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Youssef EM, Wu GY. Subnormal Serum Liver Enzyme Levels: A Review of Pathophysiology and Clinical Significance. J Clin Transl Hepatol 2024; 12:428-435. [PMID: 38638374 PMCID: PMC11022067 DOI: 10.14218/jcth.2023.00446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/09/2024] [Accepted: 02/18/2024] [Indexed: 04/20/2024] Open
Abstract
Subnormal levels of liver enzymes, below the lower limit of normal on local laboratory reports, can be useful diagnostically. For instance, subnormal levels of aminotransferases can be observed in vitamin B6 deficiency and chronic kidney disease. Subnormal alkaline phosphatase levels may indicate the presence of hypophosphatasia, Wilson's disease, deficiencies of divalent ions, or malnutrition. Subnormal levels of gamma glutamyl transferase may be seen in cases of acute intrahepatic cholestasis, the use of certain medications, and in bone disease. Finally, subnormal levels of 5'-nucleotidase have been reported in lead poisoning and nonspherocytic hemolytic anemia. The aim of this review is to bring attention to the fact that subnormal levels of these enzymes should not be ignored as they may indicate pathological conditions and provide a means of early diagnosis.
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Affiliation(s)
| | - George Y. Wu
- Department of Medicine, Division of Gastroenterology-Hepatology, University of Connecticut Health Center, Farmington, CT, USA
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2
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Li P, Pang Y, He S, Duan J, Gong H, Yan Y, Shi J. Gamma-glutamyl transferase and calculus of kidney incidence: a Mendelian randomization study. Sci Rep 2023; 13:21821. [PMID: 38071316 PMCID: PMC10710451 DOI: 10.1038/s41598-023-48610-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
Elevated Gamma-glutamyl transferase (GGT) levels are often suggestive of cholelithiasis, and previous studies have indicated that GGT is highly expressed in the urinary system. Therefore, we hypothesized that there may be an association between GGT levels and calculus of kidney (CK) incidence. To investigate this potential causal relationship, we employed Mendelian randomization (MR) analysis. Additionally, we analyzed the levels of other liver enzymes, including alanine transaminase (ALT) and alkaline phosphatase (ALP). The relationship between GGT levels and CK incidence was analyzed using two-sample Mendelian randomization. Summary Genome-Wide Association Studies data were utilized for this analysis. 33 single nucleotide polymorphisms known to be associated with GGT levels were employed as instrumental variables. We employed several MR methods including IVW (inverse variance weighting), MR-Egger, weighted median, weighted mode, and MR-PRESSO (Mendelian Randomization Pleiotropy RESidual Sum and Outlier). Furthermore, we conducted tests for horizontal multivariate validity, heterogeneity, and performed leave-one-out analysis to ensure the stability of the results. Overall, several MR methods yielded statistically significant results with a p-value < 0.05. The results from the IVW analysis yielded an odds ratio (OR) of 1.0062 with a 95% confidence interval (CI) of 1.0016-1.0109 (p = 0.0077). Additional MR methods provided supplementary results: MR-Egger (OR 1.0167, 95% CI 1.0070-1.0266, p = 0.0040); weighted median (OR 1.0058, 95% CI 1.0002-1.0115, p = 0.0423); and weighted mode (OR 1.0083, 95% CI 1.0020-1.0146, p- = 0.0188). Sensitivity analyses did not reveal heterogeneity or outliers. Although potential horizontal pleiotropy emerged, we speculate that this could be attributed to inadequate test efficacy. However, subsequent use of MR-PRESSO did not provide evidence of pleiotropy. Our analysis suggests a positive association between elevated GGT levels and CK incidence, indicating an increased risk of CK development. However, no causal relationship was observed between levels of ALP or ALT and CK incidence.
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Affiliation(s)
- Peizhe Li
- Department of Urology, Dongzhimen Hospital, Beijing University of Chinese Medicine, Hai Yun Cang On the 5th Zip, Dongcheng District, Beijing, 10000, China
| | - Yuewen Pang
- Department of Urology, Dongzhimen Hospital, Beijing University of Chinese Medicine, Hai Yun Cang On the 5th Zip, Dongcheng District, Beijing, 10000, China
| | - Shuang He
- Department of Urology, Dongzhimen Hospital, Beijing University of Chinese Medicine, Hai Yun Cang On the 5th Zip, Dongcheng District, Beijing, 10000, China
| | - Junyao Duan
- Department of Urology, Dongzhimen Hospital, Beijing University of Chinese Medicine, Hai Yun Cang On the 5th Zip, Dongcheng District, Beijing, 10000, China
| | - Huijie Gong
- Department of Urology, Dongzhimen Hospital, Beijing University of Chinese Medicine, Hai Yun Cang On the 5th Zip, Dongcheng District, Beijing, 10000, China
| | - Yongji Yan
- Department of Urology, Dongzhimen Hospital, Beijing University of Chinese Medicine, Hai Yun Cang On the 5th Zip, Dongcheng District, Beijing, 10000, China.
| | - Jing Shi
- Department of Urology, Dongzhimen Hospital, Beijing University of Chinese Medicine, Hai Yun Cang On the 5th Zip, Dongcheng District, Beijing, 10000, China.
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3
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Kim D, Kim JH, Lee H, Hong I, Chang Y, Song TJ. Association of gamma-glutamyl transferase variability with risk of osteoporotic fractures: A nationwide cohort study. PLoS One 2023; 18:e0277452. [PMID: 37267386 DOI: 10.1371/journal.pone.0277452] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/19/2023] [Indexed: 06/04/2023] Open
Abstract
OBJECTIVES Gamma-glutamyl transferase (GGT) is related to inflammation, osteoporosis, and vascular diseases. Recently, changes in metabolic parameters have been proposed as osteoporosis biomarkers. We aimed to assess longitudinally the association of GGT variability with osteoporotic fractures. METHODS From the National Health Insurance Service-Health Screening Cohort database, participants who underwent three or more health examinations between 2003 and 2008 were included (n = 1,072,432). Variability indexes were as follows: (1) coefficient of variation (CV), (2) standard deviation (SD), and (3) variability independent of the mean (VIM). The primary outcome was occurrence of osteoporotic fracture, defined as identification of one of the following international classification of diseases-10 codes: vertebral fractures (S22.0, S22.1, S32.0, S32.7, T08, M48.4, M48.5, M49.5), hip fractures (S72.0, S72.1), distal radius fractures (S52.5, S52.6), or humerus fractures (S42.2, S42.3). RESULTS During a median of 12.3 years (interquartile range 12.1-12.6), osteoporotic fractures occurred in 49,677 (4.6%) participants. In multivariable analysis, GGT variability based on CV positively correlated with the occurrence of osteoporotic fracture (adjusted hazard ratio [HR] of the highest quartile compared with the lowest quartile 1.15, 95% confidence interval [CI] 1.12-1.18, P < 0.001). These results were consistent even when GGT variability was defined by SD (adjusted HR 1.22, 95% CI 1.19-1.25, P < 0.001) and VIM (adjusted HR 1.12, 95% CI 1.09-1.15, P < 0.001). CONCLUSIONS Increased GGT variability is associated with an increased risk of osteoporotic fractures in the Korean population. Maintaining constant and stable GGT level may help reduce the risk of osteoporotic fractures.
