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Nagy E, Sobh MM, Abdalbary M, Elnagar S, Elrefaey R, Shabaka S, Elshabrawy N, Shemies R, Tawfik M, Santos CGS, Barreto FC, El-Husseini A. Is Adynamic Bone Always a Disease? Lessons from Patients with Chronic Kidney Disease. J Clin Med 2022; 11:jcm11237130. [PMID: 36498703 PMCID: PMC9736225 DOI: 10.3390/jcm11237130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 11/28/2022] [Indexed: 12/04/2022] Open
Abstract
Renal osteodystrophy (ROD) is a common complication of end-stage kidney disease that often starts early with loss of kidney function, and it is considered an integral part in management of patients with chronic kidney disease (CKD). Adynamic bone (ADB) is characterized by suppressed bone formation, low cellularity, and thin osteoid seams. There is accumulating evidence supporting increasing prevalence of ADB, particularly in early CKD. Contemporarily, it is not very clear whether it represents a true disease, an adaptive mechanism to prevent bone resorption, or just a transitional stage. Several co-players are incriminated in its pathogenesis, such as age, diabetes mellitus, malnutrition, uremic milieu, and iatrogenic factors. In the present review, we will discuss the up-to-date knowledge of the ADB and focus on its impact on bone health, fracture risk, vascular calcification, and long-term survival. Moreover, we will emphasize the proper preventive and management strategies of ADB that are pivotal issues in managing patients with CKD. It is still unclear whether ADB is always a pathologic condition or whether it can represent an adaptive process to suppress bone resorption and further bone loss. In this article, we tried to discuss this hard topic based on the available limited information in patients with CKD. More studies are needed to be able to clearly address this frequent ROD finding.
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Affiliation(s)
- Eman Nagy
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Mahmoud M. Sobh
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Mohamed Abdalbary
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Sherouk Elnagar
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Rabab Elrefaey
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Shimaa Shabaka
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Nehal Elshabrawy
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Rasha Shemies
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Mona Tawfik
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Cássia Gomes S. Santos
- Department of Internal Medicine, Division of Nephrology, Federal University of Paraná, Curitiba 80060-00, PR, Brazil
| | - Fellype C. Barreto
- Department of Internal Medicine, Division of Nephrology, Federal University of Paraná, Curitiba 80060-00, PR, Brazil
| | - Amr El-Husseini
- Division of Nephrology & Bone and Mineral Metabolism, University of Kentucky, Lexington, KY 40536-0298, USA
- Correspondence: ; Tel.: +1-859-218-0934; Fax: +1-859-323-0232
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Abstract
The term “renal osteodystrophy” encompasses all forms of metabolic bone disease found in dialysis patients. The primary approach to the treatment of renal osteodystrophy in peritoneal dialysis (PD) patients is similar to that in hemodialysis patients. However, the increased prevalence of adynamic bone histology, together with the difficulty in judging calcium balance, the inability to practicably give intravenous vitamin D, and the clearance of vitamin D and parathyroid hormone via dialysate require a different therapeutic approach in PD compared to hemodialysis patients. Clearly, more comparative studies of new agents are needed to find the optimal approach to achieving the K/DOQI guidelines in PD patients. The unique aspects of the approach to renal osteodystrophy in PD patients are the focus of this review.
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Affiliation(s)
- Sharon M. Moe
- Medicine/Nephrology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Ávila-Díaz M, Matos M, García-López E, Prado MDC, Castro-Vázquez F, Ventura MDJ, Dante Amato EG, Paniagua R. Serum Markers of Low-Turnover Bone Disease in Mexican Children with Chronic Kidney Disease Undergoing Dialysis. Perit Dial Int 2020. [DOI: 10.1177/089686080602600112] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BackgroundThe frequency of low-turnover bone disease (LTBD) in patients with chronic kidney disease (CKD) has increased in past years. This change is important because LTBD is associated with bone pain, growth delay, and higher risk for bone fractures and extraosseous calcifications. LTBD is a histological diagnosis. However, serum markers such as parathyroid hormone (PTH) and calcium levels offer a noninvasive alternative for diagnosing these patients.ObjectiveTo describe the prevalence of LTBD in pediatric patients with renal failure undergoing some form of renal