Pub Date : 2024-02-21eCollection Date: 2024-05-01DOI: 10.1093/jbmrpl/ziae021
Proapa Islam, John A Ice, Sanmi E Alake, Pelumi Adedigba, Bethany Hatter, Kara Robinson, Stephen L Clarke, Ashlee N Ford Versypt, Jerry Ritchey, Edralin A Lucas, Brenda J Smith
Targeting the gut-bone axis with probiotics and prebiotics is considered as a promising strategy to reduce the risk of osteoporosis. Gut-derived short chain fatty acids (SCFA) mediate the effects of probiotics on bone via Tregs, but it is not known whether prebiotics act through a similar mechanism. We investigated how 2 different prebiotics, tart cherry (TC) and fructooligosaccharide (FOS), affect bone, and whether Tregs are required for this response. Eight-wk-old C57BL/6 female mice were fed with diets supplemented with 10% w/w TC, FOS, or a control diet (Con; AIN-93M) diet, and they received an isotype control or CD25 Ab to suppress Tregs. The FOS diet increased BMC, density, and trabecular bone volume in the vertebra (~40%) and proximal tibia (~30%) compared to the TC and control diets (Con), irrespective of CD25 treatment. Both prebiotics increased (P < .01) fecal SCFAs, but the response was greater with FOS. To determine how FOS affected bone cells, we examined genes involved in osteoblast and osteoclast differentiation and activity as well as genes expressed by osteocytes. The FOS increased the expression of regulators of osteoblast differentiation (bone morphogenetic protein 2 [Bmp2], Wnt family member 10b [Wnt10b] and Osterix [Osx]) and type 1 collagen). Osteoclasts regulators were unaltered. The FOS also increased the expression of genes associated with osteocytes, including (Phex), matrix extracellular phosphoglycoprotein (Mepe), and dentin matrix acidic phosphoprotein 1 (Dmp-1). However, Sost, the gene that encodes for sclerostin was also increased by FOS as the number and density of osteocytes increased. These findings demonstrate that FOS has a greater effect on the bone mass and structure in young adult female mice than TC and that its influence on osteoblasts and osteocytes is not dependent on Tregs.
{"title":"Fructooligosaccharides act on the gut-bone axis to improve bone independent of Tregs and alter osteocytes in young adult C57BL/6 female mice.","authors":"Proapa Islam, John A Ice, Sanmi E Alake, Pelumi Adedigba, Bethany Hatter, Kara Robinson, Stephen L Clarke, Ashlee N Ford Versypt, Jerry Ritchey, Edralin A Lucas, Brenda J Smith","doi":"10.1093/jbmrpl/ziae021","DOIUrl":"10.1093/jbmrpl/ziae021","url":null,"abstract":"<p><p>Targeting the gut-bone axis with probiotics and prebiotics is considered as a promising strategy to reduce the risk of osteoporosis. Gut-derived short chain fatty acids (SCFA) mediate the effects of probiotics on bone via Tregs, but it is not known whether prebiotics act through a similar mechanism. We investigated how 2 different prebiotics, tart cherry (TC) and fructooligosaccharide (FOS), affect bone, and whether Tregs are required for this response. Eight-wk-old C57BL/6 female mice were fed with diets supplemented with 10% w/w TC, FOS, or a control diet (Con; AIN-93M) diet, and they received an isotype control or CD25 Ab to suppress Tregs. The FOS diet increased BMC, density, and trabecular bone volume in the vertebra (~40%) and proximal tibia (~30%) compared to the TC and control diets (Con), irrespective of CD25 treatment. Both prebiotics increased (<i>P <</i> .01) fecal SCFAs, but the response was greater with FOS. To determine how FOS affected bone cells, we examined genes involved in osteoblast and osteoclast differentiation and activity as well as genes expressed by osteocytes. The FOS increased the expression of regulators of osteoblast differentiation (bone morphogenetic protein 2 [Bmp2], Wnt family member 10b [Wnt10b] and Osterix [Osx]) and type 1 collagen). Osteoclasts regulators were unaltered. The FOS also increased the expression of genes associated with osteocytes, including (Phex), matrix extracellular phosphoglycoprotein (Mepe), and dentin matrix acidic phosphoprotein 1 (Dmp-1). However, <i>Sost</i>, the gene that encodes for sclerostin was also increased by FOS as the number and density of osteocytes increased. These findings demonstrate that FOS has a greater effect on the bone mass and structure in young adult female mice than TC and that its influence on osteoblasts and osteocytes is not dependent on Tregs.</p>","PeriodicalId":14611,"journal":{"name":"JBMR Plus","volume":"8 5","pages":"ziae021"},"PeriodicalIF":3.8,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10982850/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140335593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-30eCollection Date: 2024-04-01DOI: 10.1093/jbmrpl/ziae013
Karl J Jepsen, Erin M R Bigelow, Robert W Goulet, Bonnie T Nolan, Michael A Casden, Kathryn Kennedy, Samantha Hertz, Chandan Kadur, Gregory A Clines, Aleda M Leis, Carrie A Karvonen-Gutierrez, Todd L Bredbenner
Hip areal BMD (aBMD) is widely used to identify individuals with increased fracture risk. Low aBMD indicates low strength, but this association differs by sex with men showing greater strength for a given aBMD than women. To better understand the structural basis giving rise to this sex-specific discrepancy, cadaveric proximal femurs from White female and male donors were imaged using nano-CT and loaded in a sideways fall configuration to assess strength. FN pseudoDXA images were generated to identify associations among structure, aBMD, and strength that differ by sex. Strength correlated significantly with pseudoDXA aBMD for females (R2 = 0.468, P < .001) and males (R2 = 0.393, P < .001), but the elevations (y-intercepts) of the linear regressions differed between sexes (P < .001). Male proximal femurs were 1045 N stronger than females for a given pseudoDXA aBMD. However, strength correlated with pseudoDXA BMC for females (R2 = 0.433, P < .001) and males (R2 = 0.443, P < .001) but without significant slope (P = .431) or elevation (P = .058) differences. Dividing pseudoDXA BMC by FN-width, total cross-sectional area, or FN-volume led to significantly different associations between strength and the size-adjusted BMC measures for women and men. Three structural differences were identified that differentially affected aBMD and strength for women and men: First, men had more bone mass per unit volume than women; second, different cross-sectional shapes resulted in larger proportions of bone mass orthogonal to the DXA image for men than women; and third, men and women had different proportions of cortical and trabecular bone relative to BMC. Thus, the proximal femurs of women were not smaller versions of men but were constructed in fundamentally different manners. Dividing BMC by a bone size measure was responsible for the sex-specific associations between hip aBMD and strength. Thus, a new approach for adjusting measures of bone mass for bone size and stature is warranted.