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Affiliation(s)
- Dongyeop Kim
- Department of Neurology, Seoul Hospital, Ewha Womans University College of Medicine, Seoul, Republic of Korea
| | - Jee Hyun Kim
- Department of Neurology, Seoul Hospital, Ewha Womans University College of Medicine, Seoul, Republic of Korea
| | - Heajung Lee
- Department of Neurology, Seoul Hospital, Ewha Womans University College of Medicine, Seoul, Republic of Korea
| | - Iksun Hong
- Department of Neurology, Seoul Hospital, Ewha Womans University College of Medicine, Seoul, Republic of Korea
| | - Yoonkyung Chang
- Department of Neurology, Mokdong Hospital, Ewha Womans University College of Medicine, Seoul, Republic of Korea
| | - Tae-Jin Song
- Department of Neurology, Seoul Hospital, Ewha Womans University College of Medicine, Seoul, Republic of Korea
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Russo S, Scotto di Carlo F, Maurizi A, Fortunato G, Teti A, Licastro D, Settembre C, Mello T, Gianfrancesco F. A mutation in the ZNF687 gene that is responsible for the severe form of Paget's disease of bone causes severely altered bone remodeling and promotes hepatocellular carcinoma onset in a knock-in mouse model. Bone Res 2023; 11:16. [PMID: 36918542 PMCID: PMC10014847 DOI: 10.1038/s41413-023-00250-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 01/12/2023] [Accepted: 02/05/2023] [Indexed: 03/16/2023] Open
Abstract
Paget's disease (PDB) is a late-onset bone remodeling disorder with a broad spectrum of symptoms and complications. One of the most aggressive forms is caused by the P937R mutation in the ZNF687 gene. Although the genetic involvement of ZNF687 in PDB has been extensively studied, the molecular mechanisms underlying this association remain unclear. Here, we describe the first Zfp687 knock-in mouse model and demonstrate that the mutation recapitulates the PDB phenotype, resulting in severely altered bone remodeling. Through microcomputed tomography analysis, we observed that 8-month-old mutant mice showed a mainly osteolytic phase, with a significant decrease in the trabecular bone volume affecting the femurs and the vertebrae. Conversely, osteoblast activity was deregulated, producing disorganized bone. Notably, this phenotype became pervasive in 16-month-old mice, where osteoblast function overtook bone resorption, as highlighted by the presence of woven bone in histological analyses, consistent with the PDB phenotype. Furthermore, we detected osteophytes and intervertebral disc degeneration, outlining for the first time the link between osteoarthritis and PDB in a PDB mouse model. RNA sequencing of wild-type and Zfp687 knockout RAW264.7 cells identified a set of genes involved in osteoclastogenesis potentially regulated by Zfp687, e.g., Tspan7, Cpe, Vegfc, and Ggt1, confirming its role in this process. Strikingly, in this mouse model, the mutation was also associated with a high penetrance of hepatocellular carcinomas. Thus, this study established an essential role of Zfp687 in the regulation of bone remodeling, offering the potential to therapeutically treat PDB, and underlines the oncogenic potential of ZNF687.
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Affiliation(s)
- Sharon Russo
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", National Research Council of Italy, Naples, Italy.,Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), University of Campania Luigi Vanvitelli, Caserta, Italy
| | - Federica Scotto di Carlo
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", National Research Council of Italy, Naples, Italy
| | - Antonio Maurizi
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Giorgio Fortunato
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", National Research Council of Italy, Naples, Italy.,Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), University of Campania Luigi Vanvitelli, Caserta, Italy
| | - Anna Teti
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | | | - Carmine Settembre
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Tommaso Mello
- Gastroenterology Unit, Department of Experimental and Clinical Biochemical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Fernando Gianfrancesco
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", National Research Council of Italy, Naples, Italy. .,IRCCS INM Neuromed, Pozzilli, IS, Italy.
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5
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Kim MJ, Kim MS, Lee HB, Roh JH, Jeon JH. Relationship between the High Fatty Liver Index and Risk of Fracture. Gut Liver 2023; 17:119-129. [PMID: 35892266 PMCID: PMC9840917 DOI: 10.5009/gnl210571] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 04/15/2022] [Accepted: 05/03/2022] [Indexed: 02/01/2023] Open
Abstract
Background/Aims The prevalence of nonalcoholic fatty liver disease (NAFLD) has increased rapidly as a consequence of more sedentary lifestyles and a Westernized diet. Fracture is a major clinical problem in older people, but few large-scale cohort studies have evaluated the relationship between NAFLD and fracture. Therefore, we aimed to determine whether the fatty liver index (FLI), which represents the severity of NAFLD, can predict fracture risk. Methods We analyzed the relationship between the FLI and incident fracture using multivariate Cox proportional hazards models and data for 180,519 individuals who underwent National Health check-ups in the Republic of Korea between 2009 and 2014. Results A total of 2,720 participants (1.5%) were newly diagnosed with fracture during the study period (median 4.6 years). The participants were grouped according to FLI quartiles (Q1, 0 to <5.653; Q2, 5.653 to <15.245; Q3, 15.245 to <37.199; and Q4 ≥37.199). The cumulative fracture incidence was significantly higher in the highest FLI group than in the lowest FLI group (Q4, 986 [2.2%] and Q1, 323 [0.7%]; p<0.001). The adjusted hazard ratio indicated that the highest FLI group was independently associated with a higher incidence of fracture (hazard ratio for Q4 vs Q1, 2.956; 95% confidence interval, 2.606 to 3.351; p<0.001). FLI was significantly associated with a higher incidence of fracture, independent of the baseline characteristics of the participants. Conclusions Our data imply that the higher the FLI of a Korean patient is, the higher their risk of osteoporotic fracture, independent of key confounding factors. (Gut Liver, Published online July 27, 2022).
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Affiliation(s)
- Min-Ji Kim
- Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Min-Su Kim
- Department of Internal Medicine, Chungnam National University Sejong Hospital, Chungnam National University College of Medicine, Sejong, Korea
| | - Han-Byul Lee
- Department of Statistics, Kyungpook National University, Daegu, Korea
| | - Jae-Hyung Roh
- Department of Internal Medicine, Chungnam National University Sejong Hospital, Chungnam National University College of Medicine, Sejong, Korea
| | - Jae-Han Jeon
- Department of Internal Medicine, Kyungpook National University Chilgok Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
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6
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Corti A, Belcastro E, Dominici S, Maellaro E, Pompella A. The dark side of gamma-glutamyltransferase (GGT): Pathogenic effects of an 'antioxidant' enzyme. Free Radic Biol Med 2020; 160:807-819. [PMID: 32916278 DOI: 10.1016/j.freeradbiomed.2020.09.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/26/2020] [Accepted: 09/01/2020] [Indexed: 12/16/2022]
Abstract
Having long been regarded as just a member in the cellular antioxidant systems, as well as a clinical biomarker of hepatobiliary diseases and alcohol abuse, gamma-glutamyltransferase (GGT) enzyme activity has been highlighted by more recent research as a critical factor in modulation of redox equilibria within the cell and in its surroundings. Moreover, due to the prooxidant reactions which can originate during its metabolic function in selected conditions, experimental and clinical studies are increasingly involving GGT in the pathogenesis of several important disease conditions, such as atherosclerosis, cardiovascular diseases, cancer, lung inflammation, neuroinflammation and bone disorders. The present article is an overview of the laboratory findings that have prompted an evolution in interpretation of the significance of GGT in human pathophysiology.
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Affiliation(s)
- Alessandro Corti
- Dept. of Translational Research NTMS, University of Pisa Medical School, Italy
| | - Eugenia Belcastro
- Dept. of Translational Research NTMS, University of Pisa Medical School, Italy
| | - Silvia Dominici
- Dept. of Translational Research NTMS, University of Pisa Medical School, Italy
| | - Emilia Maellaro
- Dept. of Molecular and Developmental Medicine, University of Siena, Italy
| | - Alfonso Pompella
- Dept. of Translational Research NTMS, University of Pisa Medical School, Italy.