replacement therapy, using serum calcium and intact PTH levels as serum markers.MethodsIn this cross-sectional study, 41 children with CKD undergoing dialysis treatment (31 on continuous ambulatory peritoneal dialysis and 10 on hemodialysis) were included. There were no inclusion restrictions with respect to gender, cause of CKD, or dialysis modality. The children were studied as outpatients. The demographic data, CKD course, time on dialysis, phosphate-binding agents, and calcitriol prescription were registered, as well as weight, height, Z-score for height, linear growth rate, and Z-score for body mass index. Serum calcium, phosphorus, aluminum, PTH, alkaline phosphatase, osteocalcin, glucose, creatinine, urea, cholesterol, and triglycerides were measured.ResultsThere were 20 (48.8%) children with both PTH <150 pg/mL and corrected total calcium >10 mg/dL who were classified as having LTBD[(+)]; the remaining 21 (51.2%) children were classified as having no LTBD[(–)]. The LTBD(+) patients were younger (11.2 ± 2.7 vs 13.2 ± 2.4 years, p < 0.01) but they had no differences regarding Z-scores for height. Linear growth in 6 months was less than expected in both groups (-0.15 ± 0.23 cm/month), but the difference between expected and observed growth was higher in the LTBD(+) group (-0.24 ± 0.14 vs –0.07 ± 0.28 cm/mo, p < 0.03). LTBD(+) patients also had lower serum creatinine (8.69± 2.75 vs 11.19 ± 3.17 mg/dL, p < 0.01), higher serum aluminum levels [median (range) 38.4 (9 – 106) vs 28.1 (9 – 62) μg/L, p < 0.05], and lower systolic blood pressure (112.0 ± 10.3 vs 125.0 ±12.9 mmHg, p < 0.015) and diastolic blood pressure (76.0 ± 9.7 vs 84.5 ± 8.2 mmHg, p < 0.017). A significant correlation was found between PTH and alkaline phosphatase ( r = 0.68, p < 0.001), but not between PTH and aluminum.ConclusionThe LTBD(+) biochemical profile was found in 48.8% of the children and was associated with impaired linear growth. Aluminum contamination, evidenced by higher serum aluminum levels, may have had a pathogenic role in these disorders. Higher systolic and diastolic blood pressure levels may be related to higher serum PTH levels.
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Affiliation(s)
- Marcela Ávila-Díaz
- Unidad de Investigación Médica en Enfermedades Nefrológicas, Hospital de Especialidades, Centro Médico Nacional Siglo XXI
| | - Mario Matos
- Departamento de Nefrología, Hospital General, Centro Médico Nacional La Raza
| | - Elvia García-López
- Departamento de Nefrología, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, México DF, México
| | - María-del-Carmen Prado
- Unidad de Investigación Médica en Enfermedades Nefrológicas, Hospital de Especialidades, Centro Médico Nacional Siglo XXI
| | - Florencia Castro-Vázquez
- Departamento de Nefrología, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, México DF, México
| | - María-de-Jesús Ventura
- Unidad de Investigación Médica en Enfermedades Nefrológicas, Hospital de Especialidades, Centro Médico Nacional Siglo XXI
| | - Elia González Dante Amato
- Unidad de Investigación Médica en Enfermedades Nefrológicas, Hospital de Especialidades, Centro Médico Nacional Siglo XXI
| | - Ramón Paniagua
- Unidad de Investigación Médica en Enfermedades Nefrológicas, Hospital de Especialidades, Centro Médico Nacional Siglo XXI
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Leng X, Xu W, Qiao C, Jia X, Long Y, Yang B. New rhodamine B-based chromo-fluorogenic probes for highly selective detection of aluminium(iii) ions and their application in living cell imaging. RSC Adv 2019; 9:6027-6034. [PMID: 35517253 PMCID: PMC9060861 DOI: 10.1039/c8ra09850f] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/03/2019] [Indexed: 11/24/2022] Open
Abstract
Two rhodamine B-based fluorescent probes, BOS1 and BOS2, were designed and synthesized with good yields via the condensation reactions between the o-diaminobenzene modified rhodamine core structure (RBO) and salicylaldehyde derivatives. Both the probes exhibited remarkable absorbance-on and fluorescence-on responses to Al3+ over other metal ions in ethanol–water (1 : 9, v/v) medium via the rhodamine ring-opening approach, which can be used for “naked-eye” Al3+ detection over a broad pH range (5–9). The fluorescence intensities of the probes were linear with the Al3+ ion concentration, resulting in a low limit of detection of 1.839 μM (BOS1) and 1.374 μM (BOS2) for Al3+. In addition, the MTT assays and cell imaging experiments of Al3+ in SGC-7901 living cells demonstrated that the probes had negligible cytotoxicity, and were cell permeable and suitable for sensing Al3+ in biological systems. Two rhodamine B-based fluorescent probes exhibited remarkable absorbance-on and fluorescence-on responses to Al3+, which can be used for biological imaging.![]()
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Affiliation(s)
- Xin Leng
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710127
- China
| | - Wenfeng Xu