{"title":"Structural differences contributing to sex-specific associations between FN BMD and whole-bone strength for adult White women and men.","authors":"Karl J Jepsen, Erin M R Bigelow, Robert W Goulet, Bonnie T Nolan, Michael A Casden, Kathryn Kennedy, Samantha Hertz, Chandan Kadur, Gregory A Clines, Aleda M Leis, Carrie A Karvonen-Gutierrez, Todd L Bredbenner","doi":"10.1093/jbmrpl/ziae013","DOIUrl":"10.1093/jbmrpl/ziae013","url":null,"abstract":"<p><p>Hip areal BMD (aBMD) is widely used to identify individuals with increased fracture risk. Low aBMD indicates low strength, but this association differs by sex with men showing greater strength for a given aBMD than women. To better understand the structural basis giving rise to this sex-specific discrepancy, cadaveric proximal femurs from White female and male donors were imaged using nano-CT and loaded in a sideways fall configuration to assess strength. FN pseudoDXA images were generated to identify associations among structure, aBMD, and strength that differ by sex. Strength correlated significantly with pseudoDXA aBMD for females (<i>R</i><sup>2</sup> = 0.468, <i>P</i> < .001) and males (<i>R</i><sup>2</sup> = 0.393, <i>P</i> < .001), but the elevations (<i>y</i>-intercepts) of the linear regressions differed between sexes (<i>P</i> < .001). Male proximal femurs were 1045 N stronger than females for a given pseudoDXA aBMD. However, strength correlated with pseudoDXA BMC for females (<i>R</i><sup>2</sup> = 0.433, <i>P</i> < .001) and males (<i>R</i><sup>2</sup> = 0.443, <i>P</i> < .001) but without significant slope (<i>P</i> = .431) or elevation (<i>P</i> = .058) differences. Dividing pseudoDXA BMC by FN-width, total cross-sectional area, or FN-volume led to significantly different associations between strength and the size-adjusted BMC measures for women and men. Three structural differences were identified that differentially affected aBMD and strength for women and men: First, men had more bone mass per unit volume than women; second, different cross-sectional shapes resulted in larger proportions of bone mass orthogonal to the DXA image for men than women; and third, men and women had different proportions of cortical and trabecular bone relative to BMC. Thus, the proximal femurs of women were not smaller versions of men but were constructed in fundamentally different manners. Dividing BMC by a bone size measure was responsible for the sex-specific associations between hip aBMD and strength. Thus, a new approach for adjusting measures of bone mass for bone size and stature is warranted.</p>","PeriodicalId":14611,"journal":{"name":"JBMR Plus","volume":"8 4","pages":"ziae013"},"PeriodicalIF":3.4,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10958990/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140206918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-27eCollection Date: 2024-02-01DOI: 10.1093/jbmrpl/ziae009
Ruban Dhaliwal, David Kendler, Kenneth Saag, Steven W Ing, Andrea Singer, Robert A Adler, Leny Pearman, Yamei Wang, Bruce Mitlak
Osteoporosis in men is an underappreciated public health issue, accounting for approximately 30% of the societal burden of osteoporosis. Although the prevalence of osteoporosis in men is lower, fracture-related morbidity and mortality rates exceed those of women. Abaloparatide is a synthetic, 34-amino acid peptide with homology to human parathyroid hormone-related protein (PTHrP), which favors bone formation by selective activation of PTH receptor type 1. In the Abaloparatide for the Treatment of Men With Osteoporosis (ATOM; NCT03512262) trial, 228 men with primary or hypogonadism-associated osteoporosis were randomized to receive subcutaneous injections of abaloparatide 80 μg or placebo. Abaloparatide significantly improved LS, TH, and FN BMD when compared with placebo. In this prespecified analysis, the proportion of men with a percent change from baseline of >0%, >3%, and > 6% in BMD at the LS, TH, and FN at 3, 6, and 12 mo and/or a shift in T-score category (based on LS and TH T-scores) at 12 mo was compared between the abaloparatide and placebo groups in ATOM. There were significantly more men with a BMD gain of >3% at all 3 anatomical sites in the abaloparatide than placebo group at month 6 (18/122 [14.8%] vs 1/70 [1.4%], P = .002) and at month 12 (38/119 [31.9%] vs 1/66 [1.5%], P < .0001). At month 3, more men treated with abaloparatide than placebo had a > 3% BMD increase at the LS (82/134 [61.2%] vs 21/68 [30.9%], P < .0001). A greater proportion of men treated with abaloparatide had an improvement in T-score category from osteoporosis to low BMD or normal when compared with placebo. In conclusion, use of abaloparatide compared with placebo for 12 mo resulted in significant and rapid improvements in BMD in men with osteoporosis from the ATOM study.