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7
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Brown SJ, Harrington GMB, Hulme CH, Morris R, Bennett A, Tsang WH, Osman A, Chowdhury J, Kumar N, Wright KT. A Preliminary Cohort Study Assessing Routine Blood Analyte Levels and Neurological Outcome after Spinal Cord Injury. J Neurotrauma 2019; 37:466-480. [PMID: 31310157 PMCID: PMC6978787 DOI: 10.1089/neu.2019.6495] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
There is increasing interest in the identification of biomarkers that could predict neurological outcome following a spinal cord injury (SCI). Although initial American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade is a good indicator of neurological outcome, for the patient and clinicians, an element of uncertainty remains. This preliminary study aimed to assess the additive potential of routine blood analytes following principal component analysis (PCA) to develop prognostic models for neurological outcome following SCI. Routine blood and clinical data were collected from SCI patients (n = 82) and PCA used to reduce the number of blood analytes into related factors. Outcome neurology was obtained from AIS scores at 3 and 12 months post-injury, with motor (AIS and total including all myotomes) and sensory (AIS, touch and pain) abilities being assessed individually. Multiple regression models were created for all outcome measures. Blood analytes relating to “liver function” and “acute inflammation and liver function” factors were found to significantly increase prediction of neurological outcome at both 3 months (touch, pain, and AIS sensory) and at 1 year (pain, R2 increased by 0.025 and total motor, R2 increased by 0.016). For some models “liver function” and “acute inflammation and liver function” factors were both significantly predictive, with the greatest combined R2 improvement of 0.043 occurring for 3 month pain prediction. These preliminary findings support ongoing research into the use of routine blood analytes in the prediction of neurological outcome in SCI patients.
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Affiliation(s)
- Sharon J Brown
- Institute of Science and Technology in Medicine (ISTM), Keele University, Keele, United Kingdom.,Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, United Kingdom
| | - Gabriel M B Harrington
- Institute of Science and Technology in Medicine (ISTM), Keele University, Keele, United Kingdom.,Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, United Kingdom
| | - Charlotte H Hulme
- Institute of Science and Technology in Medicine (ISTM), Keele University, Keele, United Kingdom.,Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, United Kingdom
| | - Rachel Morris
- Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, United Kingdom
| | - Anna Bennett
- Life Sciences, University of Chester, Chester, Cheshire, United Kingdom
| | - Wai-Hung Tsang
- Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, United Kingdom
| | - Aheed Osman
- Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, United Kingdom
| | - Joy Chowdhury
- Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, United Kingdom
| | - Naveen Kumar
- Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, United Kingdom
| | - Karina T Wright
- Institute of Science and Technology in Medicine (ISTM), Keele University, Keele, United Kingdom.,Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, United Kingdom
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Do HJ, Shin JS, Lee J, Lee YJ, Kim MR, Nam D, Kim EJ, Park Y, Suhr K, Ha IH. Association between liver enzymes and bone mineral density in Koreans: a cross-sectional study. BMC Musculoskelet Disord 2018; 19:410. [PMID: 30474546 PMCID: PMC6260874 DOI: 10.1186/s12891-018-2322-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 10/25/2018] [Indexed: 01/03/2023] Open
Abstract
Background Osteoporosis is a major health concern for both men and women, and associated fractures incur substantial economic burden. While there are a multitude of studies on bone mineral density (BMD) and liver diseases, not many studies have assessed the association between liver enzyme levels and BMD in homogeneous populations. Methods The current study investigated the association between serum liver enzyme levels and BMD at various sites in Koreans. Out of 21,517 surveyees of the 5th Korean National Health and Nutrition Examination Survey (2010–2012), 7160 participants’ data on BMD, serum liver enzymes, and full covariate data were included for cross-sectional analysis. BMD at the femoral neck, lumbar spine, entire femur, and whole body was assessed using dual energy X-ray absorptiometry (DEXA), and liver enzymes included aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma(γ)-glutamyl transferase (GGT) levels. Differences in participant characteristics by BMD and liver enzyme levels were analyzed, and complex sample design regression analysis adjusted for multiple covariates was performed to assess the relationship between liver enzymes and BMD. Results Negative associations were seen with GGT and BMD at all sites (P ≤ 0.02), ALT with lumbar spine (P = 0.0013), and AST with lumbar BMD (P = 0.0009). In particular, GGT presented strong negative associations with BMD in postmenopausal women and elder men. Conclusions This study demonstrates a negative relationship between liver enzyme levels and BMD, and suggests that a significant association exists between osteoporosis/decreased BMD and liver disorders. Electronic supplementary material The online version of this article (10.1186/s12891-018-2322-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ho Jeong Do
- Jaseng Hospital of Korean Medicine, 536 Gangnam-daero, Gangnam-gu, Seoul, Republic of Korea
| | - Joon-Shik Shin
- Jaseng Hospital of Korean Medicine, 536 Gangnam-daero, Gangnam-gu, Seoul, Republic of Korea
| | - Jinho Lee
- Jaseng Hospital of Korean Medicine, 536 Gangnam-daero, Gangnam-gu, Seoul, Republic of Korea
| | - Yoon Jae Lee
- Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, 538 Gangnam-daero, Gangnam-gu, Seoul, Republic of Korea
| | - Me-Riong Kim
- Jaseng Hospital of Korean Medicine, 536 Gangnam-daero, Gangnam-gu, Seoul, Republic of Korea
| | - Dongwoo Nam
- Department of Acupuncture & Moxibustion, College of Korean Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul, Republic of Korea
| | - Eun-Jung Kim
- Department of Acupuncture & Moxibustion, College of Korean Medicine, Dongguk University, 123 Dongdae-ro, Gyeongju, Gyeongsangbuk-do, Republic of Korea
| | - Yeoncheol Park
- Department of Acupuncture & Moxibustion, Kyung Hee University Hospital at Gangdong, 892 Dongnam-ro, Gangdong-gu, Seoul, Republic of Korea
| | - Kristin Suhr
- Prevention Sciences, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - In-Hyuk Ha
- Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, 538 Gangnam-daero, Gangnam-gu, Seoul, Republic of Korea.
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Seki A, Ikeda F, Miyatake H, Takaguchi K, Hayashi S, Osawa T, Fujioka SI, Tanaka R, Ando M, Seki H, Iwasaki Y, Yamamoto K, Okada H. Risk of secondary osteoporosis due to lobular cholestasis in non-cirrhotic primary biliary cholangitis. J Gastroenterol Hepatol 2017; 32:1611-1616. [PMID: 28114749 DOI: 10.1111/jgh.13746] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 12/28/2016] [Accepted: 01/18/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIM It remains unclear whether primary biliary cholangitis (PBC) represents a risk factor for secondary osteoporosis. METHODS A case-control study was conducted to examine bone mineral density and bone turnover markers in middle-aged postmenopausal PBC patients without liver cirrhosis. We compared the incidence of low bone mineral density between propensity-score matched subgroups of PBC patients and healthy controls and investigated the mechanisms underlying unbalanced bone turnover in terms of the associations between bone turnover markers and PBC-specific histological findings. RESULT Our analysis included 128 consecutive PBC patients, all postmenopausal women aged in their 50s or 60s, without liver cirrhosis or fragility fracture at the time of PBC diagnosis. The prevalence of osteoporosis was significantly higher in the PBC group than in the control group (26% vs 10%, P = 0.015, the Fisher exact probability test). In most PBC patients (95%), the level of bone-specific alkaline phosphatase was above the normal range, indicating increased bone formation. On the other hand, the urine type I collagen-cross-linked N-telopeptide showed variable levels among our PBC patients, indicating unbalanced bone resorption. Advanced fibrosis was associated with low bone turnover. Lobular cholestasis, evaluated as aberrant keratin 7 expression in hepatocytes, showed significant negative correlations with bone formation and resorption, indicating low bone turnover. CONCLUSION Our results show that, compared with healthy controls, even non-cirrhotic PBC patients have significantly higher risk of osteoporosis. Moreover, lobular cholestasis was associated with low bone turnover, suggesting this feature of PBC may itself cause secondary osteoporosis in PBC patients.
