Gene Expression of Noncollagenous Bone Matrix Proteins in the Limb Joints and Intervertebral Disks of the twy Mouse

The twy (tiptoe walking Yoshimura) mouse is an autosomal recessive mutant manifesting multiple osteochondral lesions characterized by pathologic calcium deposition. To elucidate the pathophysiology of the limb joint lesions and the intervertebral disk lesions of the twy mouse, we assessed the mRNA expression of noncollagenous bone matrix proteins such as osteocalcin, osteonectin, osteopontin, and matrix Gla protein (MGP) by in situ hybridization, but only expression of MGP was observed in association with the pathologic calcium deposits in twy mice. Mild degeneration and abnormal growth of the cartilage in contact with the joint capsule was observed at 5 weeks in the articular cartilage of the ankle joint of the twy mouse, and MGP gene expression was observed at the same time. Simultaneous growth of synovial membrane cells and relatively undifferentiated articular cartilage cells in the knee joint, and of cartilage-like cells near the insertion of the cruciate ligament was observed in the twy mouse, and MGP gene expression was found to be present at the same time. Hypertrophy of abnormally proliferated chondrocyte-like cells, which are different from fibrocartilaginous cells of the annulus fibrosus, was observed in the intervertebral disks of the twy mouse at 3 weeks of age, and MGP gene expression was noted at the same time. These findings suggest that abnormal expression of MGP plays a major role in the pathologic calcification of the twy mouse. Received: 14 May 1997 / Accepted: 24 December 1997     

Klotho Gene Polymorphisms are Associated with Osteocalcin Levels but not Bone Density of Aged Postmenopausal Women

Osteoporosis is known to have a strong genetic basis. It has been proposed that polymorphisms within the KL (klotho) gene have a significant effect on aging, in particular, the osteoblast defect of aging. The association between polymorphisms within this gene and biochemical markers of bone formation and resorption, bone structure, and fracture rates was studied in 1,190 postmenopausal women with a mean age of 75 years. Genotyping of these polymorphic sites was carried out using Matrix-Assisted Laser Desorption Ionization—Time of Flight (MALDI-ToF) mass spectrometry. The G allele of SNP c.1775G>A was associated with a lower osteocalcin level than the A allele (P = 0.004) in a codominant model. SNPs C-387T and IVS1+8262c>t both showed nonsignificant associations with osteocalcin (P values of 0.063 and 0.068, respectively), but a haplotype analysis of 2 of 5 haplotypes of the three SNPs with a frequency greater than 4% revealed a significant association with osteocalcin (P = 0.036). None of the individual polymorphisms or haplotypes analyzed showed any associations with a marker of bone resorption the deoxypyridinoline creatinine ratio, bone structure, or fracture data. Therefore, the G polymorphism within the c.1775G>A SNP site and a haplotype including this are associated with a reduced osteoblast product osteocalcin. These data suggest that variation in the KL gene product affects osteoblast activity independent of osteoclast activity but that this defect does not result in an effect on bone structure in this population, perhaps because of “rescue” by other genetic or environmental factors in this population.     

Identification of Full-Length Dentin Matrix Protein 1 in Dentin and Bone

Dentin matrix protein 1 (DMP1) has been identified in the extracellular matrix (ECM) of dentin and bone as the processed NH(2)-terminal and COOH-terminal fragment. However, the full-length form of DMP1 has not been identified in these tissues. The focus of this investigation was to search for the intact full-length DMP1 in dentin and bone. We used two types of anti-DMP1 antibodies to identify DMP1: one type specifically recognizes the NH(2)-terminal region and the other type is only reactive to the COOH-terminal region of the DMP1 amino acid sequence. An approximately 105-kDa protein, extracted from the ECM of rat dentin and bone, was recognized by both types of antibodies; and the migration rate of this protein was identical to the recombinant mouse full-length DMP1 made in eukaryotic cells. We concluded that this approximately 105-kDa protein is the full-length form of DMP1, which is considerably less abundant than its processed fragments in the ECM of dentin and bone. We also detected the full-length form of DMP1 and its processed fragments in the extract of dental pulp/odontoblast complex dissected from rat teeth. In addition, immunofluorescence analysis showed that in MC3T3-E1 cells the NH(2)-terminal and COOH-terminal fragments of DMP1 are distributed differently. Our findings indicate that the majority of DMP1 must be cleaved within the cells that synthesize it and that minor amounts of uncleaved DMP1 molecules are secreted into the ECM of dentin and bone.     