男性骨质疏松症是一个未得到充分重视的公共健康问题，约占骨质疏松症社会负担的 30%。虽然男性骨质疏松症的发病率较低，但与骨折相关的发病率和死亡率却超过了女性。阿巴帕肽是一种合成的 34 氨基酸肽，与人类甲状旁腺激素相关蛋白（PTHrP）具有同源性，可通过选择性激活 PTH 受体 1 型来促进骨形成。在阿巴拉帕肽治疗男性骨质疏松症（ATOM；NCT03512262）试验中，228名患有原发性或性腺功能低下相关性骨质疏松症的男性被随机分配接受阿巴拉帕肽80微克或安慰剂的皮下注射。与安慰剂相比，阿巴拉帕肽能明显改善LS、TH和FN BMD。在这项预设分析中，比较了 ATOM 中阿巴帕肽组与安慰剂组之间在 3、6 和 12 个月时 LS、TH 和 FN BMD 与基线相比变化百分比大于 0%、大于 3% 和大于 6% 的男性比例，以及/或在 12 个月时 T 评分类别发生变化（基于 LS 和 TH T 评分）的男性比例。在第 6 个月时（18/122 [14.8%] vs 1/70 [1.4%]，P = .002）和第 12 个月时（38/119 [31.9%] vs 1/66 [1.5%]，P 3%），阿巴帕肽组在所有 3 个解剖部位的 BMD 增幅均大于安慰剂组的男性人数（82/134 [61.2%] vs 21/68 [30.9%]，P = .002）。
{"title":"Response rates for lumbar spine, total hip, and femoral neck bone mineral density in men treated with abaloparatide: results from the ATOM study.","authors":"Ruban Dhaliwal, David Kendler, Kenneth Saag, Steven W Ing, Andrea Singer, Robert A Adler, Leny Pearman, Yamei Wang, Bruce Mitlak","doi":"10.1093/jbmrpl/ziae009","DOIUrl":"https://doi.org/10.1093/jbmrpl/ziae009","url":null,"abstract":"<p><p>Osteoporosis in men is an underappreciated public health issue, accounting for approximately 30% of the societal burden of osteoporosis. Although the prevalence of osteoporosis in men is lower, fracture-related morbidity and mortality rates exceed those of women. Abaloparatide is a synthetic, 34-amino acid peptide with homology to human parathyroid hormone-related protein (PTHrP), which favors bone formation by selective activation of PTH receptor type 1. In the Abaloparatide for the Treatment of Men With Osteoporosis (ATOM; NCT03512262) trial, 228 men with primary or hypogonadism-associated osteoporosis were randomized to receive subcutaneous injections of abaloparatide 80 μg or placebo. Abaloparatide significantly improved LS, TH, and FN BMD when compared with placebo. In this prespecified analysis, the proportion of men with a percent change from baseline of >0%, >3%, and > 6% in BMD at the LS, TH, and FN at 3, 6, and 12 mo and/or a shift in T-score category (based on LS and TH T-scores) at 12 mo was compared between the abaloparatide and placebo groups in ATOM. There were significantly more men with a BMD gain of >3% at all 3 anatomical sites in the abaloparatide than placebo group at month 6 (18/122 [14.8%] vs 1/70 [1.4%], <i>P</i> = .002) and at month 12 (38/119 [31.9%] vs 1/66 [1.5%], <i>P</i> < .0001). At month 3, more men treated with abaloparatide than placebo had a > 3% BMD increase at the LS (82/134 [61.2%] vs 21/68 [30.9%], <i>P</i> < .0001). A greater proportion of men treated with abaloparatide had an improvement in T-score category from osteoporosis to low BMD or normal when compared with placebo. In conclusion, use of abaloparatide compared with placebo for 12 mo resulted in significant and rapid improvements in BMD in men with osteoporosis from the ATOM study.</p>","PeriodicalId":14611,"journal":{"name":"JBMR Plus","volume":"8 2","pages":"ziae009"},"PeriodicalIF":3.8,"publicationDate":"2024-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10945712/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140174719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Beatriz Bermudez, Kenna Brown, G. Vahidi, Ana C F Ruble, Chelsea M Heveran, Cheryl L Ackert-Bicknell, Vanessa Sherk
Western diets are becoming increasingly common around the world. Western diets have high omega 6 (ω-6) and omega 3 (ω-3) fatty acids and are linked to bone loss in humans and animals. Dietary fats are not created equal; therefore, it is vital to understand the effects of specific dietary fats on bone. We aimed to determine how altering the endogenous ratios of ω-6:ω-3 fatty acids impacts bone accrual, strength, and fracture toughness. To accomplish this, we used the Fat-1 transgenic mice, which carry a gene responsible for encoding an ω-3 fatty acid desaturase that converts ω-6 to ω-3 fatty acids. Male and female Fat-1 positive mice (Fat-1) and Fat-1 negative littermates (WT) were given either a high-fat diet (HFD) or low-fat diet (LFD) at 4 weeks of age for 16 weeks. The Fat-1 transgene reduced fracture toughness in males. Additionally, male bone mineral density (BMD), measured from dual-energy x-ray absorptiometry (DXA), decreased over the diet duration for HFD mice. In males, neither HFD feeding nor the presence of the Fat-1 transgene impacted cortical geometry, trabecular architecture, or whole-bone flexural properties, as detected by main group effects. In females, Fat-1-LFD mice experienced increases in BMD compared to WT-LFD mice, however, cortical area, distal femur trabecular thickness, and cortical stiffness were reduced in Fat-1 mice compared to pooled WT controls. However, reductions in stiffness were caused by a decrease in bone size and were not driven by changes in material properties. Together, these results demonstrate that the endogenous ω-6:ω-3 fatty acid ratio influences bone material properties in a sex-dependent manner. In addition, Fat-1 mediated fatty acid conversion was not able to mitigate the adverse effects of HFD on bone strength and accrual.