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Affiliation(s)
- Anna Seki
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Fusao Ikeda
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Hirokazu Miyatake
- Department of Internal Medicine, Hiroshima City Hospital, Hiroshima, Japan
| | - Koichi Takaguchi
- Department of Internal Medicine, Kagawa Prefectural Central Hospital, Takamatsu, Japan
| | - Shosaku Hayashi
- Department of Internal Medicine, Ritsurin General Hospital, Takamatsu, Japan
| | - Toshiya Osawa
- Department of Internal Medicine, Okayama Saiseikai General Hospital, Okayama, Japan
| | - Shin-Ichi Fujioka
- Department of Internal Medicine, Okayama Saiseikai General Hospital, Okayama, Japan
| | - Ryoji Tanaka
- Department of Internal Medicine, Okayama Saiseikai General Hospital, Okayama, Japan
| | - Masaharu Ando
- Department of Internal Medicine, Mitoyo General Hospital, Kanonji, Japan
| | - Hiroyuki Seki
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Yoshiaki Iwasaki
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Kazuhide Yamamoto
- Department of Internal Medicine, Okayama Saiseikai General Hospital, Okayama, Japan
| | - Hiroyuki Okada
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
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10
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Long Y, Jia D, Wei L, Yang Y, Tian H, Chen T. Liver-Specific Overexpression of Gamma-Glutamyltransferase Ameliorates Insulin Sensitivity of Male C57BL/6 Mice. J Diabetes Res 2017; 2017:2654520. [PMID: 28660214 PMCID: PMC5474247 DOI: 10.1155/2017/2654520] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 04/18/2017] [Accepted: 05/04/2017] [Indexed: 02/05/2023] Open
Abstract
In the current study, we developed a liver-specific GGT-overexpressing mice model by rapid injection pLIVE-GGT vector through tail vein and investigated the effects of GGT elevation on glucose metabolism and insulin sensitivity. The serum GGT activity was significantly increased after 7 days of pLIVE-GGT1 vector delivery and lasted for about 3 weeks. GGT overexpression reduced the levels of GSSG and GSH in the liver and serum and had no effects on total antioxidative capacity in the liver, kidney, and skeletal muscle except for the pancreas. Increased GGT activity had no effect on the glucose tolerance but could facilitate blood glucose lowering after intraperitoneal insulin administration. The results of Western blotting showed that increased GGT activity enhanced insulin-induced AKT phosphorylation at Ser473. Furthermore, GGT inhibitor could attenuate the changes of insulin-induced blood glucose uptake and AKT phosphorylation in the liver. In summary, the present study developed a liver-specific GGT-overexpressing mice model and found that GGT elevation in short term had no effects on glucose metabolism but could increase insulin sensitivity through enhancing the activity of insulin signaling pathway.
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Affiliation(s)
- Yang Long
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China
- Laboratory of Endocrinology, Experimental Medicine Center, The Affiliated Hospital of Southwest Medical University, Luzhou 646000, China
| | - Dan Jia
- Division of General Practice, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Libin Wei
- Department of Stomatology, Hebei Medical University Affiliated North China Petroleum Bureau General Hospital, Renqiu 062552, China
| | - Yumei Yang
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China
- Health Examination Management Center, Sichuan Province People's Hospital, Chengdu 610072, China
| | - Haoming Tian
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China
- *Haoming Tian: and
| | - Tao Chen
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China
- *Tao Chen:
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11
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Kunutsor SK. Gamma-glutamyltransferase-friend or foe within? Liver Int 2016; 36:1723-1734. [PMID: 27512925 DOI: 10.1111/liv.13221] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 08/05/2016] [Indexed: 02/13/2023]
Abstract
Gamma-glutamyltransferase (GGT) is a liver enzyme, which is located on the plasma membranes of most cells and organ tissues, but more commonly in hepatocytes, and is routinely used in clinical practice to help indicate liver injury and as a marker of excessive alcohol consumption. Among the liver enzymes, important advances have especially been made in understanding the physiological functions of GGT. The primary role of GGT is the extracellular catabolism of glutathione, the major thiol antioxidant in mammalian cells, which plays a relevant role in protecting cells against oxidants produced during normal metabolism; GGT, therefore, plays an important role in cellular defence. Beyond its physiological functions, circulating serum GGT has been linked to a remarkable array of chronic conditions and diseases, which include nonalcoholic fatty liver disease, vascular and nonvascular diseases and mortality outcomes. This review summarizes the available epidemiological and genetic evidence for the associations between GGT and these adverse outcomes, the postulated biologic mechanisms underlying these associations, outlines areas of outstanding uncertainty and the implications for clinical practice.
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Moriwaki S, Into T, Suzuki K, Miyauchi M, Takata T, Shibayama K, Niida S. γ-Glutamyltranspeptidase is an endogenous activator of Toll-like receptor 4-mediated osteoclastogenesis. Sci Rep 2016; 6:35930. [PMID: 27775020 PMCID: PMC5075938 DOI: 10.1038/srep35930] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 10/07/2016] [Indexed: 12/14/2022] Open
Abstract
Chronic inflammation-associated bone destruction, which is observed in rheumatoid arthritis (RA) and periodontitis, is mediated by excessive osteoclastogenesis. We showed previously that γ-glutamyltranspeptidase (GGT), an enzyme involved in glutathione metabolism, acts as an endogenous activator of such pathological osteoclastogenesis, independent of its enzymatic activity. GGT accumulation is clinically observed in the joints of RA patients, and, in animals, the administration of recombinant GGT to the gingival sulcus as an in vivo periodontitis model induces an increase in the number of osteoclasts. However, the underlying mechanisms of this process remain unclear. Here, we report that Toll-like receptor 4 (TLR4) recognizes GGT to activate inflammation-associated osteoclastogenesis. Unlike lipopolysaccharide, GGT is sensitive to proteinase K treatment and insensitive to polymyxin B treatment. TLR4 deficiency abrogates GGT-induced osteoclastogenesis and activation of NF-κB and MAPK signaling in precursor cells. Additionally, GGT does not induce osteoclastogenesis in cells lacking the signaling adaptor MyD88. The administration of GGT to the gingival sulcus induces increased osteoclastogenesis in wild-type mice, but does not induce it in TLR4-deficient mice. Our findings elucidate a novel mechanism of inflammation-associated osteoclastogenesis, which involves TLR4 recognition of GGT and subsequent activation of MyD88-dependent signaling.
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Affiliation(s)
- Sawako Moriwaki
- Biobank, Medical Genome Center, National Center for Geriatrics and Gerontology, Obu 474-8511, Japan
| | - Takeshi Into
- Department of Oral Microbiology, Division of Oral Infections and Health Sciences, Asahi University School of Dentistry, Mizuho 501-0296, Japan
| | - Keiko Suzuki
- Department of Pharmacology, School of Dentistry, Showa University, Tokyo 142-8555, Japan
| | - Mutsumi Miyauchi
- Department of Oral and Maxillofacial Pathology, Institute of Biomedical &Health Sciences, Hiroshima University, Hiroshima 734-8522, Japan
| | - Takashi Takata
- Department of Oral and Maxillofacial Pathology, Institute of Biomedical &Health Sciences, Hiroshima University, Hiroshima 734-8522, Japan
| | - Keigo Shibayama
- Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo 208-0011, Japan
| | - Shumpei Niida
- Biobank, Medical Genome Center, National Center for Geriatrics and Gerontology, Obu 474-8511, Japan
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Choi HS, Kim KJ, Rhee Y, Lim SK. Serum γ-Glutamyl Transferase Is Inversely Associated with Bone Mineral Density Independently of Alcohol Consumption. Endocrinol Metab (Seoul) 2016; 31:64-71. [PMID: 26676328 PMCID: PMC4803563 DOI: 10.3803/enm.2016.31.1.64] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 09/07/2015] [Accepted: 10/13/2015] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND γ-Glutamyl transferase (GGT) is a well-known marker of chronic alcohol consumption or hepatobiliary diseases. A number of studies have demonstrated that serum levels of GGT are independently associated with cardiovascular and metabolic disorders. The purpose of this study was to test if serum GGT levels are associated with bone mineral density (BMD) in Korean adults. METHODS A total of 462 subjects (289 men and 173 women), who visited Severance Hospital for medical checkup, were included in this study. BMD was measured using dual energy X-ray absorptiometry. Cross-sectional association between serum GGT and BMD was evaluated. RESULTS As serum GGT levels increased from the lowest tertile (tertile 1) to the highest tertile (tertile 3), BMD decreased after adjusting for confounders such as age, body mass index, amount of alcohol consumed, smoking, regular exercise, postmenopausal state (in women), hypertension, diabetes mellitus, and hypercholesterolemia. A multiple linear regression analysis showed a negative association between log-transformed serum GGT levels and BMD. In a multiple logistic regression analysis, tertile 3 of serum GGT level was associated with an increased risk for low bone mass compared to tertile 1 (odds ratio, 2.271; 95% confidence interval, 1.340 to 3.850; P=0.002). CONCLUSION Serum GGT level was inversely associated with BMD in Korean adults. Further study is necessary to fully elucidate the mechanism of the inverse relationship.