芪蛭降糖胶囊对糖尿病肾病大鼠肾组织血管内皮细胞生长因子及细胞外基质的影响

目的：观察芪蛭降糖胶囊对糖尿病肾病（diabetic nephropathy,DN）大鼠肾组织血管内皮细胞生长因子（vascu-lar endothelial growth factor,VEGF）及细胞外基质（extracellular matrix,ECM）的影响。方法：清洁级6-7周龄雄性 Wister 大鼠48只,按体重随机取40只,采用切除右肾加腹腔注射链脲佐菌素（strephozotocin,STZ）的方法制备 DN 模型。模型成功后按照血糖高低排序,两头抽取随机分为模型组、缬沙坦对照组（简称对照组）、芪蛭降糖胶囊低剂量组、芪蛭降糖胶囊高剂量组,每组10只大鼠。另取8只正常大鼠行右肾假切除术,腹腔注射等量柠檬酸缓冲液作为假手术组。成模2 d 起各组给予相应浓度和剂量的药物灌胃,分别于4周、8周观察血肌酐（Scr）、尿素氮（BUN）、血清胱抑素- C（Cystatin - C）、β2-微球蛋白（β2- MG）、24 h 尿蛋白定量（24 h TP）、尿微量白蛋白（mAlb）、尿微量白蛋白/尿肌酐（UmAlb/ Ucr）。8周后处死动物,肾组织行 HE 染色,光镜下观察肾组织病变,电镜下观察肾组织足细胞的变化。免疫组化检测 VEGF、基质金属蛋白酶9（MMP -9）、基质金属蛋白酶抑制因子-1（TIMP -1）、纤维黏连蛋白（FN）、Ⅳ型胶原蛋白（ColⅣ）的表达。结果：在各个时间点,模型组大鼠血 Scr、BUN、Cystatin - C、β2- MG,尿24 h TP、mAlb、UmAlb/ Ucr 均明显高于假手术组（P ﹤0．05）,对照组明显低于模型组（P ﹤0．05）,中药组显著低于对照组和模型组,且呈剂量依赖关系（P ﹤0．05-0．01）。与模型组和对照组相比,HE 染色显示芪蛭降糖胶囊能减轻 DN 大鼠肾组织及其血管病理损害。电镜观察显示,芪蛭降糖胶囊能明显减轻 DN 大鼠肾组织基底膜增厚、内皮细胞及系膜增生,减轻足细胞足突融合,且呈剂量依赖关系。免疫组化显示 VEGF、TIMP -1、FN、ColⅣ在模型组的表达较假手术组     

Patterns and Localization of Gene Expression During Intramembranous Bone Regeneration in the Rat Femoral Marrow Ablation Model