{"title":"Sex-specific effects of Fat-1 transgene on bone material properties, size, and shape in mice","authors":"Beatriz Bermudez, Kenna Brown, G. Vahidi, Ana C F Ruble, Chelsea M Heveran, Cheryl L Ackert-Bicknell, Vanessa Sherk","doi":"10.1093/jbmrpl/ziad011","DOIUrl":"https://doi.org/10.1093/jbmrpl/ziad011","url":null,"abstract":"\u0000 Western diets are becoming increasingly common around the world. Western diets have high omega 6 (ω-6) and omega 3 (ω-3) fatty acids and are linked to bone loss in humans and animals. Dietary fats are not created equal; therefore, it is vital to understand the effects of specific dietary fats on bone. We aimed to determine how altering the endogenous ratios of ω-6:ω-3 fatty acids impacts bone accrual, strength, and fracture toughness. To accomplish this, we used the Fat-1 transgenic mice, which carry a gene responsible for encoding an ω-3 fatty acid desaturase that converts ω-6 to ω-3 fatty acids. Male and female Fat-1 positive mice (Fat-1) and Fat-1 negative littermates (WT) were given either a high-fat diet (HFD) or low-fat diet (LFD) at 4 weeks of age for 16 weeks. The Fat-1 transgene reduced fracture toughness in males. Additionally, male bone mineral density (BMD), measured from dual-energy x-ray absorptiometry (DXA), decreased over the diet duration for HFD mice. In males, neither HFD feeding nor the presence of the Fat-1 transgene impacted cortical geometry, trabecular architecture, or whole-bone flexural properties, as detected by main group effects. In females, Fat-1-LFD mice experienced increases in BMD compared to WT-LFD mice, however, cortical area, distal femur trabecular thickness, and cortical stiffness were reduced in Fat-1 mice compared to pooled WT controls. However, reductions in stiffness were caused by a decrease in bone size and were not driven by changes in material properties. Together, these results demonstrate that the endogenous ω-6:ω-3 fatty acid ratio influences bone material properties in a sex-dependent manner. In addition, Fat-1 mediated fatty acid conversion was not able to mitigate the adverse effects of HFD on bone strength and accrual.","PeriodicalId":14611,"journal":{"name":"JBMR Plus","volume":"8 46","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139440019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Madison M Kelly, Karan Sharma, Christian S. Wright, Xin Yi, Perla C. Reyes Fernandez, Aaron T Gegg, Taylor A Gorrell, Megan L. Noonan, A. Baghdady, Jacob A Sieger, Annette C Dolphin, Stuart J Warden, Padmini J. Deosthale, Lilian I Plotkin, Uma Sankar, J. Hum, A. Robling, M. Farach-Carson, William R. Thompson
Voltage sensitive calcium channels (VSCCs) influence bone structure and function, including anabolic responses to mechanical loading. While the pore-forming (α1) subunit of VSCCs allows Ca2+ influx, auxiliary subunits regulate the biophysical properties of the pore. The α2δ1 subunit influences gating kinetics of the α1 pore and enables mechanically induced signaling in osteocytes; however, the skeletal function of α2δ1 in vivo remains unknown. In this work, we examined the skeletal consequences of deleting Cacna2d1, the gene encoding α2δ1. Dual energy X-ray absorptiometry (DEXA) and microcomputed tomography (μCT) imaging demonstrated that deletion of α2δ1 diminished bone mineral content and density in both male and female C57BL/6 mice. Structural differences manifested in both trabecular and cortical bone for males, while the absence of α2δ1 affected only cortical bone in female mice. Deletion of α2δ1 impaired skeletal mechanical properties in both sexes, as measured by three-point bending to failure. While no changes in osteoblast number or activity were found for either sex, male mice displayed a significant increase in osteoclast number, accompanied by increased eroded bone surface and upregulation of genes that regulate osteoclast differentiation. Deletion of α2δ1 also rendered the skeleton insensitive to exogenous mechanical loading in males. While previous work demonstrates that VSCCs are essential for anabolic responses to mechanical loading, the mechanism by which these channels sense and respond to force remained unclear. Our data demonstrate that the α2δ1 auxiliary VSCC subunit functions to maintain baseline bone mass and strength through regulation of osteoclast activity, and also provides skeletal mechanotransduction in male mice. These data reveal a molecular player in our understanding of the mechanisms by which VSCCs influence skeletal adaptation.