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Affiliation(s)
- Han Seok Choi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, Goyang, Korea
| | - Kwang Joon Kim
- Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- Severance Check-up, Severance Hospital, Yonsei University Health System, Seoul, Korea
- Severance Executive Healthcare Clinic, Severance Hospital, Yonsei University Health System, Seoul, Korea
| | - Yumie Rhee
- Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Sung Kil Lim
- Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
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Kawazoe Y, Miyauchi M, Nagasaki A, Furusho H, Yanagisawa S, Chanbora C, Inubushi T, Hyogo H, Nakamoto T, Suzuki K, Moriwaki S, Tazuma S, Niida S, Takata T. Osteodystrophy in Cholestatic Liver Diseases Is Attenuated by Anti-γ-Glutamyl Transpeptidase Antibody. PLoS One 2015; 10:e0139620. [PMID: 26418133 PMCID: PMC4587927 DOI: 10.1371/journal.pone.0139620] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/14/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Cholestatic liver diseases exhibit higher levels of serum γ-glutamyl transpeptidase (GGT) and incidence of secondary osteoporosis. GGT has been identified as a novel bone-resorbing factor that stimulates osteoclast formation. The aim of this study was to elucidate the interaction of elevated GGT levels and cholestatic liver disease-induced bone loss. METHODS Wistar rats were divided into three groups: sham-operated control (SO) rats, bile duct ligation (BDL) rats, and anti-GGT antibody-treated BDL rats (AGT). Serum GGT level was measured. Bone mineral density (BMD) was analyzed by dual-energy X-ray absorptiometry. Bone morphometric parameters and microarchitectural properties were determined by micro-computed tomography and histomorphometry of the distal metaphysis of femurs. Alterations of bone metabolism-related factors were evaluated by cytokine array. Effects of GGT on osteoblasts or stromal cells were evaluated by RT-PCR, enzyme activity, and mineralization ability. RESULTS Serum levels of GGT were significantly elevated in the BDL-group. In the BDL group, BMD, bone mass percentage, and osteoblast number were significantly decreased, whereas osteoclast number was significantly increased. These alterations were markedly attenuated in the AGT group. The mRNA levels of vascular endothelial growth factor-A, LPS-induced CXC chemokine, monocyte chemoattractant protein-1, tumor necrosis factor-α interleukin-1β and receptor activator of nuclear factor-kappa B ligand were upregulated, and those of interferon-γ and osteoprotegerin were downregulated in the GGT-treated stromal cells. Furthermore, GGT inhibited mineral nodule formation and expression of alkaline phosphatase and bone sialo-protein in osteoblastic cells. CONCLUSION Our results indicate that elevated GGT level is involved in hepatic osteodystrophy through secretion of bone resorbing factor from GGT-stimulated osteoblasts/bone marrow stromal cells. In addition, GGT also possesses suppressive effects on bone formation. Managing elevated GGT levels by anti-GGT antibody may become a novel therapeutic agent for hepatic osteodystrophy in chronic liver diseases.
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Affiliation(s)
- Yusuke Kawazoe
- Department of Oral and Maxillofacial Pathobiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Mutsumi Miyauchi
- Department of Oral and Maxillofacial Pathobiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Atsuhiro Nagasaki
- Department of Oral and Maxillofacial Pathobiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Hisako Furusho
- Department of Oral and Maxillofacial Pathobiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Syunryo Yanagisawa
- Department of Oral and Maxillofacial Pathobiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Chea Chanbora
- Department of Oral and Maxillofacial Pathobiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Toshihiro Inubushi
- Department of Oral and Maxillofacial Pathobiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Hideyuki Hyogo
- Department of Medicine and Molecular Science, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Takashi Nakamoto
- Department of Oral and Maxillofacial Radiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Keiko Suzuki
- Department of Pharmacology, School of Dentistry, Showa University, Tokyo, Japan
| | - Sawako Moriwaki
- Biobank Omics Unit, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - Susumu Tazuma
- Departments of General Internal Medicine, Hiroshima University Hospital, Hiroshima, Japan
| | - Shumpei Niida
- Biobank Omics Unit, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - Takashi Takata
- Department of Oral and Maxillofacial Pathobiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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15
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Morita T, Yamazaki Y, Fujiharu C, Ishii T, Seto M, Nishinoue N, Sasaki Y, Kawato T, Motohashi M, Maeno M. Serum γ-glutamyltransferase level is associated with periodontal disease independent of drinking habits in Japanese adults. Med Sci Monit 2014; 20:2109-16. [PMID: 25360830 PMCID: PMC4226313 DOI: 10.12659/msm.891204] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background Non-alcoholic fatty liver disease is considered a hepatic manifestation of metabolic syndrome. Periodontal disease is a mild chronic inflammatory disease with systemic effects, and many studies have indicated an association between metabolic syndrome and periodontitis. In the present study, we investigated the relationship between periodontitis and liver biochemical parameters according to alcohol drinking habits through a cross-sectional study based on data from Japanese people in occupational settings. Material and Methods The subjects were 1510 employees (1218 males, 292 females, mean age 50.4 years) who underwent dental and medical checkups in 2012. Associations between the presence of periodontal pockets and serum levels of liver biochemical parameters were assessed. Results Alanine aminotransferase (ALT) and γ-glutamyltransferase (GGT) levels were higher in subjects with than without periodontal pockets. Multiple logistic regression analysis (adjusting for age, gender, cigarette smoking, and alcohol drinking habits, and components of metabolic syndrome) with GGT or ALT as the dependent variable revealed that there was a significant association between periodontal pockets and GGT (odds ratio, OR=1.48), but not ALT. Similar associations were observed when an analysis was performed according to the presence or absence of alcohol drinking habits; the OR was higher in subjects without (OR=1.84) than with drinking habits (OR=1.41). Conclusions The presence of periodontal pockets was associated with serum levels of GGT, a liver biochemical parameter, in Japanese adults with no drinking habit, suggesting that periodontal disease is associated with liver function, independent of alcohol ingestion.
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Affiliation(s)
| | | | | | | | - Misae Seto
- Health Care Center, Lion Corporation, Tokyo, Japan
| | | | - Yoshiyuki Sasaki
- Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takayuki Kawato
- Department of Oral Health Sciences, Nihon University School of Dentistry, Tokyo, Japan
| | - Masafumi Motohashi
- Department of Oral Health Sciences, Nihon University School of Dentistry, Tokyo, Japan
| | - Masao Maeno
- Department of Oral Health Sciences, Nihon University School of Dentistry, Tokyo, Japan
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16
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Ito R, Ihara H, Okada T, Ikeda Y. 1α,25-Dihydroxyvitamin D3 enhances γ-glutamyl transpeptidase activity in LLC-PK1 porcine kidney epithelial cells. Mol Med Rep 2014; 10:2111-5. [PMID: 25109309 DOI: 10.3892/mmr.2014.2436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 11/15/2013] [Indexed: 11/05/2022] Open
Abstract
Mammalian γ-glutamyl transpeptidase (GGT) is expressed most highly in the kidney and serves to recover the constituent amino acids of glutathione in the proximal tubules. Serum GGT is used as a marker for obstructive jaundice and alcoholic liver disease and it has been reported that urinary GGT is a potential marker for bone resorption. The present study investigated the effect of derivatives of vitamin D3 on GGT activity in LLC-PK1 porcine renal tubular epithelial cells in order to analyze the biochemical basis of bone metabolism-associated alterations in GGT activity in the kidney. In the presence of 1α,25-dihydroxyvitamin D3 [1,25(OH)2VD3], GGT activity was observed to be significantly increased in LLC-PK1 cells, with an increase in GGT activity also found in the cell medium. While the stimulatory effect of 1-OH-VD3 was similar to that of 1,25(OH)2VD3, vitamin D3 and 25-OH-VD3 had no effect on GGT activity. The increased GGT activity caused by 1,25(OH)2VD3 in LLC-PK1 cells was the result of long-term stimulation of the cells, in contrast to the GGT-induced increase in alkaline phosphatase, which is more transient. Polymerase chain reaction analysis revealed that the 1,25(OH)2VD3‑induced increase in GGT activity was due to prolonged GGT turnover, rather than increased GGT expression, as no increase in GGT mRNA expression was observed. Thus, it is likely that the expression of GGT is not entirely constitutive in the kidney, but is altered under certain conditions, including under hormonal regulation.