Tissue formation and repair are dependent upon cascades of biological events, but the signals involved and the possible gene coexpression patterns during intramembranous bone repair are only poorly understood. We sought to place this mode of regeneration in context by profiling quantitative gene expression for a panel of 39 genes between days 1 and 14 following rat femoral marrow ablation. In situ hybridization was employed to localize a subset of genes. Additionally, principal components analysis was conducted to identify underlying factors suggestive of coexpression patterns. During inflammation (days 1–5), several genes, including cyclooxygenase-1 and -2, showed downregulation. Other proinflammatory cytokines, tumor necrosis factor-α and interleukin-1β, exhibited increasing levels around day 5. During repair (days 3–10), growth factors, receptors, and inhibitor genes for transforming growth factor- β; basic fibroblast growth factor; bone morphogenetic proteins 2, 4, and 7; vascular endothelial growth factor; and insulin-like growth factor-I were upregulated. In addition, the gene for core binding factor-α1 and markers of osteoblast function such as alkaline phosphatase, collagen type I, osteonectin, osteopontin, and osteocalcin had peak expression at day 5 or 7. The remodeling phase (days 10–14) was characterized by peaks for cytokines associated with osteoclastic activity including receptor activator of nuclear factor-κB, receptor activator of nuclear factor-κB ligand (RANKL), cathepsin K, tumor necrosis factor-α, interleukin-6, and cyclooxygenase-2. In situ hybridization showed that the most common sites of increased signal were within osteoblastic cells on trabecular and endosteal surfaces. Principal components analysis identified eight underlying factors that together explained over 80% of the variance in the data. Shinji Kuroda and Amarjit S. Virdi, contributed equally to this report.     

三七总皂苷对5/6肾切除大鼠肾脏皮质细胞外基质积聚的影响

目的：观察三七总皂苷（PNS）对5/6肾切除大鼠肾皮质细胞外基质（ECM）积聚的影响,并探讨其肾脏保护机制。方法：将45只Wistar大鼠按体重随机取8只为正常对照组,余用5/6肾切除法建立慢性肾衰竭（CRF）动物模型。将造模成功后的大鼠随机分为模型组、百令胶囊组（简称对照组）、PNS低剂量组（低剂量组）、PNS高剂量组（高剂量组）,分别给与相应浓度和剂量的药物,实验期间测定大鼠的尿蛋白、肾功能,治疗12周后观察其肾脏病理改变,用半定量方法计算肾小球硬化指数（GSI）和肾小管损伤指数,免疫组化法检测肾小球Ⅳ型胶原（ColⅣ）、纤连蛋白（FN）和肾皮质基质金属蛋白（MMP-2）和金属蛋白酶组织抑制物（TIMP-2）蛋白表达。结果：PNS能明显减少CRF大鼠尿蛋白的排出（P〈0.05）,有一定改善肾功能的作用;PNS能减轻肾脏病理损害,减轻肾小球硬化、肾小管损伤程度;PNS能下调TIMP-2蛋白表达,增加MMP-2活性,抑制了FN、ColⅣ在肾组织的表达（P〈0.01）,减轻ECM积聚。结论：PNS可能通过减少5/6肾切除大鼠尿蛋白的排出,增加肾脏MMP-2活性,降低TIMP-2表达,增加ECM降解,减轻肾小球硬化,从而起到治疗作用。     

连黄降浊颗粒对5/6肾切除大鼠肾功能和肾皮质细胞外基质积聚的影响

目的：观察连黄降浊颗粒对5/6肾切除大鼠肾功能和肾皮质细胞外基质（ECM）积聚的影响。方法：将45只Wistar大鼠随机取8只为正常对照组,余用5/6肾切除法建立慢性肾衰竭（CRF）动物模型,将造模成功后的大鼠随机分为模型组、尿毒清颗粒组（对照组）、连黄降浊颗粒低剂量组（低剂量组）、连黄降浊颗粒高剂量组（高剂量组）,分别给予相应浓度和剂量的药物。实验期间测定大鼠的肾功能、尿蛋白,治疗12周后观察其肾脏病理改变,免疫组化法检测肾小球Ⅳ型胶原（ColⅣ）、纤连蛋白（FN）和肾皮质基质金属蛋白（MMP-2）和金属蛋白酶组织抑制物（TI MP-2）蛋白表达。结果：连黄降浊颗粒能明显改善CRF大鼠肾功能、减少尿蛋白的排出（P〈0.05～0.01）,减轻肾脏病理损害;连黄降浊颗粒能下调TI MP-2蛋白表达,增加MMP-2活性,抑制了FN、ColⅣ在肾组织的表达（P〈0.01）,减轻ECM积聚。结论：连黄降浊颗粒可明显改善肾功能,增加肾脏MMP-2活性,降低TI MP-2表达,增加ECM降解,减轻肾小球硬化。     