{"title":"Loss of the auxiliary α2δ1 voltage sensitive Calcium Channel subunit impairs bone formation and anabolic responses to mechanical loading","authors":"Madison M Kelly, Karan Sharma, Christian S. Wright, Xin Yi, Perla C. Reyes Fernandez, Aaron T Gegg, Taylor A Gorrell, Megan L. Noonan, A. Baghdady, Jacob A Sieger, Annette C Dolphin, Stuart J Warden, Padmini J. Deosthale, Lilian I Plotkin, Uma Sankar, J. Hum, A. Robling, M. Farach-Carson, William R. Thompson","doi":"10.1093/jbmrpl/ziad008","DOIUrl":"https://doi.org/10.1093/jbmrpl/ziad008","url":null,"abstract":"\u0000 Voltage sensitive calcium channels (VSCCs) influence bone structure and function, including anabolic responses to mechanical loading. While the pore-forming (α1) subunit of VSCCs allows Ca2+ influx, auxiliary subunits regulate the biophysical properties of the pore. The α2δ1 subunit influences gating kinetics of the α1 pore and enables mechanically induced signaling in osteocytes; however, the skeletal function of α2δ1 in vivo remains unknown. In this work, we examined the skeletal consequences of deleting Cacna2d1, the gene encoding α2δ1. Dual energy X-ray absorptiometry (DEXA) and microcomputed tomography (μCT) imaging demonstrated that deletion of α2δ1 diminished bone mineral content and density in both male and female C57BL/6 mice. Structural differences manifested in both trabecular and cortical bone for males, while the absence of α2δ1 affected only cortical bone in female mice. Deletion of α2δ1 impaired skeletal mechanical properties in both sexes, as measured by three-point bending to failure. While no changes in osteoblast number or activity were found for either sex, male mice displayed a significant increase in osteoclast number, accompanied by increased eroded bone surface and upregulation of genes that regulate osteoclast differentiation. Deletion of α2δ1 also rendered the skeleton insensitive to exogenous mechanical loading in males. While previous work demonstrates that VSCCs are essential for anabolic responses to mechanical loading, the mechanism by which these channels sense and respond to force remained unclear. Our data demonstrate that the α2δ1 auxiliary VSCC subunit functions to maintain baseline bone mass and strength through regulation of osteoclast activity, and also provides skeletal mechanotransduction in male mice. These data reveal a molecular player in our understanding of the mechanisms by which VSCCs influence skeletal adaptation.","PeriodicalId":14611,"journal":{"name":"JBMR Plus","volume":"81 4","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139440525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Connor Devine, Kenna Brown, Kat O Patton, Chelsea M Heveran, Stephen A Martin
Advancing age is the strongest risk factor for osteoporosis and skeletal fragility. Rapamycin is an FDA approved immunosuppressant that inhibits the mechanistic target of rapamycin (mTOR) complex, extends lifespan, and protects against aging-related diseases in multiple species; however, the impact of rapamycin on skeletal tissue is incompletely understood. We evaluated the effects of a short-term, low-dosage, interval rapamycin treatment on bone microarchitecture and strength in young-adult (3-months-old) and aged female (20-months-old) C57BL/6 mice. Rapamycin (2 mg/kg body mass) was administered via intraperitoneal injection 1x/5 days for a duration of 8 weeks; this treatment regimen has been shown to induce geroprotective effects while minimizing the side-effects associated with higher rapamycin dosages and/or more frequent or prolonged delivery schedules. Aged femurs exhibited lower cancellous bone mineral density, volume, trabecular connectivity density and number, higher trabecular thickness and spacing, and lower cortical thickness compared to young-adult mice. Rapamycin had no impact on assessed microCT parameters. Flexural testing of the femur revealed yield strength and ultimate strength were lower in aged mice compared to young-adult mice. There were no effects of rapamycin on these or other measures of bone biomechanics. Age, but not rapamycin, altered local and global measures of bone turnover. These data demonstrate a short-term, low-dosage, interval, rapamycin treatment does not negatively or positively impact the skeleton of young-adult and aged mice.
{"title":"Rapamycin does not alter bone microarchitecture or material properties quality in young-adult and aged female C57BL/6 mice","authors":"Connor Devine, Kenna Brown, Kat O Patton, Chelsea M Heveran, Stephen A Martin","doi":"10.1093/jbmrpl/ziae001","DOIUrl":"https://doi.org/10.1093/jbmrpl/ziae001","url":null,"abstract":"\u0000 Advancing age is the strongest risk factor for osteoporosis and skeletal fragility. Rapamycin is an FDA approved immunosuppressant that inhibits the mechanistic target of rapamycin (mTOR) complex, extends lifespan, and protects against aging-related diseases in multiple species; however, the impact of rapamycin on skeletal tissue is incompletely understood. We evaluated the effects of a short-term, low-dosage, interval rapamycin treatment on bone microarchitecture and strength in young-adult (3-months-old) and aged female (20-months-old) C57BL/6 mice. Rapamycin (2 mg/kg body mass) was administered via intraperitoneal injection 1x/5 days for a duration of 8 weeks; this treatment regimen has been shown to induce geroprotective effects while minimizing the side-effects associated with higher rapamycin dosages and/or more frequent or prolonged delivery schedules. Aged femurs exhibited lower cancellous bone mineral density, volume, trabecular connectivity density and number, higher trabecular thickness and spacing, and lower cortical thickness compared to young-adult mice. Rapamycin had no impact on assessed microCT parameters. Flexural testing of the femur revealed yield strength and ultimate strength were lower in aged mice compared to young-adult mice. There were no effects of rapamycin on these or other measures of bone biomechanics. Age, but not rapamycin, altered local and global measures of bone turnover. These data demonstrate a short-term, low-dosage, interval, rapamycin treatment does not negatively or positively impact the skeleton of young-adult and aged mice.","PeriodicalId":14611,"journal":{"name":"JBMR Plus","volume":"2 9","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139440288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aliya A Khan, Lisa G Abbott, Intekhab Ahmed, O. Ayodele, Claudia Gagnon, Richard D Finkelman, Emese Mezosi, Lars Rejnmark, Istvan Takacs, Shaoming Yin, Steven W Ing
Hypoparathyroidism is a rare disease, often inadequately controlled by conventional treatment. PARALLAX was a mandatory post-marketing trial assessing pharmacokinetics and pharmacodynamics of different dosing regimens of recombinant human parathyroid hormone 1–84 (rhPTH[1–84]) for treating hypoparathyroidism. The present study (NCT03364738) was a Phase 4, 1-year open-label extension of PARALLAX. Patients received only two doses of rhPTH(1–84) in PARALLAX and were thus considered treatment-naive at the start of the current study. rhPTH(1–84) was initiated at 50 μg once daily, with doses adjusted based on albumin-corrected serum calcium levels. Albumin-corrected serum calcium (primary outcome measure), health-related quality of life (HRQoL), adverse events, and healthcare resource utilization (HCRU) were assessed. The mean age of the 22 patients included was 50.0 years; 81.8% were women, and 90.9% were White. By end of treatment (EOT), 95.5% of patients had albumin-corrected serum calcium values in the protocol-defined primary endpoint range of 1.88 mmol/L to the upper limit of normal. Serum phosphorus was within the healthy range, and albumin-corrected serum calcium-phosphorus product was below the upper healthy limit throughout, while mean 24-hour urine calcium excretion decreased from baseline to EOT. Mean supplemental doses of calcium and active vitamin D were reduced from baseline to EOT (2402–855 mg/day and 0.8–0.2 μg/day, respectively). Mean serum bone turnover markers, bone-specific alkaline phosphatase, osteocalcin, procollagen type I N-terminal propeptide, and type I collagen C-telopeptide increased 2–5 fold from baseline to EOT. HCRU, disease-related symptoms and impact on HRQoL improved numerically between baseline and EOT. Nine patients (40.9%) experienced treatment-related adverse events; no deaths were reported. Treatment with rhPTH(1–84) once daily for 1 year improved HRQoL, maintained eucalcemia in 95% of patients, normalized serum phosphorus, and decreased urine calcium excretion. The effects observed on urine calcium and the safety profile are consistent with previous findings.
