1 cells to fibronectin and to ST2 stromal cells. The expression of other Src substrates and interacting proteins, such as p120 Cas, p130 Cas, vinculin, Fak kinase, and the p85 phosphatidylinositol 3-kinase subunit either did not change or slightly increased during PMA treatment. The elevated total protein tyrosine phosphorylation in PMA-treated FLG 29.1 cells was abolished by herbimycin A, a Src inhibitor. These data are consistent with the proposed role of Src in the osteoclastic function and support the use of FLG 29.1 cells as a model to study Src substrates in the cells of the osteoclastic lineage.
Blotting, Western↗
Heterogeneity of binding sites and bioeffects of raloxifene on the human leukemic cell line FLG 29.1.
The benzothiophene divarative raloxifene is known to mimic estrogen in human bone remodeling. To investigate the "in vitro" properties of raloxifene on osteoclast precursors, the human leukemic cell line FLG 29.1, which differentiates toward the osteoclastic phenotype, was examined for raloxifene binding and for evidence of its bioeffects. Scatchard and Hill analysis of binding data with the tritiated raloxifene demonstrated the presence of two classes of binding sites in both nuclear and cytosol fractions with Kd values of approximately 1 nM and approximately 5 nM, respectively. In addition, analysis of binding data using tritiated 17 beta E2 as ligand at high concentrations (10-40 nM) and either unlabeled 17 beta E2 or raloxifene as competitors gave similar results demonstrating the presence of type II EBS in these cells. Picomolar concentrations of raloxifene significantly (p < 0.05) inhibited cell proliferation. Moreover, the compound at nanomolar concentrations induced a significant dose- and time-dependent increase of progesterone receptor, and activated apoptotic cell death. These findings clearly demonstrate that raloxifene acts as an estrogen agonist in FLG 29.1 cells, acting through the estrogen receptor and, possibly, via multiple cooperative binding component(s).
Apoptosis↗
Bone mineral metabolism in diet-induced amenorrhea.
Spinal bone density of 41 girls with diet-induced amenorrhea (DA) was compared with that of the density of 22 subjects with premature ovarian failure (POF) of comparable age. The Z score values, as well as the estradiol levels, were not significantly different in the two groups. The duration of amenorrhea was significantly correlated to bone mass density in the DA population, especially when considering subjects with amenorrhea that had lasted longer than 20 months. A similar correlation between weight loss and BMD was evident. Although estradiol concentrations did not seem to be correlated to the Z score, FT3 and cortisol values exhibited, respectively, a negative and a positive correlation with spinal density. Cortisol seemed to act precociously, whereas FT3 acted later than cortisol.
Adolescent↗
A human homolog of the 150 kD avian osteoclast membrane antigen related to superoxide dismutase and essential for bone resorption is induced by developmental agents and opposed by estrogen in FLG 29.1 cells.
Osteoclast development from hematopoietic bone marrow precursors is associated with the expression of various enzymes, receptors, adhesion molecules, and other specialized components. Among these is a novel 150 kD superoxide dismutase-related membrane glycoprotein, originally identified by its reaction with the anti-osteoclast monoclonal antibody 121F. This antigen is uniquely restricted to osteoclasts in bone, universally present on osteoclasts from multiple species, induced during osteoclast differentiation in vitro and in ovo, and required at high levels for avian osteoclastic bone pit resorption. Expression of a comparable human antigen was investigated using human leukemic FLG 29.1 cells capable of differentiating towards an osteoclast-like phenotype. Phorbol ester, 1,25 (OH)2 vitamin D3, and osteoblast-derived soluble factors elicited dose and time-dependent inductions of this antigen as measured by enzyme-linked immunosorbent assay (ELISA) and immunocytochemical staining, coincident with their display of multiple other osteoclastic features. Synergistic interactions of these modulators led to further elevations in the ultimate expression levels of this antigen, although not to the full extent associated with in vivo-formed avian osteoclasts. The potent antiresorptive hormone 17beta-estradiol, but not its inactive alpha isomer, partially suppressed the phorbol ester-induced elevation of the 121F antibody-reactive antigen in FLG 29.1 cells as it does in avian osteoclast-like cells. Characterization of the human antigen isolated from FLG 29.1 cells by 121F immunoaffinity purification demonstrated that this regulated membrane component was synthesized by these human cells, more abundant following their differentiation into osteoclast-like cells, and similar biochemically and immunologically to the 150 kD integral membrane glycoprotein previously described from avian osteoclasts. Therefore, this report is the first documentation that human osteoclast-like FLG 29.1 cells express, in a developmentally regulated fashion, a homolog of the specific 150 kD avian osteoclast surface antigen that is related to superoxide dismutase, a protective free radical scavenging enzyme and is essential for osteoclastic bone resorption.
Acid Phosphatase↗