Expression of collagen,osteocalcin, and bone alkaline phosphatase in a mineralizing rat osteoblastic cell culture

Summary Rat calvaria bone cells isolated by collagenase digestion form a bone-like matrix which mineralizes in vitro in the presence of -glycerophosphate, in less than 2 weeks. The purpose of this work was to investigate, in this mineralizing rat osteoblastic cell culture, the synthesis of collagen, osteocalcin, and bone alkaline phosphatase (ALP). The results obtained indicate (1) After 15 days in culture, the extracellular-matrix contains collagen type I, V, and to some extent type III. Metabolic labeling at day 14, during the phase of nodules mineralization as well as new nodules formation, shows that collagen types I and type V are synthesized; (2) During the phase of cell growth, no osteocalcin could be detected in the medium, however, at the point of nodule formation, the osteocalcin level reached values of 3.55±1.39 ng/ml, followed by a 30-fold increase after nodules became mineralized. At day 14, after metabolic labeling, de novo synthesized osteocalcin was chromatographed on an immunoadsorbing column. With urea-SDS PAGE the apparent molecular weight was determined to be 9,000 daltons. (3) Specific activity of ALP was found to be 10 nmol/min/mg of proteins at cell confluence. At day 15, when nodules are mineralized, this activity was increased by 40-fold. The Michaelis constant was 1.58 10^-3 M/L. ALP was inhibited by L-homoarginine and levamisole but not by L-phenylalanine. ALP was shown to be heat sensitive at 56°C with two slopes of inhibition. On SDS-PAGE, apparent molecular weight of ALP showed one band at 116,000 daltons (d) when extracted at cell confluence and two bands at 116,000 and 140,000 d when extracted at the 15th day of culture. ³²P-labeled subunit of the enzyme migrated as one band at 75,000 d. Sialic acid content was demonstrated by neuraminidase treatment either on the dimeric form or on the ³²P-labeled subunit. These data indicate that ALP expressed in this culture is bone specific. The results of the present study show that this mineralizing rat osteoblastic cell culture system synthesizes collagen type I, V, and traces of type III, osteocalcin, and bone ALP isoenzyme. Medium osteocalcin was detected during nodule formation and increased during mineralization. Increase in ALP activity as well as the presence of an additional form of ALP occurred in the mineralization phase. Therefore, this culture may be a useful model for studying the functions of bone-specific proteins during the process of mineralization.     

Characterization of Matrix-Induced Osteogenesis in Rat Calvarial Bone Defects: I. Differences in the Cellular Response to Demineralized Bone Matrix Implanted in Calvarial Defects and in Subcutaneous Sites

The cellular and biochemical sequences of osteogenesis induced by implanting demineralized bone matrix (DBM) in rat cranial defects and in subcutaneous sites have been studied by histological, histochemical, and biochemical techniques from days 2 to 28 after implantation. In subcutaneous sites, allogenic DBM induced cartilage cells and matrix for approximately the first 10 days which were subsequently resorbed and replaced by bone with little evidence for the classical endochondral sequence of ossification. In sharp contrast, the first cells that differentiated from the mesenchymal stem cells in the cranial defects were alkaline phosphatase (ALP) positively stained osteoblasts that appeared 3 days after implantation followed by synthesis of bone matrix which calcified shortly thereafter. A few clusters of cartilage cells were observed beginning at days 6–7 which were spatially distinct from the new bone and later resorbed. By day 28 the tissue induced in both the subcutaneous and cranial sites consisted almost solely of bone; however, the total amount of new bone in the subcutaneous implants was significantly less than the mass of bone formed in the calvarial defects. Bovine DBM induced bone formation in rat cranial defects to a very much lesser extent than allogenic DBM. A few cartilage cells were induced by bovine DBM in subcutaneous sites and rapidly resorbed and not replaced with bone. These results clearly indicate that the cellular sequence induced by allogenic and xenogenic DBM and the repair tissues synthesized are distinctly different in the cranial defects from those induced in the subcutaneous sites. Received: 1 September 1998 / Accepted: 15 January 1999     