{"title":"Open-label extension of a randomized trial investigating safety and efficacy of rhPTH(1–84) in hypoparathyroidism","authors":"Aliya A Khan, Lisa G Abbott, Intekhab Ahmed, O. Ayodele, Claudia Gagnon, Richard D Finkelman, Emese Mezosi, Lars Rejnmark, Istvan Takacs, Shaoming Yin, Steven W Ing","doi":"10.1093/jbmrpl/ziad010","DOIUrl":"https://doi.org/10.1093/jbmrpl/ziad010","url":null,"abstract":"\u0000 Hypoparathyroidism is a rare disease, often inadequately controlled by conventional treatment. PARALLAX was a mandatory post-marketing trial assessing pharmacokinetics and pharmacodynamics of different dosing regimens of recombinant human parathyroid hormone 1–84 (rhPTH[1–84]) for treating hypoparathyroidism. The present study (NCT03364738) was a Phase 4, 1-year open-label extension of PARALLAX. Patients received only two doses of rhPTH(1–84) in PARALLAX and were thus considered treatment-naive at the start of the current study. rhPTH(1–84) was initiated at 50 μg once daily, with doses adjusted based on albumin-corrected serum calcium levels. Albumin-corrected serum calcium (primary outcome measure), health-related quality of life (HRQoL), adverse events, and healthcare resource utilization (HCRU) were assessed. The mean age of the 22 patients included was 50.0 years; 81.8% were women, and 90.9% were White. By end of treatment (EOT), 95.5% of patients had albumin-corrected serum calcium values in the protocol-defined primary endpoint range of 1.88 mmol/L to the upper limit of normal. Serum phosphorus was within the healthy range, and albumin-corrected serum calcium-phosphorus product was below the upper healthy limit throughout, while mean 24-hour urine calcium excretion decreased from baseline to EOT. Mean supplemental doses of calcium and active vitamin D were reduced from baseline to EOT (2402–855 mg/day and 0.8–0.2 μg/day, respectively). Mean serum bone turnover markers, bone-specific alkaline phosphatase, osteocalcin, procollagen type I N-terminal propeptide, and type I collagen C-telopeptide increased 2–5 fold from baseline to EOT. HCRU, disease-related symptoms and impact on HRQoL improved numerically between baseline and EOT. Nine patients (40.9%) experienced treatment-related adverse events; no deaths were reported. Treatment with rhPTH(1–84) once daily for 1 year improved HRQoL, maintained eucalcemia in 95% of patients, normalized serum phosphorus, and decreased urine calcium excretion. The effects observed on urine calcium and the safety profile are consistent with previous findings.","PeriodicalId":14611,"journal":{"name":"JBMR Plus","volume":"2 5","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Julia Eazer, Mina‐Michael Barsoum, Cole Smith, Kazuki Hotta, Brad Behnke, Christina Holmes, Jacob Caldwell, Payal Ghosh, Emily Reid‐Foley, Hyerim Park, Michael Delp, Judy Muller-Delp
The magnitude of bone formation and remodeling is linked to both the magnitude of strain placed on the bone and the perfusion of bone. It was previously reported that an increase in bone perfusion and bone density occurs in the femur of old rats with moderate aerobic exercise training. This study determined the acute and chronic effects of static muscle stretching on bone blood flow and remodeling. Old male Fischer 344 rats were randomized to either a naïve or stretch-trained group. Static stretching of ankle flexor muscles was achieved by placement of a dorsiflexion splint on the left ankle for 30 min/day, 5d/wk for 4wks. The opposite hindlimb served as a contralateral control (nonstretched) limb. Bone blood flow was assessed during and after acute stretching in naïve rats, and at rest and during exercise in stretch-trained rats. Vascular reactivity of the nutrient artery of the proximal tibia was also assessed in stretch-trained rats. MicroCT analysis was used to assess bone volume and micro-architecture of the trabecular bone of both tibias near that growth plate. In naïve rats, static stretching increased blood flow to the proximal tibial metaphasis. Blood flow to the proximal tibial metaphysis during treadmill exercise was higher in the stretched limb after 4 weeks of daily stretching. Daily stretching also increased tibial bone weight and increased total volume in both the proximal and distal tibial metaphyses. In the trabecular bone immediately below the proximal tibial growth plate, total volume and bone volume increased, but bone volume/total volume was unchanged and trabecular connectivity decreased. In contrast, intravascular volume increased in this region of the bone. These data suggest that blood flow to the tibia increases during bouts of static stretching of the hindlimb muscles, and that 4 weeks of daily muscle stretching leads to bone remodeling and an increase in intravascular volume of the tibial bone.
