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Collagen Type I (collagen + type_i)
Selected AbstractsCalcaneal ultrasonometry in patients with Charcot osteoarthropathy and its relationship with densitometry in the lumbar spine and femoral neck and with markers of bone turnoverDIABETIC MEDICINE, Issue 6 2001A. Jirkovská Abstract Aims To assess calcaneal ultrasonometry in Charcot osteoarthropathy (CO) and to compare it with densitometry measured by dual energy X-ray absorptiometry (DEXA) and with bone remodelling markers. Patients and methods A group of 16 diabetic patients in the acute stage of CO with a mean age (± sd) of 51 ± 13 years was compared with 26 sex- and age-matched control subjects. Both calcaneal quantitative ultrasound (QUS) parameter stiffness and bone mineral density (BMD) measured in lumbar spine and femoral neck by DEXA were compared. Collagen type I cross-linked C-telopeptides (ICTP) were used for assessment of bone resorption. Results Patients with acute CO had significantly lower stiffness of the calcaneus in the Charcot and non-Charcot foot (both P < 0.001) and significantly lower femoral neck BMD (P < 0.05) in comparison with the control group. The T-score of stiffness was significantly lower in the Charcot foot compared with the non-Charcot foot (,3.00 ± 1.39 vs. ,2.36 ± 1.12; P < 0.01) and significantly lower than the mean T-score of BMD in the lumbar spine (,0.57 ± 1.28; P < 0.001) and femoral neck (,1.58 ± 1.24; P < 0.05). A significant difference in ICTP (8.49 ± 4.37 vs. 3.92 ± 2.55 ng/ml; P < 0.001) between patients with CO and the control group was found, and a significant correlation was demonstrated between ICTP and the T-score of stiffness (r = ,0.73; P < 0.01). Conclusion The lower calcaneal QUS parameter stiffness in the Charcot foot in comparison with the control group, with the non-Charcot foot and with BMD in the lumbar spine and femoral neck, and its association with increased bone resorption indicate that calcaneal ultrasonometry may be useful in diagnosing the acute stage of CO and in assessing the risk of foot fracture. Diabet. Med. 18, 495,500 (2001) [source] Temporal expression of growth factors and matrix molecules in healing tendon lesionsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2005Linda A. Dahlgren Abstract Overuse tendon injuries are common among elite and recreational athletes. Tendon healing may be enhanced at the cellular level through the use of exogenous growth factors; however, little is known about the endogenous expression of growth factors in healing tendon. This study describes the temporal expression of insulin-like growth factor-I (IGF-I), transforming growth factor-,1 (TGF-,1), and collagen types I and III in healing tendon lesions. Collagenase-induced lesions were created in the tensile region of the flexor digitorum superficialis tendon of both forelimbs of 14 horses. Tendons were harvested from euthanatized horses 1, 2, 4, 8 or 24 weeks following injury. Gene expression was evaluated using Northern blot analysis (collagen types I and III), real time PCR (IGF-I and TGF-,1), and in situ hybridization. Protein content was assayed by dye-binding assay (collagen types I and III), radioimmunoassay (IGF-I), ELISA (TGF-,1), and immunohistochemistry. Samples were also processed for differential collagen typing. DNA and glycosaminoglycan content, and routine H&E staining. Microscopically, lesions progressed from an amorphous, acellular lesion soon after injury to scar tissue filled with collagen fibers and mature fibroblasts organized along lines of tension. Early lesions were characterized by immediate increases in expression of growth factors and collagen. Message levels for TGF-,1 peaked early in the wound healing process (1 week), while IGF-I peaked later (4 weeks), as the regenerative phase of healing was progressing. In the first 2 weeks after lesion induction, tissue levels of IGF-I protein actually decreased approximately 40% compared to normal tendon. By 4 weeks, these levels had exceeded those of normal tendon and remained elevated through 8 weeks. Message expression for collagen types I and III increased by 1 week following injury and remained elevated throughout the course of the study. Collagen type I represented the major type of collagen in healing tendon at all time points of the study. Based on these results, IGF-I, administered exogenously during the first 2 weeks following injury, may provide a therapeutic advantage by bolstering low endogenous tissue levels and enhancing the metabolic response of individual tendon fibroblasts. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Increases in collagen type I synthesis in asthma: the role of eosinophils and transforming growth factor-b,CLINICAL & EXPERIMENTAL ALLERGY, Issue 6 2002A. Nomura Summary Background Collagen type I is one of the major deposits in thickening of the reticular basement membrane of asthma. Objective and Methods In this study, we assessed turnover of collagen type I in asthma by measuring procollagen type I C-terminal peptide (PICP) and collagen type I C-terminal telopeptide (ICTP) in induced sputum. Results PICP but not ICTP was found to be significantly higher in asthma subjects than in normal volunteers (P < 0.05). In asthma, PICP was inversely correlated with %FEV1.0 (r = ,0.539), and its levels significantly increased upon exacerbation (P < 0.05), indicating that collagen synthesis increases during asthma exacerbation. Additionally, PICP was found to significantly correlate with eosinophil counts in sputum (r = 0.539), indicating that eosinophils stimulate collagen turnover. Because eosinophils can produce TGF-,, a potent stimulator of collagen synthesis, we immunocytochemically examined TGF-,-positive cells in sputum. TGF-,-positive cells significantly correlated with eosinophil counts (r = 0.811) and PICP (r = 0.569), suggesting that TGF-, released from eosinophils is involved in collagen synthesis. Conclusions The results of the present study suggest that collagen synthesis is stimulated in asthmatic airways by eosinophils through TGF-,, while collagen degradation is not, and that PICP in sputum can act as a new marker for airway inflammation in asthma. [source] Collagen types I, III, and V constitute the thick collagen fibrils of the mouse deciduaMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2007Karin Spiess Abstract A mammal's endometrium is deeply remodeled while receiving and implanting an embryo. In addition to cell proliferation and growth, endometrial remodeling also comprises synthesis and degradation of several molecular components of the extracellular matrix. All of these events are orchestrated by a precise sequence of ovarian hormones and influenced by several types of cytokines. As we have previously reported, an intriguing and rapid increase in collagen fibril diameter occurs in the decidualized areas of the endometrium, surrounding the implantation crypt, whereas collagen fibrils situated far from the embryo remain unchanged. Collagen fibrilogenesis is a complex molecular process coordinated by