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710127
- China
| | - Chengfang Qiao
- Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources
- College of Chemical Engineering and Modern Materials
- Shangluo University
- Shangluo 726000
- China
| | - Xu Jia
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710127
- China
| | - Ying Long
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710127
- China
| | - Bingqin Yang
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710127
- China
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Luo J, Zhou W, Zhou X, Li D, Weng J, Yi Z, Cho SG, Li C, Yi T, Wu X, Li XY, de Crombrugghe B, Höök M, Liu M. Regulation of bone formation and remodeling by G-protein-coupled receptor 48. Development 2009; 136:2747-56. [PMID: 19605502 DOI: 10.1242/dev.033571] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
G-protein-coupled receptor (GPCR) 48 (Gpr48; Lgr4), a newly discovered member of the glycoprotein hormone receptor subfamily of GPCRs, is an orphan GPCR of unknown function. Using a knockout mouse model, we have characterized the essential roles of Gpr48 in bone formation and remodeling. Deletion of Gpr48 in mice results in a dramatic delay in osteoblast differentiation and mineralization, but not in chondrocyte proliferation and maturation, during embryonic bone formation. Postnatal bone remodeling is also significantly affected in Gpr48(-/-) mice, including the kinetic indices of bone formation rate, bone mineral density and osteoid formation, whereas the activity and number of osteoclasts are increased as assessed by tartrate-resistant acid phosphatase staining. Examination of the molecular mechanism of Gpr48 action in bone formation revealed that Gpr48 can activate the cAMP-PKA-CREB signaling pathway to regulate the expression level of Atf4 in osteoblasts. Furthermore, we show that Gpr48 significantly downregulates the expression levels of Atf4 target genes/proteins, such as osteocalcin (Ocn; Bglap2), bone sialoprotein (Bsp; Ibsp) and collagen. Together, our data demonstrate that Gpr48 regulates bone formation and remodeling through the cAMP-PKA-Atf4 signaling pathway.
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Affiliation(s)
- Jian Luo
- The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
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Wei M, Esbaei K, Bargman JM, Oreopoulos DG. Inverse correlation between serum magnesium and parathyroid hormone in peritoneal dialysis patients: a contributing factor to adynamic bone disease? Int Urol Nephrol 2007; 38:317-22. [PMID: 16868704 DOI: 10.1007/s11255-006-0082-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2005] [Indexed: 11/27/2022]
Abstract
BACKGROUND Secondary hyperparathyroidism (SHPTH) is present in many patients with end-stage renal disease (ESRD) and has been linked to uremic bone disease. Parathyroid hormone (PTH) levels are affected by calcium, vitamin D, and phosphorus. Recent data suggests that serum magnesium may also modulate PTH levels. OBJECTIVE The aim of this retrospective study was to investigate the impact of different calcium (Ca) and magnesium (Mg) concentrations of dialysis solutions on serum Mg and serum PTH levels in peritoneal dialysis (PD) patients. PATIENTS AND METHODS Two groups of PD patients-group A (n = 17) on "standard" Ca and Mg dialysis solution (SCa-MgD) (Ca: 1.62 mmol/l, Mg: 0.75 mmol/l and Lactate 35 mmol/l), and group B (n = 29) on "low" Ca and Mg dialysis solution (LCa-MgD) (Ca: 1.25 mmol/l, Mg: 0.25 mmol/l and Lactate 40 mmol/l), on PD for more than 6 months, were studied. Calcium carbonate (CaCO3) was used as the phosphate (P) binder in 87% (40/46) of the patients. Biochemical parameters were evaluated every 1-2 months over 6 months and the mean values were computed. RESULTS No significant differences were found between the two groups in all parameters except for serum Mg and PTH. Serum Mg was higher in SCa-MgD group compared to those in the LCa-MgD group (1.05 +/- 0.19 vs 0.90 +/- 0.23 mmol/l, respectively) and serum PTH was higher in LCa-MgD group compared to those in SCa-MgD group (72.3 +/- 64.2 vs 31.1 +/- 39.0 pmol/l, respectively) even though serum Ca was not different. There was a statistically significant inverse correlation between serum Mg and PTH levels (r = -0.357, p < 0.05). CONCLUSION Serum Mg is lower and serum PTH higher in patients dialyzed with lower Mg concentration dialysis solution compared to those with higher Mg concentration dialysis solution. Our study confirms previous reports that serum Mg may have a suppressive role on PTH synthesis and/or secretion, and thus may play a role in pathogenesis of adynamic bone disease that often develops in patients on chronic PD with high calcium and high magnesium concentrations.
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Affiliation(s)
- Mingxin Wei
- Home Peritoneal Dialysis Unit, University Health Network and University of Toronto, Toronto, Ontario, Canada.