{"title":"Adaptations of bone and bone vasculature to muscular stretch training","authors":"Julia Eazer, Mina‐Michael Barsoum, Cole Smith, Kazuki Hotta, Brad Behnke, Christina Holmes, Jacob Caldwell, Payal Ghosh, Emily Reid‐Foley, Hyerim Park, Michael Delp, Judy Muller-Delp","doi":"10.1093/jbmrpl/ziad019","DOIUrl":"https://doi.org/10.1093/jbmrpl/ziad019","url":null,"abstract":"\u0000 The magnitude of bone formation and remodeling is linked to both the magnitude of strain placed on the bone and the perfusion of bone. It was previously reported that an increase in bone perfusion and bone density occurs in the femur of old rats with moderate aerobic exercise training. This study determined the acute and chronic effects of static muscle stretching on bone blood flow and remodeling. Old male Fischer 344 rats were randomized to either a naïve or stretch-trained group. Static stretching of ankle flexor muscles was achieved by placement of a dorsiflexion splint on the left ankle for 30 min/day, 5d/wk for 4wks. The opposite hindlimb served as a contralateral control (nonstretched) limb. Bone blood flow was assessed during and after acute stretching in naïve rats, and at rest and during exercise in stretch-trained rats. Vascular reactivity of the nutrient artery of the proximal tibia was also assessed in stretch-trained rats. MicroCT analysis was used to assess bone volume and micro-architecture of the trabecular bone of both tibias near that growth plate. In naïve rats, static stretching increased blood flow to the proximal tibial metaphasis. Blood flow to the proximal tibial metaphysis during treadmill exercise was higher in the stretched limb after 4 weeks of daily stretching. Daily stretching also increased tibial bone weight and increased total volume in both the proximal and distal tibial metaphyses. In the trabecular bone immediately below the proximal tibial growth plate, total volume and bone volume increased, but bone volume/total volume was unchanged and trabecular connectivity decreased. In contrast, intravascular volume increased in this region of the bone. These data suggest that blood flow to the tibia increases during bouts of static stretching of the hindlimb muscles, and that 4 weeks of daily muscle stretching leads to bone remodeling and an increase in intravascular volume of the tibial bone.","PeriodicalId":14611,"journal":{"name":"JBMR Plus","volume":"11 5","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139387496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ilka Maus, M. Dreiner, Sebastian Zetzsche, F. Metzen, Bryony C Ross, D. Mählich, M. Koch, Anja Niehoff, Brunhilde Wirth
PLS3 loss-of-function mutations in humans and mice cause X-linked primary osteoporosis. However, it remains largely unknown how PLS3 mutations cause osteoporosis and which function PLS3 plays in bone homeostasis. A recent study showed that the ubiquitous Pls3 KO in mice results in osteoporosis with decreased bone thickness and stiffness. In these mice, mainly osteoclasts were impacted in their function, exhibiting increased resorptive activity and altered podosome formation through a misregulation of the NFκB pathway. Specifically, Pls3 KO caused the decreased nuclear localization of its interaction partner NFκB repressing factor, NKRF, thereby augmenting Nfatc1 transcription. However, it has not been proven if, indeed, the osteoclasts are the major cell type affected and responsible for the osteoporosis development in ubiquitous Pls3 KO mice. Here, we generated osteoclast-specific Pls3 KO female (Pls3fl/fl; LysMCretg/0) and male (Pls3fl;LysMCretg/0) mice and demonstrate specific PLS3 loss in cultured osteoclasts. In addition, we developed a novel polyclonal PLS3 antibody that showed for the first time specific PLS3 loss in immunofluorescence staining of osteoclasts in contrast to previously available antibodies against PLS3 that failed to show PLS3-specificity in mouse cells. Moreover, we demonstrate that the osteoclast-specific Pls3 KO causes a dramatic increase in the resorptive activity of osteoclasts in vitro. Despite this pronounced effect on osteoclast resorption activity, osteoclast-specific Pls3 KO in vivo failed to cause any osteoporotic phenotype in 12-, 24-, and 48-week-old mice as proven by micro-CT and three-point bending test. These results demonstrate that the pathomechanism of PLS3-associated osteoporosis is highly complex and cannot be reproduced in a system singularly focused on one cell type, leading us to conclude that the loss of PLS3 in alternative bone cell types, such as osteoblasts and osteocytes contributes to the osteoporosis phenotype in ubiquitous Pls3 KO mice.
人类和小鼠的 PLS3 功能缺失突变会导致 X 连锁原发性骨质疏松症。然而，人们对 PLS3 突变如何导致骨质疏松症以及 PLS3 在骨稳态中发挥何种功能仍然知之甚少。最近的一项研究表明，小鼠中无处不在的 Pls3 KO 会导致骨质疏松症，骨厚度和硬度下降。在这些小鼠中，主要是破骨细胞的功能受到影响，表现出更强的吸收活性，并通过 NFκB 通路的误调改变了荚膜体的形成。具体来说，Pls3 KO导致其相互作用伙伴NFκB抑制因子NKRF的核定位减少，从而增强了Nfatc1的转录。然而，尚未证实破骨细胞是否是受影响的主要细胞类型，以及是否是导致无处不在的 Pls3 KO 小鼠发生骨质疏松症的原因。在这里，我们产生了破骨细胞特异性 Pls3 KO 雌性（Pls3fl/fl; LysMCretg/0）和雄性（Pls3fl;LysMCretg/0）小鼠，并在培养的破骨细胞中证明了特异性 PLS3 缺失。此外，我们还开发了一种新型多克隆 PLS3 抗体，该抗体首次在破骨细胞的免疫荧光染色中显示出特异性 PLS3 缺失，而之前可用的 PLS3 抗体未能在小鼠细胞中显示出 PLS3 特异性。此外，我们还证明，破骨细胞特异性 Pls3 KO 会导致体外破骨细胞的吸收活性急剧增加。尽管对破骨细胞的吸收活性有明显的影响，但通过显微 CT 和三点弯曲试验证明，体内破骨细胞特异性 Pls3 KO 在 12 周龄、24 周龄和 48 周龄的小鼠中均未导致任何骨质疏松表型。这些结果表明，与 PLS3 相关的骨质疏松症的病理机制非常复杂，无法在一个只关注一种细胞类型的系统中再现，因此我们得出结论，在其他骨细胞类型（如成骨细胞和骨细胞）中 PLS3 的缺失导致了无处不在的 Pls3 KO 小鼠的骨质疏松症表型。