a number of factors, such as the types and amounts of glycosaminoglycans and proteoglycans associated with collagen molecules. Collagen genetic type, mechanical stress, aging, and other factors not yet identified also contribute to this development. A recent study suggests that thick fibrils from mouse decidua are formed, at least in part, by aggregation of thin fibrils existing in the stroma before the onset of decidualization. In the present ultrastructural study using single and double immunogold localization, we showed that both thin and thick collagen fibrils present in the mouse pregnant endometrium endometrium are heterotypic structures formed at least by type I, type III, and type V collagens. However, type V collagen predominates in the thick collagen fibrils, whereas it is almost absent of the thin collagen fibrils. The putative role of type V homotrimer in the rapid increase of the diameter of collagen fibrils of the mouse decidua is discussed. Microsc. Res. Tech., 2006. © 2006 Wiley-Liss, Inc. [source] Increased expression of collagen receptors: ,1,1 and ,2,1 integrins on blood eosinophils in bronchial asthmaCLINICAL & EXPERIMENTAL ALLERGY, Issue 9 2006S. Bazan-Socha Summary Background Eosinophils are one of the major effector cells in bronchial asthma. Their infiltration of airways correlates with the asthma severity. Recruitment and activation of eosinophils are partially mediated by integrins ,4,1 and ,4,7. Collagens type I and IV constitute important components of extracellular matrix and vascular basement membrane, respectively. Therefore, collagen-binding integrins (,1,1 and ,2,1) may also play a role in eosinophil lung infiltration. Objective To evaluate the possible presence of ,1,1 and ,2,1 integrins on peripheral blood eosinophils from asthmatic subjects. Methods Collagen receptors were studied on eosinophils separated by immunomagnetic CD16-negative method from healthy donors (n=13) and patients with moderate persistent atopic bronchial asthma (n=15). Surface receptor identification was performed by flow cytometry and cell adhesion assay. Results Eosinophils isolated from the patients showed increased expression of both ,1,1 and ,2,1 integrins as compared with healthy controls. Moreover, adhesive function of eosinophils to collagen type IV was inhibited by snake venom disintegrins: viperistatin and obtustatin. These disintegrins contain KTS active motif and are specific inhibitors of ,1,1 integrin. Conclusion We demonstrated for the first time that collagen receptors: ,1,1 and ,2,1 integrins are overexpressed on the surface of peripheral blood eosinophils of asthmatic subjects. Further studies may reveal potential application of KTS-disintegrins or their structural analogs for therapy of bronchial asthma. [source] Encapsulation of adult human mesenchymal stem cells within collagen-agarose microenvironments,BIOTECHNOLOGY & BIOENGINEERING, Issue 4 2005Anna Batorsky Abstract Reliable control over the process of cell differentiation is a major challenge in moving stem cell-based therapies forward. The composition of the extracellular matrix (ECM) is known to play an important role in modulating differentiation. We have developed a system to encapsulate adult human mesenchymal stem cells (hMSC) within spherical three-dimensional (3D) microenvironments consisting of a defined mixture of collagen Type I and agarose polymers. These protein-based beads were produced by emulsification of liquid hMSC-matrix suspensions in a silicone fluid phase and subsequent gelation to form hydrogel beads, which were collected by centrifugation and placed in culture. Bead size and size distribution could be varied by changing the encapsulation parameters (impeller speed and blade separation), and beads in the range of 30,150 microns in diameter were reliably produced. Collagen concentrations up to 40% (wt/wt) could be incorporated into the bead matrix. Visible light and fluorescence microscopy confirmed that the collagen matrix was uniformly distributed throughout the beads. Cell viability post-encapsulation was in the range of 75,90% for all bead formulations (similar to control slab gels) and remained at this level for 8 days in culture. Fluorescent staining of the actin cytoskeleton revealed that hMSC spreading increased with increasing collagen concentration. This system of producing 3D microenvironments of defined matrix composition therefore offers a way to control cell-matrix interactions and thereby guide hMSC differentiation. The bead format allows the use of small amounts of matrix proteins, and such beads can potentially be used as a cell delivery vehicle in tissue repair applications. © 2005 Wiley Periodicals, Inc. [source] Simulated microgravity activates MAPK pathways in fibroblasts cultured on microgrooved surface topographyCYTOSKELETON, Issue 2 2008W. A. Loesberg Abstract This study evaluated in vitro the differences in morphological behaviour between fibroblast cultured on smooth and microgrooved substrata (groove depth: 0.5 ,m, width: 1 ,m), which were subjected to simulated microgravity. The aim of the study was to clarify which of these parameters was more dominant to determine cell behaviour. Morphological characteristics were investigated using scanning electron microscopy and fluorescence microscopy in order to obtain qualitative information on cell alignment. Expression of collagen type I, and ,1-, ,1-, ,3-integrin were investigated by QPCR. Finally, immunoblotting was applied to visualise MAPK signalling pathways. Microscopy and image analysis showed that the fibroblasts aligned along the groove direction on all textured surfaces. On the smooth substrata, cells had spread out in a random fashion. The alignment of cells cultured on grooved surfaces under simulated microgravity, after 48 h of culturing appeared similar to those cultured at 1g, although cell shape was different. Analysis of variance proved that all main parameters: topography, gravity force, and time were significant. In addition, gene levels were reduced by simulated microgravity particularly those of ,3-integrin and collagen, however alpha-1 and beta-1 integrin levels were up-regulated. ERK1/2 was reduced in RPM, however, JNK/SAPK and p38 remained active. The members of the small GTPases family were stimulated under microgravity, particularly RhoA and Cdc42. The results are in agreement that application of microgravity to fibroblasts promotes a change in their morphological appearance and their expression of cell-substratum proteins through the MAPK intracellular signalling pathways. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source] The effect of combined simulated microgravity and microgrooved surface topography on fibroblastsCYTOSKELETON, Issue 3 2007W. A. Loesberg Abstract This study evaluated in vitro the differences in morphological behaviour between fibroblast cultured on smooth and microgrooved substrata (groove depth: 0.5 ,m, width: 1, 2, 5, and 10 ,m), which were subjected to simulated microgravity. The aim of the study was to clarify which of these parameters was more dominant to determine cell behaviour. Morphological characteristics were investigated using scanning electron microscopy and fluorescence microscopy in order to obtain qualitative information on cell alignment and area. Confocal laser scanning microscopy visualised distribution of actin filaments and focal adhesion points. Finally, expression of collagen type I, fibronectin, and ,1- and ,1-integrin were investigated by PCR. Microscopy and image analysis showed that the fibroblasts aligned along the groove direction on all textured surfaces. On the smooth substrata, cells had spread out in a random fashion. The alignment of cells cultured on grooved surfaces decreased under simulated microgravity, especially after 24 h of culturing. Cell surface area on grooved substrata were significantly smaller than on smooth substrata, but simulated microgravity on the grooved groups resulted in an enlargement of cell area. ANOVA was performed on all main parameters: topography, gravity force, and time. In this analysis, all parameters proved significant. In addition, gene levels were reduced by microgravity particularly those of ,1-integrin and fibronectin. From our data it is concluded that the fibroblasts primarily adjust their shape according to morphological environmental cues like substratum surface whilst a secondary, but significant, role is played by microgravity conditions. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source] The effect of combined hypergravity and microgrooved surface topography on the behaviour of fibroblastsCYTOSKELETON, Issue 7 2006W. A. Loesberg Abstract This study evaluated in vitro the differences in morphological behaviour between fibroblast cultured on smooth and microgrooved substrata (groove depth: 1 ,m, width: 1, 2, 5, 10 ,m), which undergo artificial hypergravity by centrifugation (10, 24 and 50 g; or 1 g control). The aim of the study was to clarify which of these parameters was more important to determine cell behaviour. Morphological characteristics were investigated using scanning electron microscopy and fluorescence microscopy in order to obtain qualitative information on cell spreading and alignment. Confocal laser scanning microscopy visualised distribution of actin filaments and vinculin anchoring points through immunostaining. Finally, expression of collagen type I, fibronectin, and ,1 - and ,1 -integrin were investigated by PCR. Microscopy and image analysis showed that the fibroblasts aligned along the groove direction on all textured surfaces. On the smooth substrata (control), cells spread out in a random fashion. The alignment of cells cultured on grooved surfaces increased with higher g-forces until a peak value at 25 g. An ANOVA was performed on the data, for all main parameters: topography, gravity force, and time. In this analysis, all parameters proved significant. In addition, most gene levels were reduced by hypergravity. Still, collagen type 1 and fibronectin are seemingly unaffected by time or force. From our data it is concluded that the fibroblasts primarily adjust their shape according to morphological environmental cues like substratum surface whilst a secondary, but significant, role is played by hypergravity forces. Cell Motil. Cytoskeleton 2006. © 2006 Wiley-Liss, Inc. [source] Comparison of histologic, biochemical, and mechanical properties of murine skin treated with the 1064-nm and 1320-nm Nd:YAG lasersEXPERIMENTAL DERMATOLOGY, Issue 12 2005Yong-Yan Dang Abstract:, The goal of this study was to compare the effects of the Q-switched 1064-nm Nd:YAG laser and the 1320-nm Nd:YAG laser non-ablative treatments on mouse skin in vivo. Skin elasticity measurements were carried out with a Reviscometer, and skin samples were taken for histological study, hydroxyproline content assay and estimation of collagen type I and III. By the second month after non-ablative treatments, the 1064-nm laser treatment resulted in an average of 25% greater improvement of skin elasticity, 6% more increase of dermal thickness, and 11% higher synthesis of hydroxyproline than the 1320-nm laser. Collagen type III increased markedly after the 1064-nm laser treatment whereas more collagen type I was elicited by the 1320-nm laser. Our results demonstrated that the 1064-nm laser was more effective than the 1320-nm Nd:YAG laser in non-ablative treatments, but the results needed to be confirmed in humans. It appeared that photo-mechanic reaction could cause more collagen type III synthesis whereas the photo-thermal effect was in favor of the formation of collagen type I. [source] Stimulation of intramembranous bone repair in rats by ghrelinEXPERIMENTAL PHYSIOLOGY, Issue 7 2008Feilong Deng Researchers in our laboratory have previously shown that ghrelin, a gastric peptide hormone, may regulate mesenchymal cell differentiation into adipocytes and myocytes. Here we show that ghrelin promotes osteogenesis of intramembranous bone and improves the repair of calvarial bone defects in rats. Rats with a 9 mm full-thickness calvarial bone defect received either Bio-Oss® (control group) or Bio-Oss® mixed with 20 ,g ghrelin (treatment group), followed by local administration of saline or ghrelin (10 ,g), respectively, on days 5, 10 and 15. After 6 and 12 weeks, new bone formation was assessed. Animals treated with ghrelin showed a significant increase in new bone formation as demonstrated by an increment in bone mineral density and fluorescence labelling of tetracycline relative to the control group. At 6 weeks, bone mineral density increased from 54 ± 7 (control group) to 78 ± 9 mg cm,2 in the treatment group, while the tetracycline fluorescence labelling increased by 61 ± 15%. A similar increment was observed at 12 weeks. Quantitative reverse transcriptase-polymerase chain reaction showed that expression of alkaline phosphatase (ALP), osteocalcin and collagen type I was elevated. Relative to the control animals, mRNAs for ALP, osteocalcin and collagen type I increased 2.4 ± 0.4-, 4.7 ± 1.9- and 4.0 ± 1.7-fold, respectively, in animals treated with ghrelin for 6 weeks (P < 0.05). At 12 weeks, mRNA levels of ALP, osteocalcin and collagen type I showed a decline relative to levels at 6 weeks but still remained significantly higher than in the control group, with fold changes of 2.4 ± 0.8, 2.4 ± 1.2 and 2.1 ± 0.7, respectively (P < 0.05). This study demonstrated that ghrelin stimulates intramembranous osteogenesis. [source] Fibroblast activation protein increases apoptosis, cell adhesion, and migration by the LX-2 human stellate cell line,HEPATOLOGY, Issue 4 2005Xin Maggie Wang Injury and repair in chronic liver disease involve cell adhesion, migration, apoptosis, proliferation, and a wound healing response. In liver, fibroblast activation protein (FAP) has both collagenase and dipeptidyl peptidase IV (DPIV) activities and is expressed only by activated hepatic stellate cells (HSC) and myofibroblasts, which produce and degrade extracellular matrix (ECM). FAP was colocalized with collagen fibers, fibronectin, and collagen type I in human liver. FAP function was examined in vitro by