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Affiliation(s)
- Ritsu Ito
- Division of Molecular Cell Biology, Department of Biomolecular Sciences, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Hideyuki Ihara
- Division of Molecular Cell Biology, Department of Biomolecular Sciences, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Takahiro Okada
- Division of Molecular Cell Biology, Department of Biomolecular Sciences, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Yoshitaka Ikeda
- Division of Molecular Cell Biology, Department of Biomolecular Sciences, Faculty of Medicine, Saga University, Saga 849-8501, Japan
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17
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Kim BJ, Baek S, Ahn SH, Kim SH, Jo MW, Bae SJ, Kim HK, Park GM, Kim YH, Lee SH, Kim GS, Choe J, Koh JM. A higher serum gamma-glutamyl transferase level could be associated with an increased risk of incident osteoporotic fractures in Korean men aged 50 years or older. Endocr J 2014; 61:257-63. [PMID: 24366218 DOI: 10.1507/endocrj.ej13-0463] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Oxidative stress has detrimental effects on bone metabolism, and gamma-glutamyl transferase (GGT) is known to play an important role in the generation of free radical species through the extra-cellular hydrolysis of glutathione, the main cellular antioxidant. We performed a large longitudinal study with an average follow-up period of 3 years to investigate the association between baseline serum GGT levels and the development of future osteoporotic fractures (OFs) in men. A total of 16,036 Korean men aged 50 years or older who had undergone comprehensive routine health examinations were enrolled. Incident fractures at osteoporosis-related sites (e.g., hip, spine, distal radius, and proximal humerus) that occurred after baseline examinations were identified from the nationwide claims database of the Health Insurance Review and Assessment Service of Korea using selected ICD-10 codes. Among the study subjects, 156 cases (1.0%) developed incident OFs during the study period. The event rate was 32.7 (95% CI = 28.0-38.3) per 10,000 person-years. Multivariable adjusted Cox proportional hazard analyses adjusted for age, body mass index, lifestyle factors, and medical and drug histories revealed that the hazard ratio per standard deviation increase of the baseline GGT levels for the development of incident fractures was 1.115 (95% CI = 1.011-1.230). These data provide the first epidemiological evidence, in support of previous in vitro and animal studies, of the harmful effects of GGT on bone metabolism, and indicate that the serum GGT level may be a useful biomarker of poor bone health outcomes in men.
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Affiliation(s)
- Beom-Jun Kim
- Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, 138-736 Seoul, Korea
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Bains W. Transglutaminse 2 and EGGL, the protein cross-link formed by transglutaminse 2, as therapeutic targets for disabilities of old age. Rejuvenation Res 2013; 16:495-517. [PMID: 23968147 PMCID: PMC3869435 DOI: 10.1089/rej.2013.1452] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 08/22/2013] [Indexed: 12/17/2022] Open
Abstract
Aging of the extracellular matrix (ECM), the protein matrix that surrounds and penetrates the tissues and binds the body together, contributes significantly to functional aging of tissues. ECM proteins become increasingly cross-linked with age, and this cross-linking is probably important in the decline of the ECM's function. This article reviews the role of ε-(γ-glutamyl)-lysine (EGGL), a cross-link formed by transglutaminase enzymes, and particularly the widely expressed isozyme transglutaminase 2 (TG2), in the aging ECM. There is little direct data on EGGL accumulation with age, and no direct evidence of a role of EGGL in the aging of the ECM with pathology. However, several lines of circumstantial evidence suggest that EGGL accumulates with age, and its association with pathology suggests that this might reflect degradation of ECM function. TG activity increases with age in many circumstances. ECM protein turnover is such that some EGGL made by TG is likely to remain in place for years, if not decades, in healthy tissue, and both EGGL and TG levels are enhanced by age-related diseases. If further research shows EGGL does accumulate with age, removing it could be of therapeutic benefit. Also reviewed is the blockade of TG and active removal of EGGL as therapeutic strategies, with the conclusion that both have promise. EGGL removal may have benefit for acute fibrotic diseases, such as tendinopathy, and for treating generalized decline in ECM function with old age. Extracellular TG2 and EGGL are therefore therapeutic targets both for specific and more generalized diseases of aging.
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Affiliation(s)
- William Bains
- SRF Laboratory, Department of Chemical Engineering and Biotechnology, University of Cambridge , Cambridge, United Kingdom
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Castellano I, Merlino A. Gamma-Glutamyl Transpeptidases: Structure and Function. GAMMA-GLUTAMYL TRANSPEPTIDASES 2013. [DOI: 10.1007/978-3-0348-0682-4_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Abstract
The present study evaluated the prebiotic effect of a standardised aqueous extract of Anoectochilus formosanus (SAEAF) and its effects on osteoporosis in ovariectomised (OVX) rats. The OVX rats were randomly divided into five groups and orally treated with water, SAEAF (200 and 400 mg/kg daily) and inulin (400 mg/kg daily) for 12 weeks. The sham group was orally treated with water. The SAEAF treatment enhanced the number of faecal bifidobacteria in OVX rats. The results of a Ca-balance experiment showed that SAEAF increased apparent Ca absorption and retention. The OVX rats were killed after SAEAF treatment lasting 12 weeks. The SAEAF decreased the caecal pH values and increased the caecal wall weight, caecal mucosa calbindin-D9k mRNA expression, free-Ca concentration and levels of SCFA in the caecum. The mineral content, density and biomechanical strength of bones were lower in OVX rats than the sham group, but these bone losses were prevented by SAEAF administration. Microtomography scanning showed that the SAEAF-treated rats had higher trabecular bone volume than the OVX rats. These results suggest that SAEAF prevented bone loss associated with ovarian hormone deficiency in the rats.
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Kaneko K, Ito M, Fumoto T, Fukuhara R, Ishida J, Fukamizu A, Ikeda K. Physiological function of the angiotensin AT1a receptor in bone remodeling. J Bone Miner Res 2011; 26:2959-66. [PMID: 21887703 DOI: 10.1002/jbmr.501] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In order to determine whether the renin-angiotensin system (RAS) has any physiologic function in bone metabolism, mice lacking the gene encoding the major angiotensin II receptor isoform, AT1a, were studied using micro CT scanning, histomorphometric, and biochemical techniques. Three-dimensional (3D) micro CT analysis of the tibial metaphysis revealed that both male and female AT1a knockout mice exhibited an increased trabecular bone volume along with increased trabecular number and connectivity. Histomorphometric analysis of the tibial metaphysis indicated that the parameters of bone formation as well as resorption were increased, which was also supported by elevated serum osteocalcin and carboxy-terminal collagen crosslink (CTX) concentrations in the AT1a-deficient mice. Osteoclastogenesis and osteoblastogenesis assays in ex vivo cultures, however, did not reveal any intrinsic alterations in the differentiation potential of AT1a-deficient cells. Quantitative RT-PCR using RNA isolated from the tibia and femur revealed that the receptor activator of NF-κB ligand (RANKL)/osteoprotegerin (OPG) ratio and the expression of stromal cell-derived factor (SDF)1α were increased, whereas that of SOST was decreased in AT1a-deficient bone, which may account for the increased bone resorption and formation, respectively. AT1a-deficient mice also displayed a lean phenotype with reduced serum leptin levels. They maintained high bone mass with advancing age, and were protected from bone loss induced by ovariectomy. Collectively, the data suggest that RAS has a physiologic function in bone remodeling, and that signaling through AT1a negatively regulates bone turnover and bone mass.