The Asn19Lys Substitution in the Osteoclast Inhibitory Lectin (OCIL) Gene is Associated with a Reduction of Bone Mineral Density in Postmenopausal Women

Osteoclast inhibitory lectin (OCIL) is a newly recognized inhibitor of mouse and human osteoclast differentiation whose cellular expression is similar to that of receptor activator of nuclear factor kappaB (RANKL). The main objective of the present work was to elucidate whether naturally occurring single-nucleotide polymorphisms (SNPs) in this gene could be associated with bone mass in postmenopausal women. To that end, we studied the association of bone mineral density (BMD) measured by dual-energy X-ray absorptiometry with two nonsynonymous SNPs in the OCIL gene resulting in Asn19Lys and Leu23Val substitutions in a population of 500 postmenopausal Spanish women. A weak association was detected for Asn19Lys SNP with femoral neck (FN) BMD and lumbar spine (LS) BMD in the whole population. When the population was stratified by age, however, the association was strong in older women (> or =53 years). Thus, in this group of participants, women with CG/GG genotype displayed reductions of 5.6% and 6.7% in FN BMD and LS BMD adjusted by age and body mass index (BMI), respectively, compared to women with CC genotype. The Asn19Lys SNP alleles explained about 7% of BMD variance in older women but only 1.7-3.9% in the whole population in regression models including age and BMI. In conclusion, women with a lysine (GG genotype) at position 19 of the OCIL protein displayed lower BMD at femoral neck and at lumbar spine sites than women having an asparagine residue. Since the OCIL protein inhibits osteoclast differentiation, this amino acid substitution could have consequences for OCIL functionality.     

Effectiveness of Bombesin and Saccharomyces boulardii Against the Translocation of Candida albicans in the Digestive Tract in Immunosuppressed Rats

Purpose We investigated the effects of bombesin on disseminated candidiasis, and compared the effectiveness of bombesin with Saccharomyces boulardii against Candida albicans translocation from the gastrointestinal tract in immunosuppressed rats.Methods Sixty rats were divided into five groups of 12. Group 1 was given only a laboratory pellet diet and water during the experiments; the other four groups were orally inoculated with C. albicans; and groups 3, 4, and 5 were also given prednisolone intraperitoneally. The treatment groups consisted of group 4, given S. boulardii orally, and group 5, given bombesin subcutaneously. The rats were killed after 10 days, and the large bowel, liver, spleen, and kidneys were removed for microbiological and histopathological examination. Blood samples were taken to measure tumor necrosis factor-α (TNF-α) and interleukin-1 β (IL-1β) levels, and the results were compared.Results The number of translocated C. albicans colonies from the gastrointestinal tract and the serum TNF-α and IL-β levels were significantly lower in groups 4 and 5 than in group 3 (P < 0.05). Histological analysis revealed that the bombesin-treated group (group 5) had significantly less mucosal ulceration and submucosal inflammation in the large bowel, less inflammation and necrosis in the liver, and less inflammation of the Bowman capsules in the kidney than the S. boulardii-treated group (group 4) (P < 0.05).Conclusions These findings show that both S. boulardii and bombesin inhibit the translocation of C. albicans from the gastrointestinal tract, although mucosal ulceration, submucosal inflammation in the large bowel, and dissemination in the liver and kidneys were significantly less severe in the bombesin-treated immunosuppressed rats.     