expressing green fluorescent protein FAP fusion protein in cell lines cultured on collagen-I, fibronectin, and Matrigel. Glutamates at 203 and 204 as well as serine624 of FAP were essential for peptidase activity. Human embryonic kidney 293T cells overexpressing FAP showed reduced adhesion and migration. FAP overexpression in the human HSC line LX-2 caused increased cell adhesion and migration on ECM proteins as well as invasion across transwells in the absence or presence of transforming growth factor beta-1. FAP overexpression enhanced staurosporine streptomyces,stimulated apoptosis in both cell lines. Interestingly, the enzyme activity of FAP was not required for these functions. Overexpressing FAP increased the expression of matrix metalloproteinase-2 and CD44 and reduced integrin-,1 expression in 293T cells, suggesting potential pathways of FAP-mediated impairment of cell adhesion and migration in this epithelial cell line. In conclusion, these findings further support a pro-fibrogenic role for FAP by indicating that, in addition to its enzymatic functions, FAP has important nonenzymatic functions that in chronic liver injury may facilitate tissue remodeling through FAP-mediated enhancement of HSC cell adhesion, migration, and apoptosis. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270-9139/suppmat/index.html). (HEPATOLOGY 2005;42:935,945.) [source] Type and ultrastructure of Didymocystis wedli and Koellikerioides intestinalis (Digenea, Didymozoidae) cysts in captive Atlantic bluefin tuna (Thunnus thynnus Linnaeus, 1758)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2009I. Mladineo Summary Tissue encapsulation, one of the most common tissue reactions to invading parasites, is the hallmark sign of didymozoid (Digenea, Didymozoidae) infections in fish. Investigated were the types of intermediate filaments and ultrastructure of the connective tissue capsule elicited by the presence of didymozoids in the gills and intestine of Atlantic bluefin tuna (Thunnus thynnus Linnaeus, 1758). The evaluation was done performing TEM microscopy of two tissue-embedded didymozoid species, along with monoclonal antibodies labeling (anti-fish collagen type I, anti-human cytokeratin, anti-vimentin antibodies). Ultrastructure of Didymocystis wedli (Ariola, 1902) (prevalence = 61.75%, abundance = 28.91) encapsulated in gill filaments and Koellikerioides intestinalis (Yamaguti, 1970) (prevalence = 54.65%, abundance = 10.96) in the intestinal submucosa showed that the thin parasitic hindbody tegumentum was directly embedded in layers of connective tissue bands. Only a few cellular elements (lymphocytes, fibroblasts and fibrocytes) infiltrated the connective tissue capsule, which differed between the two didymozoid species in thickness, not in the type of filaments expressed. Cysts showed positive reaction to extracellular collagen as well as appearing positive for the cytoskeletal intermediate filaments vimentin and cytokeratin. [source] Identifying a molecular phenotype for bone marrow stromal cells with in vivo bone-forming capacityJOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2010Kenneth H Larsen Abstract The ability of bone marrow stromal cells (BMSCs) to differentiate into osteoblasts is being exploited in cell-based therapy for repair of bone defects. However, the phenotype of ex vivo cultured BMSCs predicting their bone-forming capacity is not known. Thus we employed DNA microarrays comparing two human bone marrow stromal cell (hBMSC) populations: One is capable of in vivo heterotopic bone formation (hBMSC-TERT+Bone), and the other is not (hBMSC-TERT,Bone). Compared with hBMSC-TERT,Bone, the hBMSC-TERT+Bone cells had an increased overrepresentation of extracellular matrix genes (17% versus 5%) and a larger percentage of genes with predicted SP3 transcription factor,binding sites in their promoter region (21% versus 8%). On the other hand, hBMSC-TERT,Bone cells expressed a larger number of immune-response-related genes (26% versus 8%). In order to test for the predictive value of these markers, we studied the correlation between their expression levels in six different hBMSC-derived clones and the ability to form bone in vivo. We found a significant correlation for decorin, lysyl oxidase-like 4, natriuretic peptide receptor C, and tetranectin. No significant positive correlation was found for canonical osteoblastic markers Runx2, alkaline phosphatase, collagen type I, osteopontin, and bone sialoprotein. Prospective isolation of four additional hBMSC clones based on their expression levels of the molecular markers correlated with their in vivo bone-formation ability. In conclusion, our data suggest an in vitro molecular signature predictive for hBMSCs' in vivo bone-formation ability. Identifying more of these predictive markers would be very useful in the quality control of osteoblastic cells before use in therapy. © 2010 American Society for Bone and Mineral Research [source] Regulation of Human Skeletal Stem Cells Differentiation by Dlk1/Pref-1JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2004Basem M Abdallah Abstract Dlk-1/Pref-1 was identified as a novel regulator of human skeletal stem cell differentiation. Dlk1/Pref-1 is expressed in bone and cultured osteoblasts, and its constitutive overexpression led to inhibition of osteoblast and adipocyte differentiation of human marrow stromal cells. Introduction: Molecular control of human mesenchymal stem cell (hMSC) differentiation into osteoblasts and adipocytes is not known. In this study, we examined the role of delta-like 1/preadipocyte factor-1 (Dlk1/Pref-1) in regulating the differentiation of hMSCs. Materials and Methods: As a model for hMSCs, we have stably transduced telomerase-immortalized hMSC (hMSC-TERT) with the full length of human Dlk1/Pref-1 cDNA and tested its effect on hMSC growth and differentiation into osteoblasts or adipocytes as assessed by cytochemical staining, FACS analysis, and real time PCR. Ex vivo calvaria organ cultures assay was used to confirm the in vitro effect of Dlk/Pref-1 on bone formation. Results: Dlk1/Pref-1 was found to be expressed in fetal and adult bone, hMSCs, and some osteoblastic cell lines. A retroviral vector containing the human Dlk1/Pref-1 cDNA was used to create a cell line (hMSC-dlk1) expressing high levels of Dlk1/Pref-1 protein. Overexpression of Dlk1/Pref-1 did not affect the proliferation rate of hMSC, but the ability to form mature adipocytes, mineralized matrix in vitro, and new bone formation in neonatal murine calvariae organ cultures was reduced. These effects were associated with inhibition of gene expression markers of late stages of adipocyte (adipocyte fatty acid-binding protein [aP2], peroxisome proliferator-activated receptor-gamma2 [PPAR,2], and adiponectin [APM1]) and osteoblast differentiation (alkaline phosphatase [ALP], collagen type I [Col1], and osteocalcin [OC]). Lineage commitment markers for adipocytes (adipocyte determination and differentiation factor ,1 [ADD1]) and osteoblasts (core binding factor/runt-related binding factor 2 [Cbfa1/Runx2]) were