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Affiliation(s)
- Keiko Kaneko
- Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology (NCGG), Aichi, Japan
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22
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West MB, Wickham S, Quinalty LM, Pavlovicz RE, Li C, Hanigan MH. Autocatalytic cleavage of human gamma-glutamyl transpeptidase is highly dependent on N-glycosylation at asparagine 95. J Biol Chem 2011; 286:28876-28888. [PMID: 21712391 PMCID: PMC3190695 DOI: 10.1074/jbc.m111.248823] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 06/27/2011] [Indexed: 12/26/2022] Open
Abstract
γ-Glutamyl transpeptidase (GGT) is a heterodimeric membrane enzyme that catalyzes the cleavage of extracellular glutathione and other γ-glutamyl-containing compounds. GGT is synthesized as a single polypeptide (propeptide) that undergoes autocatalytic cleavage, which results in the formation of the large and small subunits that compose the mature enzyme. GGT is extensively N-glycosylated, yet the functional consequences of this modification are unclear. We investigated the effect of N-glycosylation on the kinetic behavior, stability, and functional maturation of GGT. Using site-directed mutagenesis, we confirmed that all seven N-glycosylation sites on human GGT are modified by N-glycans. Comparative enzyme kinetic analyses revealed that single substitutions are functionally tolerated, although the N95Q mutation resulted in a marked decrease in the cleavage efficiency of the propeptide. However, each of the single site mutants exhibited decreased thermal stability relative to wild-type GGT. Combined mutagenesis of all N-glycosylation sites resulted in the accumulation of the inactive propeptide form of the enzyme. Use of N-glycosylation inhibitors demonstrated that binding of the core N-glycans, not their subsequent processing, is the critical glycosylation event governing the autocleavage of GGT. Although N-glycosylation is necessary for maturation of the propeptide, enzymatic deglycosylation of the mature wild-type GGT does not substantially impact either the kinetic behavior or thermal stability of the fully processed human enzyme. These findings are the first to establish that co-translational N-glycosylation of human GGT is required for the proper folding and subsequent cleavage of the nascent propeptide, although retention of these N-glycans is not necessary for maintaining either the function or structural stability of the mature enzyme.
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Affiliation(s)
- Matthew B West
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104 and
| | - Stephanie Wickham
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104 and
| | - Leslie M Quinalty
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104 and
| | - Ryan E Pavlovicz
- Biophysics Program, College of Pharmacy, Ohio State University, Columbus, Ohio 43210
| | - Chenglong Li
- Biophysics Program, College of Pharmacy, Ohio State University, Columbus, Ohio 43210; Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, Ohio State University, Columbus, Ohio 43210
| | - Marie H Hanigan
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104 and.
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23
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Ito M. Recent progress in bone imaging for osteoporosis research. J Bone Miner Metab 2011; 29:131-40. [PMID: 21301898 DOI: 10.1007/s00774-010-0258-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 12/27/2010] [Indexed: 01/28/2023]
Abstract
Advances in bone imaging techniques have provided tools for analyzing bone structure at the macro-, micro- and nano-level. Quantitative assessment of macrostructure can be achieved using dual X-ray absorptiometry (DXA) and quantitative computed tomography (QCT), particularly volumetric quantitative CT (vQCT). In vivo quantitative techniques for assessing the microstructure of trabecular bone non-invasively and non-destructively include high-resolution CT (HR-CT) and high-resolution magnetic resonance (HR-MR). Compared with MR imaging, CT-based techniques have the advantage of directly visualizing the bone in the axial skeleton, with high spatial resolution, but the disadvantage of delivering a considerable radiation dose. Micro-CT (μCT), which provides a higher resolution of the microstructure and is principally applicable in vitro, has undergone technological advances such that it is now able to elucidate the physiological skeletal change mechanisms associated with aging and determine the effects of therapeutic intervention on the bone microstructure. In particular, synchrotron μCT (SR-CT) provides a more detailed view of trabecular structure at the nano-level. For the assessment of hip geometry, DXA-based hip structure analysis (HSA) and CT-based HSA have been developed. DXA-based HSA is a convenient tool for analyzing biomechanical properties and for assuming cross-sectional hip geometry based on two-dimensional (2D) data, whereas CT-based HSA provides these parameters three-dimensionally in robust relationship with biomechanical properties, at the cost of greater radiation exposure and the lengthy time required for the analytical procedure. Further progress in bone imaging technology is promising to bring new aspects of bone structure in relation to bone strength to light, and to establish a means for analyzing bone structural properties in the everyday clinical setting.
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Affiliation(s)
- Masako Ito
- Department of Radiology, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan.
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Cappelli S, Epistolato MC, Vianello A, Mazzone A, Glauber M, Franzini M, Ottaviano V, Pompella A, Paolicchi A, Tanganelli P. Aortic valve disease and gamma-glutamyltransferase: Accumulation in tissue and relationships with calcific degeneration. Atherosclerosis 2010; 213:385-91. [DOI: 10.1016/j.atherosclerosis.2010.08.063] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 07/30/2010] [Accepted: 08/13/2010] [Indexed: 01/19/2023]
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25
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Shibayama K. [Molecular mechanism of Helicobacter pylori-mediated pathogenesis]. Nihon Saikingaku Zasshi 2009; 63:387-90. [PMID: 19317227 DOI: 10.3412/jsb.63.387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Keigo Shibayama
- Department of Bacterial Pathogenesis and Infection Control, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011
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Abstract
BACKGROUND There is little information on the role of bisphosphonates and bone mineral density (BMD) measurements for the follow-up and management of bone loss and fractures in long-term kidney transplant recipients. METHODS To address this question, we retrospectively studied 554 patients who had two BMD measurements after the first year posttransplant and compared outcomes in patients treated, or not with bisphosphonates between the two BMD assessments. Kaplan-Meier survival and stepwise Cox regression analyses were performed to examine fracture-free survival rates and the risk-factors associated with fractures. RESULTS The average time (+/-SE) between transplant and the first BMD was 1.2+/-0.05 years. The time interval between the two BMD measurements was 2.5+/-0.05 years. There were 239 and 315 patients in the no-bisphosphonate and bisphosphonate groups, respectively. Treatment was associated with significant preservation of bone loss at the femoral neck (HR 1.56, 95% CI 1.21-2.06, P=0.0007). However, there was no association between bone loss at the femoral neck and fractures regardless of bisphosphonate therapy. Stepwise Cox regression analyses showed that type-1 diabetes, baseline femoral neck T-score, interleukin-2 receptor blockade, and proteinuria (HR 2.02, 0.69, 0.4, 1.23 respectively, P<0.01), but not bisphosphonates, were associated with the risk of fracture. CONCLUSIONS Bisphosphonates may prevent bone loss in long-term kidney transplant recipients. However, these data suggest a limited role for the initiation of therapy after the first posttransplant year to prevent fractures.
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The human gamma-glutamyltransferase gene family. Hum Genet 2008; 123:321-32. [PMID: 18357469 DOI: 10.1007/s00439-008-0487-7] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Accepted: 03/06/2008] [Indexed: 10/22/2022]
Abstract
Assays for gamma-glutamyl transferase (GGT1, EC 2.3.2.2) activity in blood are widely used in a clinical setting to measure tissue damage. The well-characterized GGT1 is an extracellular enzyme that is anchored to the plasma membrane of cells. There, it hydrolyzes and transfers gamma-glutamyl moieties from glutathione and other gamma-glutamyl compounds to acceptors. As such, it has a critical function in the metabolism of glutathione and in the conversion of the leukotriene LTC4 to LTD4. GGT deficiency in man is rare and for the few patients reported to date, mutations in GGT1 have not been described. These patients do secrete glutathione in urine and fail to metabolize LTC4. Earlier pre-genome investigations had indicated that besides GGT1, the human genome contains additional related genes or sequences. These sequences were given multiple different names, leading to inconsistencies and confusion. Here we systematically evaluated all human sequences related to GGT1 using genomic and cDNA database searches and identified thirteen genes belonging to the extended GGT family, of which at least six appear to be active. In collaboration with the HUGO Gene Nomenclature Committee (HGNC) we have designated possible active genes with nucleotide or amino acid sequence similarity to GGT1, as GGT5 (formerly GGL, GGTLA1/GGT-rel), GGT6 (formerly rat ggt6 homologue) and GGT7 (formerly GGTL3, GGT4). Two loci have the potential to encode only the light chain portion of GGT and have now been designated GGTLC1 (formerly GGTL6, GGTLA4) and GGTLC2. Of the five full-length genes, three lack of significant nucleotide sequence homology but have significant (GGT5, GGT7) or very limited (GGT6) amino acid similarity to GGT1 and belong to separate families. GGT6 and GGT7 have not yet been described, raising the possibility that leukotriene synthesis, glutathione metabolism or gamma-glutamyl transfer is regulated by their, as of yet uncharacterized, enzymatic activities. In view of the widespread clinical use of assays that measure gamma-glutamyl transfer activity, this would appear to be of significant interest.