{"title":"Osteoclast-specific Plastin 3 knockout in mice fail to develop osteoporosis despite dramatic increased osteoclast resorption activity","authors":"Ilka Maus, M. Dreiner, Sebastian Zetzsche, F. Metzen, Bryony C Ross, D. Mählich, M. Koch, Anja Niehoff, Brunhilde Wirth","doi":"10.1093/jbmrpl/ziad009","DOIUrl":"https://doi.org/10.1093/jbmrpl/ziad009","url":null,"abstract":"\u0000 PLS3 loss-of-function mutations in humans and mice cause X-linked primary osteoporosis. However, it remains largely unknown how PLS3 mutations cause osteoporosis and which function PLS3 plays in bone homeostasis. A recent study showed that the ubiquitous Pls3 KO in mice results in osteoporosis with decreased bone thickness and stiffness. In these mice, mainly osteoclasts were impacted in their function, exhibiting increased resorptive activity and altered podosome formation through a misregulation of the NFκB pathway. Specifically, Pls3 KO caused the decreased nuclear localization of its interaction partner NFκB repressing factor, NKRF, thereby augmenting Nfatc1 transcription. However, it has not been proven if, indeed, the osteoclasts are the major cell type affected and responsible for the osteoporosis development in ubiquitous Pls3 KO mice.\u0000 Here, we generated osteoclast-specific Pls3 KO female (Pls3fl/fl; LysMCretg/0) and male (Pls3fl;LysMCretg/0) mice and demonstrate specific PLS3 loss in cultured osteoclasts. In addition, we developed a novel polyclonal PLS3 antibody that showed for the first time specific PLS3 loss in immunofluorescence staining of osteoclasts in contrast to previously available antibodies against PLS3 that failed to show PLS3-specificity in mouse cells. Moreover, we demonstrate that the osteoclast-specific Pls3 KO causes a dramatic increase in the resorptive activity of osteoclasts in vitro. Despite this pronounced effect on osteoclast resorption activity, osteoclast-specific Pls3 KO in vivo failed to cause any osteoporotic phenotype in 12-, 24-, and 48-week-old mice as proven by micro-CT and three-point bending test. These results demonstrate that the pathomechanism of PLS3-associated osteoporosis is highly complex and cannot be reproduced in a system singularly focused on one cell type, leading us to conclude that the loss of PLS3 in alternative bone cell types, such as osteoblasts and osteocytes contributes to the osteoporosis phenotype in ubiquitous Pls3 KO mice.","PeriodicalId":14611,"journal":{"name":"JBMR Plus","volume":"39 11","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139450710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christopher de la Bastide, Lissa Soares, L. Lui, James Harrington, Peggy Cawthon, Eric Orwoll, Deborah Kado, Jaymie Meliker
Cadmium (Cd) is a heavy metal and natural element found in soil and crops with increasing concentrations linked to phosphate fertilizers and sewage sludge applied to crop lands. A large fraction of older U.S men and woman have documented Cd exposure. Cd exposure has proven health concerns such as risk of lung cancer from inhalation and impaired renal function, however, growing evidence suggests it also influences bone and muscle health. Given that low levels of Cd could affect bone and muscle, we have designed prospective studies using the two largest and most detailed U.S. studies of bone health in older men and women: The Osteoporotic Fractures in Men (MrOS) Study and the Study of Osteoporotic Fractures (SOF). We are investigating the association of urinary cadmium (U-Cd), as a surrogate for long term cadmium exposure, with bone and muscle health. Building off suggestive evidence from mechanistic and cross-sectional studies, this will be the first well-powered prospective study of incident fracture outcomes, bone loss, and muscle loss in relation to U-Cd, an established biomarker of long-term Cd exposure. The following is a proposed protocol for the intended study; if successful the proposed studies could be influential in directing future U.S policy to decrease Cd exposure in the U.S population similar to recent policies adopted by the European Union to limit Cd in fertilizers.
{"title":"A protocol for the prospective study of urinary cadmium with risk of fracture, bone loss, and muscle loss","authors":"Christopher de la Bastide, Lissa Soares, L. Lui, James Harrington, Peggy Cawthon, Eric Orwoll, Deborah Kado, Jaymie Meliker","doi":"10.1093/jbmrpl/ziad006","DOIUrl":"https://doi.org/10.1093/jbmrpl/ziad006","url":null,"abstract":"\u0000 Cadmium (Cd) is a heavy metal and natural element found in soil and crops with increasing concentrations linked to phosphate fertilizers and sewage sludge applied to crop lands. A large fraction of older U.S men and woman have documented Cd exposure. Cd exposure has proven health concerns such as risk of lung cancer from inhalation and impaired renal function, however, growing evidence suggests it also influences bone and muscle health. Given that low levels of Cd could affect bone and muscle, we have designed prospective studies using the two largest and most detailed U.S. studies of bone health in older men and women: The Osteoporotic Fractures in Men (MrOS) Study and the Study of Osteoporotic Fractures (SOF). We are investigating the association of urinary cadmium (U-Cd), as a surrogate for long term cadmium exposure, with bone and muscle health. Building off suggestive evidence from mechanistic and cross-sectional studies, this will be the first well-powered prospective study of incident fracture outcomes, bone loss, and muscle loss in relation to U-Cd, an established biomarker of long-term Cd exposure. The following is a proposed protocol for the intended study; if successful the proposed studies could be influential in directing future U.S policy to decrease Cd exposure in the U.S population similar to recent policies adopted by the European Union to limit Cd in fertilizers.","PeriodicalId":14611,"journal":{"name":"JBMR Plus","volume":"44 24","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139387003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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