not affected. Conclusion: During hMSC differentiation, Dlk1/Pref-1 maintains the size of the bipotential progenitor cell pool by inhibiting the formation of mature osteoblasts and adipocytes. [source] Genetic and Environmental Determinants of Peak Bone Mass in Young Men and WomenJOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2002Fiona E. A. Mcguigan Ph.D. Abstract Peak bone mass is an important risk factor for the development of osteoporosis in later life. Previous work has suggested that genetic, intrauterine, and environmental factors all contribute to the regulation of bone mass, but the ways in which they interact with each other to do so remain poorly understood. In this study, we investigated the relationship between peak bone mass and polymorphisms of the vitamin D receptor (VDR), estrogen receptor (ER) ,, and collagen type I,1 (COLIA1) genes in relation to other factors such as birth weight, lifestyle diet, and exercise in a population-based cohort of 216 women and 244 men in their early 20s. Stepwise multiple regression analysis showed that body weight was the strongest predictor of bone mineral density (BMD) in women, accounting for 16.4% of the variance in spine BMD and 8.4% of the variance in femoral neck BMD. Other significant predictors were VDR genotype (3.8%) and carbohydrate intake (1.6%) at the spine and vitamin D intake (3.4%) and ER genotype (3.4%) at the femoral neck. Physical activity was the strongest predictor of BMD in men, accounting for 6.7% of the variance at the spine and 5.1% at the hip. Other significant predictors were body weight (5%) and ER PvuII genotype (2.8%) at the spine and weight (3.4%) and alcohol intake (2%) at the femoral neck. Birth weight was not a significant predictor of BMD at either site but COLIA1 genotype significantly predicted birth weight in women, accounting for 4.3% of the variance. We conclude that peak bone mass is regulated by an overlapping but distinct set of environmental and genetic influences that differ in men and women. However, much of the variance in BMD was unexplained by the variables studied here, which suggests that either most of the genes that regulate BMD remain to be discovered or major environmental influences on BMD exist that have not yet been identified. [source] Cross-Sectional Evaluation of Bone Metabolism in Men,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2001P. Szulc Abstract There are relatively few data concerning age-related changes of bone turnover in men. The aim of the study was to evaluate age-related changes of the levels of serum and urinary biochemical markers of bone metabolism in a large cohort of 934 men aged 19,85 years and to investigate their association with bone mineral density (BMD). Bone formation was evaluated using serum levels of osteocalcin (OC), bone alkaline phosphatase (BAP), and N-terminal extension propeptide of type I collagen (PINP). Bone resorption was evaluated by measurement of urinary excretion of ,-isomerized C-terminal telopeptide of collagen type I (,-CTX) of free deoxypyridinoline (fDpyr) and total Dpyr (tDPyr) and of the serum level of ,-CTX. Levels of biochemical bone markers were very high in young men and decreased rapidly until the age of 40 years and then more slowly until 60 years of age. After the age of 60 years, markers of bone formation remained stable while resorption markers showed a moderate and variable increase with aging. Serum and urinary ,-CTX levels were elevated only in about 5% of elderly men. The age-related increase of urinary excretion of tDpyr and of its free and peptide-bound fractions was related to the presence of elevated levels in a subgroup of about 15% of elderly men. Before 60 years of age, levels of biochemical bone markers were not correlated with BMD, whereas after 60 years of age, they were correlated negatively with BMD. After adjustment for age and body weight, BMD in men with the highest levels of biochemical bone markers (i.e., in the upper quartile) was 1.8,12.5% (i.e., 0.25,0.89 SD) lower than in men with levels of biochemical bone markers in the lowest quartile. In conclusion, bone turnover in men is high in young adults and decreases to reach a nadir at 55,60 years of age. After the age of 60 years, bone resorption markers,but not bone formation markers,increase in some men and are associated with lower BMD, suggesting that this imbalance is responsible for increasing bone loss in elderly men. [source] Enhanced cartilage tissue engineering by sequential exposure of chondrocytes to FGF-2 during 2D expansion and BMP-2 during 3D cultivationJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2001Ivan Martin Abstract Bovine calf articular chondrocytes, either primary or expanded in monolayers (2D) with or without 5 ng/ml fibroblast growth factor-2 (FGF-2), were cultured on three-dimensional (3D) biodegradable polyglycolic acid (PGA) scaffolds with or without 10 ng/ml bone morphogenetic protein-2 (BMP-2). Chondrocytes expanded without FGF-2 exhibited high intensity immunostaining for smooth muscle ,-actin (SMA) and collagen type I and induced shrinkage of the PGA scaffold, thus resembling contractile fibroblasts. Chondrocytes expanded in the presence of FGF-2 and cultured 6 weeks on PGA scaffolds yielded engineered cartilage with 3.7-fold higher cell number, 4.2-fold higher wet weight, and 2.8-fold higher wet weight glycosaminoglycan (GAG) fraction than chondrocytes expanded without FGF-2. Chondrocytes expanded with FGF-2 and cultured on PGA scaffolds in the presence of BMP-2 for 6 weeks yielded engineered cartilage with similar cellularity and size, 1.5-fold higher wet weight GAG fraction, and more homogenous GAG distribution than the corresponding engineered cartilage cultured without BMP-2. The presence of BMP-2 during 3D culture had no apparent effect on primary chondrocytes or those expanded without FGF-2. In summary, the presence of FGF-2 during 2D expansion reduced chondrocyte expression of fibroblastic molecules and induced responsiveness to BMP-2 during 3D cultivation on PGA scaffolds. © 2001 Wiley-Liss, Inc. [source] Decorin transfection in human mesangial cells downregulates genes playing a role in the progression of fibrosisJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 4 2002Antonia Costacurta Abstract The proteoglycan decorin inhibits TGF-,; therefore, it could antagonize progression of fibrotic diseases associated with activation of TGF-,1. The effect of decorin transfection in human mesangial cells (HMCs) on the expression of genes related to kidney fibrosis was investigated. HMCs, isolated from glomeruli of healthy portions of human kidneys removed due to carcinoma, were histochemically typed. Decorin cDNA cloned in a eukaryotic expression vector was transfected into HMCs. Gene expression of fibrogenetic cytokines and fibrotic proteins TGF-,1, PDGF-,, ,1 collagen type IV, ,1 collagen type I, fibronectin, and tenascin was analyzed, by reverse transcription polymerase chain reaction (RT-PCR), 24 hr after transfection. Immunoblotting analysis of protein extracts using anti-decorin