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Guo Y, Yang TL, Pan F, Xu XH, Dong SS, Deng HW. Molecular genetic studies of gene identification for osteoporosis. Expert Rev Endocrinol Metab 2008; 3:223-267. [PMID: 30764094 DOI: 10.1586/17446651.3.2.223] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This review comprehensively summarizes the most important and representative molecular genetics studies of gene identification for osteoporosis published up to the end of September 2007. It is intended to constitute a sequential update of our previously published reviews covering the available data up to the end of 2004. Evidence from candidate gene-association studies, genome-wide linkage and association studies, as well as functional genomic studies (including gene-expression microarray and proteomics) on osteogenesis and osteoporosis, are reviewed separately. Studies of transgenic and knockout mice models relevant to osteoporosis are summarized. The major results of all studies are tabulated for comparison and ease of reference. Comments are made on the most notable findings and representative studies for their potential influence and implications on our present understanding of genetics of osteoporosis. The format adopted by this review should be ideal for accommodating future new advances and studies.
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Affiliation(s)
- Yan Guo
- a The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Tie-Lin Yang
- a The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Feng Pan
- a The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Xiang-Hong Xu
- a The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Shan-Shan Dong
- a The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Hong-Wen Deng
- b The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China and Departments of Orthopedic Surgery and Basic Medical Sciences, University of Missouri - Kansas City, Kansas City, MO 64108, USA.
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Johnson KA, Yao W, Lane NE, Naquet P, Terkeltaub RA. Vanin-1 pantetheinase drives increased chondrogenic potential of mesenchymal precursors in ank/ank mice. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 172:440-53. [PMID: 18187567 DOI: 10.2353/ajpath.2008.070753] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Widespread endochondral and intramembranous ectopic bone formation is mediated by extracellular PP(i) deficiency that develops in ank/ank mice. Herein we report on the rapid condensation into chondrogenic nodules of cultured ank/ank bone marrow stromal cells (BMSCs). We compared the roles of increased chondrogenic potential versus altered osteoblast function in the ank/ank phenotype. To do so, we crossbred ank/ank mice with mice lacking Vanin-1 pantetheinase, which inhibits synthesis of the chondrogenesis regulator glutathione, since we observed increased Vanin-1 expression and pantetheinase activity and decreased glutathione in ank/ank BMSCs. Vnn1(-/-) BMSCs demonstrated delayed chondrogenesis mediated by increased glutathione. Moreover, increased chondrogenesis of ank/ank BMSCs and increased chondrogenic transdifferentiation and calcification by ank/ank aortic smooth muscle cells and explants were corrected by Vanin-1 knockout. Osteoblastogenesis was accelerated in ank/ank mesenchymal stem cells. However, in cultured ank/ank osteoblasts, Vanin-1 knockout actually increased specific alkaline phosphatase activity and lowered extracellular PP(i), and did not correct increased calcification. Moreover, Vanin-1 knockout failed to correct the ank/ank skeletal soft tissue phenotype. Therefore, ank/ank periskeletal soft tissue calcification appears more dependent on altered osteoblastic function than enhanced chondrogenic potential and is not dependent on Vanin-1; however, Vanin-1 regulates chondrogenesis via glutathione metabolism and is critical for accelerated chondrogenesis of ank/ank mesenchymal precursors and P(i) donor-driven chondrogenic transdifferentiation and calcification of aortic smooth muscle cells.
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Affiliation(s)
- Kristen A Johnson
- Department of Medicine, University of California San Diego, San Diego, CA 92161, USA
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Ishizuka Y, Moriwaki S, Kawahara-Hanaoka M, Uemura Y, Serizawa I, Miyauchi M, Shibata S, Kanaya T, Takata T, Taniguchi N, Niida S. Treatment with anti-gamma-glutamyl transpeptidase antibody attenuates osteolysis in collagen-induced arthritis mice. J Bone Miner Res 2007; 22:1933-42. [PMID: 17680722 DOI: 10.1359/jbmr.070726] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED The effectiveness of a new antibody treatment on arthritis-associated osteolysis was studied by using CIA mice. GGT, a newly identified bone-resorbing factor, was upregulated in arthritic joints. We generated monoclonal antibodies against GGT and injected them into CIA mice. Mice treated with antibodies showed a reduction in osteoclast number and bone erosion. INTRODUCTION Gamma-glutamyl transpeptidase (GGT) acts as a bone-resorbing factor that stimulates osteoclast formation. GGT expression has been detected in active lymphocytes that accumulate at inflammation sites, such as rheumatoid arthritis (RA). We hypothesize that GGT is an effective target for suppression of arthritis-related osteoclastogenesis and joint destruction. Here, we describe the therapeutic effect of neutralizing antibodies against GGT on joint destruction using a collagen-induced arthritis (CIA) mouse model. MATERIALS AND METHODS GGT expression in the synovium of RA patients and CIA mice was determined by immunohistochemistry and RT-PCR. Monoclonal antibodies were generated against recombinant human GGT (GGT-mAbs) using BALB/c mice. Antibody treatment was performed by intraperitoneal injections of GGT-mAbs into CIA mice. Effects of antibody treatment on arthritis and bone erosion were evaluated by incidence score, arthritis score, and histopathological observations. The role of GGT in osteoclast development was examined by using the established osteoclastogenic culture system. RESULTS GGT expression was significantly upregulated in inflamed synovium. Immunohistochemistry revealed that GGT was present in lymphocytes, plasma cells, and macrophages, as well as capillaries. Injection of GGT-mAbs significantly decreased the number of osteoclasts and attenuated the severity of joint destruction in CIA mice. In vitro examination showed that GGT enhanced RANKL-dependent osteoclast formation. GGT stimulated the expression of RANKL in osteoblasts and its receptor RANK in osteoclast precursors, respectively. CONCLUSIONS This study indicates that inflamed synovial tissue-derived GGT acts as a risk factor for joint destruction and that the antibody-mediated inhibition of GGT significantly decreases osteoclast number and bone erosion in CIA mice. GGT antagonists might be novel therapeutic agents for attenuating joint destruction in RA patients.
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Pompella A, Corti A, Paolicchi A, Giommarelli C, Zunino F. Gamma-glutamyltransferase, redox regulation and cancer drug resistance. Curr Opin Pharmacol 2007; 7:360-6. [PMID: 17613273 DOI: 10.1016/j.coph.2007.04.004] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Revised: 04/16/2007] [Accepted: 04/26/2007] [Indexed: 01/09/2023]
Abstract
Gamma-glutamyltransferase, a key enzyme of GSH metabolism, can modulate crucial redox-sensitive functions, such as antioxidant/antitoxic defences and cellular proliferative/apoptotic balance, with potential implications in tumour progression and drug resistance. Recent studies have elucidated the mechanisms of GGT involvement in various pathological processes suggesting its potential role as therapeutic target and diagnostic/prognostic marker.
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Affiliation(s)
- Alfonso Pompella
- Dipartimento di Patologia Sperimentale, Università di Pisa, Scuola MedicaVia Roma 55, 56126 Pisa, Italy
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