Association of PLOD1 polymorphisms with bone mineral density in a population-based study of women from the UK

The PLOD1 gene is situated within a quantitative trait locus for regulation of bone mineral density (BMD) on chromosome 1p36 and is a strong functional candidate for the regulation of BMD and bone quality. PLOD1 encodes the enzyme procollagen-lysine, 2-oxoglutarate 5-dioxegenase (lysyl hydroxylase; EC 1.14.11.4), which catalyses the hydroxylation of lysine residues during the posttranslational modification of type I collagen, the major protein of bone. We investigated the role of PLOD1 as a genetic determinant of osteoporosis by studying two coding polymorphisms located in exon 3 of the PLOD1 gene in relation to BMD and bone loss in a population-based cohort of 678 Scottish women. We observed a significant association between lumbar spine (LS) BMD and a polymorphism at nucleotide 386 (G386A) of PLOD1, which results in an alanine-threonine amino acid change at codon 99 (A99T). Heterozygotes for G386A had significantly reduced LS-BMD when compared with the other genotype groups, and the difference remained significant after correcting for confounding factors. A similar association was observed between LS-BMD and a conservative polymorphism at position 385 (C385T), but this was in strong linkage disequilibrium (LD) with G386A. There was no evidence for an allele dose effect for either polymorphism, and the strongest association was observed in heterozygotes. No association was found between PLOD1 alleles and femoral-neck BMD or bone loss, but the hydroxylysylpyridinoline to lysylpyridinoline ratio was significantly increased in G386A heterozygotes compared with other genotype groups, suggesting a functional effect of this polymorphism on enzyme activity. Our findings show that heterozygosity for the A99T variant of PLOD1 is associated with reduced LS-BMD and an altered ratio of hydroxylysylpyridinoline to lysylpyridinoline. Whilst further studies will be required to confirm and extend these observations, our studies raise the possibility that A99T heterozygosity might affect lysyl hydroxylase function and regulate bone mass.     

Expression of bone sialoprotein (BSP) in developing human tissues

Summary Bone sialoprotein (BSP) and its messenger RNA were localized in developing human skeletal and nonskeletal tissues by means of immunohistochemistry andin situ hybridization. Both protein and mRNA were found in mature, bone-forming cells but not in their immature precursors. In addition, osteoclasts displayed positive immunostaining and high densities of autoradiographic grains byin situ hybridization experiments. BSP was expressed in fetal epiphyseal cartilage cells, particularly in hypertrophic chondrocytes of growth plates. Though neither the protein nor the mRNA were identified in a variety of other connective and nonconnective tissues, an unexpected finding was the expression of BSP in the trophoblast cells of placenta. These findings show that BSP is primarily an osteoblast-derived component of the bone matrix expressed at late stages of differentiation. We have also found that osteoclasts produce BSP, possibly as a mediator of cell attachment to bone.     

FokI Polymorphism of the Vitamin D Receptor Gene Correlates with Parameters of Bone Mass and Turnover in a Female Population of the Italian Island of Lampedusa

One of the most promising genetic approaches to dissecting a multifactorial disease is represented by genetically isolated population studies. We studied a genetic marker in a cohort of women living on the Mediterranean island of Lampedusa, a geographically isolated population. Lampedusa, located between the African coast and Sicily, consists of a young genetic isolate (<20 generations) with an exponential growth in the last generations. We analyzed the association between the FokI vitamin D receptor (VDR) gene polymorphism, previously proposed as a predictor of bone mass, with parameters of bone mass and turnover in a cohort of pre- and postmenopausal women living on Lampedusa. In 424 women (277 postmenopausal and 147 premenopausal), allelic frequencies were 49% for the F allele and 51% for the f allele. Using analysis of covariance, we found that subjects with ff genotype exhibited a significantly (P < 0.001) lower lumbar spine bone mass, by dual-energy X-ray absorptiometry, and lower values of bone ultrasonographic parameters (speed of sound and broadband ultrasound attenuation) relative to those with Ff and FF genotypes. Conversely, osteocalcin and serum cross-laps were significantly higher in ff and Ff compared to FF genotype. Our data suggest that FokI VDR polymorphism may contribute to the determination of bone mass and turnover in both pre- and postmenopausal women in this geographically isolated population.     