IgG, revealed a positive signal of about 52 MDa, corresponding to the molecular weight of decorin, in cultures transfected with the decorin gene. Decorin mRNA increased about 12 times in cultures transfected with the construct pCR3.1-Deco. Cells with increased decorin synthesis showed a 61% decrease of TGF-,1 mRNA, a 71% reduction of ,1 collagen type IV mRNA, and a 29% reduction of fibronectin mRNA. This study is the first to investigate decorin transfection into human mesangial cells, and supports the use of the decorin gene to control the progression of glomerular and interstitial fibrosis in kidney diseases. © 2002 Wiley-Liss, Inc. [source] An immunohistological study of anhydrous topical ascorbic acid compositions on ex vivo human skinJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2006Geoffrey K Heber MBBS Summary Background, Ascorbic acid has numerous essential and beneficial functions in normal and photoaged skin. Ionisation of ascorbic acid in aqueous topical formulations leads to oxidative degradation. Ascorbic acid in an anhydrous vehicle would inherently have greater stability. Objective, The objective of this study was to observe the effects of two anhydrous formulations containing microfine particles of ascorbic acid on neocollagenesis and cytokeratin production in ex vivo human skin. Methods, Vitamin C preparations were applied topically onto the surface of freshly excised human abdominal skin. Following an exposure time of 48 h with appropriate controls, skin discs were cut into sections, placed on slides and assessed using immunohistochemical (antibodies: collagen type I, III, cytokeratin) staining. Analysis was performed using microscopy and descriptive rating. Results, Both formulations resulted in increased production of collagen types I and III and cytokeratin. Conclusion, The application of anhydrous formulations containing microfine particles of ascorbic acid to ex vivo human skin in this study resulted in neocollagenesis and increased production of cytokeratin. This approach appears to enable biological effects of ascorbic acid in the skin using a vehicle which would provide it greater stability than an aqueous vehicle. [source] Effects of antisense oligodeoxynucleotide to type I collagen gene on hypertrophic scars in the transplanted nude mouse modelJOURNAL OF CUTANEOUS PATHOLOGY, Issue 11 2009Julin Xie Background:, Antisense nucleic acids are effective in inhibiting harmful or uncontrolled gene expression. We had previously proved that the antisense DNA to type I collagen could effectively inhibit the synthesis of collagen type I in cultured hypertrophic scar fibroblasts, suggesting a potential role in anti-scarring, but there are no published reports of its effect on scar in the transplanted nude mouse model. Aims:, To investigate the effects of antisense oligodeoxynucleotide (ASODN) to type I collagen gene on hypertrophic scars in the transplanted nude mouse model and clarify the potential of ASODN for the treatment of scars. Methods:, The nude mouse model of hypertrophic scar was created and subjected to daily injections with ASODN and LipofectamineÔ for 2 ,4 or 6 weeks. We then examined the scars for changes in histopathological characteristics. The effects of ASODN on type I collagen gene expression were examined by reverse transcription-polymerase chain reaction and Western blots. Results:, The ASODN could remarkably alleviate the scar in the nude mouse model and consistently inhibit type I collagen gene expression at both the mRNA and protein levels. Conclusion:, ASODN was effective in downregulating type I collagen gene expression and could prove to be useful in the treatment of scars. [source] Vulnerable Plaque: The Pathology of Unstable Coronary LesionsJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 6 2002RENU VIRMANI M.D. Vulnerable plagues have been defined as precursors to lesions that rupture. However, coronary thrombosis may occur from other lesions like plaque erosion and calcified nodules, although to a lesser frequency than rupture. Therefore, the definition of vulnerable plaque should be all-inclusive. Using descriptive terminology, the authors define the precursor lesion of plaque rupture as "thin-cap fibroatheroma" (TCFA). Morphologically, TCFAs have a necrotic core with an overlying thin fibrous cap (< 65 mm) consisting of collagen type I, which is infiltrated by macrophages. These lesions are most frequent in the coronary tree of patients dying with acme myocardial infarction and least common in those with plaque erosion. TCFAs are more common in patients with high serum total cholesterol (TC) and a high TC to high density cholesterol ratio, in women >50 years, and in those patients with elevated levels of high sensitivity C-reactive protein. TCFAs are mostly found in the proximal left anterior descending coronary arteries and less commonly in the proximal right or the proximal left circumflex coronary arteries. In TCFAs, necrotic core length is , 2,17 mm (mean 8 mm) and the underlying cross-sectional luminal narrowing in over 75% of cases is < 75% (< 50% diameter stenosis). The area of the necrotic core in at least 75% of cases is ,3 mm2. Clinical studies of TCFAs are limited as angiography and intravascular ultrasound (TVUS) catheters cannot precisely identify these lesions. Newer catheters and other techniques are at various stages of development and will play a significant role in the understanding of plaque progression and the development of symptomatic coronary artery disease. [source] Rotating three-dimensional dynamic culture of adult human bone marrow-derived cells for tissue engineering of hyaline cartilageJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2009Shinsuke Sakai Abstract The method of constructing cartilage tissue from bone marrow-derived cells in vitro is considered a valuable technique for hyaline cartilage regenerative medicine. Using a rotating wall vessel (RWV) bioreactor developed in a NASA space experiment, we attempted to efficiently construct hyaline cartilage tissue from human bone marrow-derived cells without using a scaffold. Bone marrow aspirates were obtained from the iliac crest of nine patients during orthopedic operation. After their proliferation in monolayer culture, the adherent cells were cultured in the RWV bioreactor with chondrogenic medium for 2 weeks. Cells from the same source were cultured in pellet culture as controls. Histological and immunohistological evaluations (collagen type I and II) and quantification of glycosaminoglycan were performed on formed tissues and compared. The engineered constructs obtained using the RWV bioreactor showed strong features of hyaline cartilage in terms of their morphology as determined by histological and immunohistological evaluations. The glycosaminoglycan contents per µg DNA of the tissues were 10.01,±,3.49 µg/µg DNA in the case of the RWV bioreactor and 6.27,±,3.41 µg/µg DNA in the case of the pellet culture, and their difference was significant. The RWV bioreactor could provide an excellent environment for three-dimensional cartilage tissue architecture that can promote the chondrogenic differentiation of adult human bone marrow-derived cells. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 517,521, 2009 [source] Quantitative analysis of gene expression in human articular chondrocytes assigned for autologous implantationJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2008Ariana Barli Abstract Autologous chondrocyte implantation (ACI) relies on the implantation of in vitro expanded cells. The aim was to study the dedifferentiation of human articular chondrocytes under different cultivating conditions [days 0,10 in the primary culture (P0); passages in a monolayer from P0 to P3; monolayer vs. alginate and monolayer vs. alginate/agarose hydrogels] using real-time PCR analysis. The relative gene expressions for collagen type I and II, aggrecan and versican were quantified and the corresponding differentiation indexes (Col2/Col1, Agr/Ver) were calculated. The values of both differentiation indexes decreased exponentially with time in the P0 monolayer culture, and continued with a significant decrease over the subsequent monolayer passages. On the contrary, the chondrocytes seeded in either of the hydrogels significantly increased the indexes compared to their parallel monolayer cultures. These results indicate that alginate and alginate/agarose hydrogels offer an appropriate environment for human articular chondrocytes to redifferentiate after being expanded in vitro. Therefore the three-dimensional (3D) hydrogel chondrocyte cultures present not only surgical, but also biological advantage over the classic suspension,periosteum chondrocyte implantation. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:847,853, 2008 [source] Differentiation of human mesenchymal stem cells and articular chondrocytes: Analysis of chondrogenic potential and expression pattern of differentiation-related transcription factorsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2007Camilla Karlsson Abstract Mesenchymal stem cells (MSCs) are a candidate for replacing chondrocytes in cell-based repair of cartilage lesions. However, it has not been clarified if these cells can acquire the hyaline phenotype, and whether chondrocytes and MSCs show the same expression patterns of critical control genes in development. In order to study this, articular chondrocytes and iliac crest derived MSCs were allowed to differentiate in pellet mass cultures. Gene expression of markers for the cartilage phenotype, helix-loop-helix (HLH) transcription factors, and chondrogenic transcription factors were analyzed by real-time PCR. Matrix production was assayed using biochemical analysis for hydroxyproline, glycosaminoglycans, and immunohistochemistry for collagen types I and II. Significantly decreased expression of collagen type I was accompanied by increased expression of collagen types IIA and IIB during differentiation of chondrocytes, indicating differentiation towards a hyaline phenotype. Chondrogenesis in MSCs on the other hand resulted in up-regulation of collagen types I, IIA, IIB, and X, demonstrating differentiation towards cartilage of a mixed phenotype. Expression of HES1 increased significantly during chondrogenesis in chondrocytes while expression in MSCs was maintained at a low level. The HLH gene HES5 on the other hand was only detected in chondrocytes. Expression of ID1 decreased significantly in chondrocytes while the opposite was seen in MSCs. These findings suggest that chondrocytes and MSCs differentiated and formed different subtypes of cartilage, the hyaline and a mixed cartilage phenotype, respectively. Differentially regulated HLH genes indicated the possibility for HLH proteins in regulating chondrogenic differentiation. This information is important to understand the potential use of MSCs in cartilage repair. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:152,163, 2007 [source] Achilles Detachment in Rat and Stable Gastric Pentadecapeptide BPC 157: Promoted Tendon-to-Bone Healing and Opposed Corticosteroid AggravationJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2006Andrija Krivic Abstract Stable gastric pentadecapeptide BPC 157 (BPC 157, as an antiulcer agent in clinical trials for inflammatory bowel disease; PLD-116, PL 14736, Pliva, no toxicity reported) alone (without carrier) ameliorates healing of tendon and bone, respectively, as well as other tissues. Thereby, we focus on Achilles tendon-to-bone healing: tendon to bone could not be healed spontaneously, but it was recovered by this peptide. After the rat's Achilles tendon was sharply transected from calcaneal bone, agents [BPC 157 (10 µg, 10 ng, 10 pg), 6,-methylprednisolone (1 mg), 0.9% NaCl (5 mL)] were given alone or in combination [/kg body weight (b.w.) intraperitoneally, once time daily, first 30-min after surgery, last 24 h before analysis]. Tested at days 1, 4, 7, 10, 14, and 21 after Achilles detachment, BPC 157 improves healing functionally [Achilles functional index (AFI) values substantially increased], biomechanically (load to failure, stiffness, and Young elasticity modulus significantly increased), macro/microscopically, immunohistochemistry (better organization of collagen fibers, and advanced vascular appearance, more collagen type I). 6,-Methylprednisolone consistently aggravates the healing, while BPC 157 substantially reduces 6,-methylprednisolone healing aggravation. Thus, direct tendon-to-bone healing using stabile nontoxic peptide BPC 157 without a carrier might successfully exchange the present reconstructive surgical methods. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Multilineage mesenchymal differentiation potential of human trabecular bone-derived cellsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2002Ulrich Nöth Abstract Explant cultures of adult human trabecular bone fragments give rise to osteoblastic cells, that are known to express osteoblast-related genes and mineralize extracellular matrix. These osteoblastic cells have also been shown to undergo adipogenesis in vitro and chondrogenesis in vivo. Here we report the in vitro developmental potential of adult human osteoblastic cells (hOB) derived from explant cultures of collagenase-pretreated trabecular bone fragments. In addition to osteogenic and adipogenic differentiation, these cells are capable of chondrogenic differentiation in vitro in a manner similar to adult human bone marrow-derived mesenchymal progenitor cells. High-density pellet cultures of hOB maintained in chemically defined serum-free medium, supplemented with transforming growth factor-,1, were composed of morphologically distinct, chondrocyte-like cells expressing mRNA transcripts of collagen types II, IX and X, and aggrecan. The cells within the high-density pellet cultures were surrounded by a sulfated prote-oglycan-rich extracellular matrix that immunostained for collagen type II and proteoglycan link protein. Osteogenic differentiation of hOB was verified by an increased number of alkaline phosphatase-positive cells, that expressed osteoblast-related transcripts such as alkaline phosphatase, collagen type I, osteopontin and osteocalcin, and formed mineralized matrix in monolayer cultures treated with ascorbate, ,-glycerophosphate, and bone morphogenetic protein-2. Adipogenic differentiation of hOB was determined by the appearance of intracellular lipid droplets, and expression of adipocyte-specific genes, such as lipoprotein lipase and peroxisome proliferator-activated receptor ,2, in monolayer cultures treated with dexamethasone, indomethacin, insulin and 3-isobutyl-l-methylxanthine. Taken together, these results show that cells derived from collagenase-treated adult human trabecular bone fragments have the potential to differentiate into multiple mesenchymal lineages in vitro, indicating their developmental plasticity and suggesting their mesenchymal progenitor nature. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Effects of adenoviral-mediated coexpression of bone morphogenetic protein-7 and insulin-like growth factor-1 on human periodontal ligament cellsJOURNAL OF PERIODONTAL RESEARCH, Issue 4 2010L. Yang Yang L, Zhang Y, Dong R, Peng L, Liu X, Wang Y, Cheng X. Effects of adenoviral-mediated coexpression of bone morphogenetic protein-7 and insulin-like growth factor-1 on human periodontal ligament cells. J Periodont Res 2010; 45: 532,540. © 2010 John Wiley & Sons A/S Background and Objective:, Bone morphogenetic protein-7 (BMP-7) and insulin-like growth factor-1 (IGF-1) are important in periodontal reconstruction. However, their synergistic effect in periodontal regeneration by gene delivery has not been reported. In this study, gene delivery of these two growth factors to human periodontal ligament cells (hPDLCs) was examined for its effects on cell proliferation and differentiation. Material and Methods:, Recombinant adenoviruses containing both human BMP-7 and IGF-1 cDNA created by introducing the internal ribosome entry site (IRES) sequence were used to transfer the genes into hPDLCs. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell cycle analysis were used to observe their effects on cell proliferation, while alkaline phosphatase activity measurement, RT-PCR and in vivo tests were conducted to investigate their effects on cell differentiation. Results:, The proliferation of hPDLCs transduced by adenoviruses coexpressing BMP-7 and IGF-1 was suppressed while their differentiation ability was enhanced. There was a synergism of BMP-7 and IGF-1 in up-regulating alkaline phosphatase activity and mRNA levels of collagen type I and Runx2. Implantation in vivo with scaffolds illustrated that the transduced cells exhibited osteogenic differentiation and formed bone-like structures. Conclusion:, The combined delivery of BMP-7 and IGF-1 genes using an IRES-based strategy synergistically enhanced differentiation of hPDLCs. It is suggested that this could be a new potential method in gene therapy for periodontal reconstruction. [source] The effect of Emdogain® on the growth and differentiation of rat bone marrow cellsJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2006J. Van Den Dolder Background and Objective:, The major extracellular matrix (ECM) proteins in developing enamel can induce and maintain the formation and mineralization of other skeletal hard tissue, such as bone. Therefore, dental matrix proteins are ideal therapeutic agents when direct formation of functional bone is required for a successful clinical outcome. Emdogain® (EMD) consists of enamel matrix proteins which are known to stimulate bone formation. However, only a few studies in the literature have reported the effect of EMD on osteoblast-like cells in vitro. Material and Methods:, In this study, rat bone marrow cells, obtained from the femora of Wistar rats, were precultured for 7 d in osteogenic medium. Then, the cells were harvested and seeded in 24-well plates at a concentration of 20,000 cells/well. The wells were either precoated with 100 µg/ml EMD, or left uncoated. The seeded cells were cultured in osteogenic medium for 32 d and analysed for cell attachment (by using the Live and Dead assay), cell growth (by determining DNA content) and cell differentiation (by measuring alkaline phosphatase activity and calcium content, and by using scanning electron microscopy and the reverse transcription,polymerase chain reaction). Results:, The results showed that at the 4-h time point of the experiment, more cells were attached to EMD-negative wells, but this effect was no longer apparent at 24 h. DNA analysis revealed that both groups showed a similar linear trend of cell growth. No differences in alkaline phosphatase activity or calcium content were observed, and no differences in gene expression (osteocalcin, alkaline phosphatase and collagen type I) were found between the groups. Conclusion:, Based on our results, we conclude that EMD had no significant effect on the cell growth and differentiation of rat bone marrow cells. [source] Melatonin effect on bone metabolism in rats treated with methylprednisoloneJOURNAL OF PINEAL RESEARCH, Issue 4 2006Marta G. Ladizesky Abstract:, The present study was undertaken to examine the effect of melatonin (25 ,g/mL of drinking water, about 500 ,g/day) on a 10-wk long treatment of male rats with methylprednisolone (5 mg/kg s.c., 5 days/wk). Bone densitometry and mechanical properties, calcemia, phosphatemia and serum bone alkaline phosphatase activity and C-telopeptide fragments of collagen type I (CTX) were measured. Both melatonin and methylprednisolone decreased significantly body weight (BW) and the combination of both treatments resulted in the lowest BW values found. Consequently, all results were analyzed with BW as a covariate. Densitometrically, methylprednisolone augmented bone mineral content (BMC), bone area (BA) and bone mineral density (BMD) in the entire skeleton, BMC in cortical bone, and BMC and BMD in trabecular bone. Melatonin increased BMC and BA in whole skeleton and BMC and BMD in trabecular bone. For BMC and BA of whole skeleton, BMC of cortical bone, and BMC and BMD of trabecular bone, the combination of glucocorticoids and melatonin resulted in the highest values observed. Femoral weight of rats receiving methylprednisolone or melatonin increased significantly and both treatments summated to achieve the greatest effect. In femoral biomechanical testing, methylprednisolone augmented ultimate load and work to failure significantly. Rats receiving the combined treatment of methylprednisolone and melatonin showed the highest values of work to failure. The circulating levels of CTX, an index of bone resorption, decreased after methylprednisolone or melatonin, both treatments summating to achieve the lowest CTX values found. Serum calcium increased after methylprednisolone and serum phosphorus decreased after treatment with methylprednisolone or melatonin while serum bone alkaline phosphatase levels remained unchanged. The results are compatible with the view that low doses of methylprednisolone or melatonin decrease bone resorption and have a bone-protecting effect. [source] | ||||||||||||||||||||||||||||||||||