Genetic Polymorphisms of OPG, RANK, and ESR1 and Bone Mineral Density in Korean Postmenopausal Women

To evaluate the effects of genetic polymorphisms of OPG, RANK, and ESR1, which regulate osteoclastogenesis, on bone mineral density (BMD), a cross-sectional study was conducted in 650 Korean postmenopausal women. BMDs of the distal radius and the calcaneus were measured by dual energy X-ray absorptiometry (DXA). Genetic polymorphisms of OPG 163 A > G, 1181 G > C; RANK 421 C > T, 575 T > C; and ESR1 1335 C > T, 2142 G > A were determined by matrix-assisted laser desorption/ionization—time of flight (MALDI-ToF) mass spectrometry. The differences between the BMDs of the genotypes of OPG, RANK, and ESR1 were analyzed by multiple linear regression model adjusted for age and body mass index. Women with the OPG 1181 CC genotype had higher BMDs at the distal radius (7%) and calcaneus (10%) than those with the GG genotype; and these differences were statistically significant (P = 0.001 and P = 0.007, respectively). A significant association was also observed between RANK 575 T > C and calcaneus BMD (P for trend = 0.017). No significant association was observed between BMDs and the polymorphisms of ESR1. The association between OPG 1181 G > C and BMD was profound in subjects with the RANK 575 TT or ESR1 2142 GG genotypes; women with OPG 1181 CC had higher BMDs at the distal radius (11%) and calcaneus (11%) than those with OPG 1181 GG only in women with RANK 575 TT genotype (P = 0.002 and P = 0.021, respectively). These results suggest that OPG genetic polymorphisms, especially with the RANK 575 TT or ESR1 2142 GG genotypes, are related to low BMD in postmenopausal Korean women.     

The effects of <Emphasis Type="Italic">Acanthopanax senticosus</Emphasis> extract on bone turnover and bone mineral density in Korean postmenopausal women

The purpose of this prospective randomized study was to investigate the effects of the extract of Acanthopanax senticosus (AS extract), a widely used oriental herb, on bone remodeling and bone mineral density in Korean postmenopausal women. A total of 81 postmenopausal women with osteopenia or osteoporosis, an age of less than 65 years, were enrolled in the study. Subjects were randomly assigned to two groups: (1) the control group (n = 40), calcium intake (500 mg per day), and (2) the treatment group (n = 41), calcium (500 mg per day) plus AS extract (3 g per day). After treatment with AS extract for 6 months, the AS extract group showed a significant increase in serum osteocalcin levels compared with the control group (P = 0.041). However, no significant changes in bone mineral density were observed by dual-energy X-ray absorptiometry (DXA). AS extract was generally well tolerated, and no differences were observed between the two groups in terms of adverse events. This study suggests that AS extract supplementation may have beneficial effects on bone remodeling in Korean postmenopausal women and that it has no significant adverse events.     

Assessing the Use of p16 Promoter Gene Methylation in Serum for Detection of Bladder Cancer

Objective: This study was undertaken to investigate whether hypermethylation in p16^INK4a gene promoter could serve as plasma biomarker of bladder cancer.Methods and Patients: We examined the p16^INK4a status using methylation-specific PCR in 86 cancer patients and 49 controls (31 healthy people and 18 patients with benign urological diseases).Results: The p16^INK4a methylation was found in 22% of the serum samples and in 26% of the bladder cancer biopsies; one of them with carcinoma in situ. The presence of hypermethylated p16^INK4a in serum seems to be a product from tumour cells because a strong statistical association was found between both matched DNA signals (p<0.0001). Using the control group, the presence of methylated p16^INK4a in the serum of individuals with suspicion of bladder cancer was found to be associated with the tumour presence (p=0.0009). Aberrant p16^INK4a methylation was also observed in one non-cancer patient, which is undergoing further assessment.Conclusions: According with our results, methylation of p16^INK4a promoter may be involved in the bladder cancer genesis and the presence of p16^INK4a methylated in serum of these patients could be useful in the cancer diagnosis with values of sensitivity, specificity and positive predictive value of 0.226, 0.950 and 0.98, respectively. These figures support the use of methylated p16^INK4a as a new class of tumour marker in bladder cancer.     

Polymorphisms in <Emphasis Type="Italic">ALOX12</Emphasis>, but not <Emphasis Type="Italic">ALOX15</Emphasis>, Are Significantly Associated With BMD in Postmenopausal Women

The murine arachidonate 15-lipoxygenase gene (Alox15) has recently been identified as a negative regulator of peak bone mineral density (BMD). The human ALOX15 gene shares significant sequence homology with the murine Alox15 gene; however, the human arachidonate 12-lipoxygenase gene (ALOX12) is functionally more similar to the mouse gene. Multiple single-nucleotide polymorphisms (SNPs) in the human ALOX15 and ALOX12 genes have previously been reported to be significantly associated with BMD in humans. On the basis of these data, we carried out our own investigation of the human ALOX15 and ALOX12 genes and their relationship with hip and spine BMD parameters. The study population consisted of 779 postmenopausal women with a mean (± standard deviation) age of 62.5 ± 5.9 years at BMD measurement and was recruited from a single large general practice in Chingford, northeast London. Three SNPs from ALOX15 and five from ALOX12 were analyzed. None of the SNPs that we analyzed in ALOX15 were significantly associated with any of the BMD parameters or fracture data. However, we found that three SNPs from ALOX12, all previously associated with spine BMD in women, were significantly associated with spine and various hip BMD parameters in our cohort (P = 0.029–0.049). In conclusion, we found no association between polymorphism in ALOX15 and BMD phenotypes but were able to replicate previous findings that genetic variation in ALOX12 seems to play a role in determining bone structure in Caucasian women.     

<Emphasis Type="Italic">In Vivo</Emphasis> Mechanical Loading Modulates Insulin-Like Growth Factor Binding Protein-2 Gene Expression in Rat Osteocytes

Mechanical stimulation is essential for maintaining skeletal integrity. Mechanosensitive osteocytes are important during the osteogenic response. The growth hormone-insulin-like growth factor (GH-IGF) axis plays a key role during regulation of bone formation and remodeling. Insulin-like growth factor binding proteins (IGFBPs) are able to modulate IGF activity. The aim of this study was to characterize the role of IGFBP-2 in the translation of mechanical stimuli into bone formation locally in rat tibiae. Female Wistar rats were assigned to three groups (n = 5): load, sham, and control. The four-point bending model was used to induce a single period of mechanical loading on the tibial shaft. The effect on IGFBP-2 mRNA expression 6 hours after stimulation was determined with nonradioactive in situ hybridization on decalcified tibial sections. Endogenous IGFBP-2 mRNA was expressed in trabecular and cortical osteoblasts, some trabecular and subendocortical osteocytes, intracortical endothelial cells of blood vessels, and periosteum. Megakaryocytes, macrophages, and myeloid cells also expressed IGFBP-2 mRNA. Loading and sham loading did not affect IGFBP-2 mRNA expression in osteoblasts, bone marrow cells, and chondrocytes. An increase of IGFBP-2 mRNA-positive osteocytes was shown in loaded (1.68-fold) and sham-loaded (1.35-fold) endocortical tibial shaft. In conclusion, 6 hours after a single loading session, the number of IGFBP-2 mRNA-expressing osteocytes at the endosteal side of the shaft and inner lamellae was increased in squeezed and bended tibiae. Mechanical stimulation modulates IGFBP-2 mRNA expression in endocortical osteocytes. We suggest that IGFBP-2 plays a role in the lamellar bone formation process.