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Iwata Y, Wada T, Yokoyama H, Toyama T, Kitajima S, Okumura T, Hara A, Yamahana J, Nakaya I, Kobayashi M, Kitagawa K, Kokubo S, Yoshimoto K, Shimizu K, Sakai N, Furuichi K, Koshino Y, Takeda S, Takasawa K, Ohta S, Takaeda M, Takaeda C, Kaneko S. Effect of sevelamer hydrochloride on markers of bone turnover in Japanese dialysis patients with low biointact PTH levels. Intern Med 2007; 46:447-52. [PMID: 17443033 DOI: 10.2169/internalmedicine.46.6338] [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: 11/06/2022] Open
Abstract
BACKGROUND In hemodialysis patients, adynamic bone disease has been reported to be closely associated with low levels of parathyroid hormone (PTH) due to exposure to high levels of serum calcium following the administration of calcium carbonate (CaCO3) or vitamin D agents. This study was conducted to clarify the therapeutic effect of a non-calcemic phosphate binder, sevelamer hydrochloride (sevelamer), for hypoparathyroidism in hemodialysis patients with or without diabetes mellitus. METHODS Based on entry criteria, 40 Japanese chronic hemodialysis patients (22 males and 18 females with a mean age of 60.6, 14 diabetic patients and 26 non-diabetic patients) were switched from CaCO3 to sevelamer for 48 weeks. Serum calcium, phosphate, intact (i) PTH and PTH-(1-84) were analyzed. Bone remodeling activity was evaluated by determining intact osteocalcine (iOC), bone-specific alkaline phosphatase (BAP). RESULTS The switch from CaCO3 to sevelamer significantly decreased the serum levels of calcium, resulting in the elevation of iPTH levels from 31+/-18 pg/mL to 95+/-96 pg/mL by 48 weeks. In contrast, serum phosphate levels remained similar to those in patients with CaCO3 treatment. Concomitantly, the levels of BAP and iOC were elevated. Further, these beneficial effects on bone turnover were observed in both diabetic and non-diabetic patients. CONCLUSION Sevelamer reduced the calcium concentration and thereby increased PTH levels, resulting in the improvement of markers of bone turnover. The administration of sevelamer is of therapeutic benefit for the improvement of bone remodeling activity even in hemodialysis patients with diabetes.
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Affiliation(s)
- Yasunori Iwata
- Disease Control and Homeostasis, Kanazawa University Graduate School of Medicine.
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8
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Rocha LA, Higa A, Barreto FC, dos Reis LM, Jorgetti V, Draibe SA, Carvalho AB. Variant of adynamic bone disease in hemodialysis patients: fact or fiction? Am J Kidney Dis 2006; 48:430-6. [PMID: 16931216 DOI: 10.1053/j.ajkd.2006.05.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Accepted: 05/30/2006] [Indexed: 11/11/2022]
Abstract
BACKGROUND Adynamic bone disease is a type of renal osteodystrophy characterized by low bone turnover and paucity of bone cells. It was proposed that a new type of this disease featuring high osteoclastic resorption without parathyroid hormone stimulus and designated adynamic bone disease variant occurs in hemodialysis patients. The present study is designed to evaluate the frequency and characteristics of both diseases in a large series of bone biopsy specimens. METHODS We reviewed 1,160 bone biopsy specimens from hemodialysis patients. Specimens in which adynamic bone disease was diagnosed were selected and categorized as classic or variant based on osteoclastic surface. RESULTS In 218 bone biopsy specimens (18.8%), adynamic bone disease was identified, whereas the variant form was identified in 35 specimens (38.8%). Biopsy specimens categorized as the variant form were from patients who were younger and had greater phosphorus and parathyroid hormone levels. Histologically, the variant form presented greater osteoid volume, fibrosis volume, osteoid surface, osteoblast surface, and eroded surface. Similarly, values for all dynamic parameters were greater in the variant group. Osteoclastic surface correlated with phosphorus level, parathyroid hormone level, and osteoblast surface. Age and osteoblast surface were identified as independent determinants of the variant form. CONCLUSION Adynamic bone disease variant seems to occur in younger hemodialysis patients with greater levels of parathyroid hormone, which acts on cell-covered bone surfaces. It probably is a transitional phase from low- to high-turnover status, rather than a true entity within the spectrum of renal osteodystrophy.
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Affiliation(s)
- Lillian A Rocha
- Nephrology Department, Federal University of São Paulo School of Medicine, Brazil.
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9
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Abstract
Cardiovascular disease and stroke account for 60-70% of all deaths in patients with end-stage renal disease (ESRD), at a risk that is 10-20-fold the age- and sex-matched general population. There is also increased coronary artery calcification and increased cardiovascular mortality in chronic kidney disease (CKD) and dialysis patients compared with the general population. Bone is similarly abnormal in CKD. There is an increased incidence of low bone mass and fractures in dialysis patients compared with the general population. Furthermore, a hip fracture in a dialysis patient is associated with a doubling of the mortality observed in nondialysis patients with a hip fracture. These two problems may be linked, as cross-sectional studies have demonstrated an inverse relationship between osteoporosis and coronary artery calcification in the general population and in ESRD patients. In vitro and ex vivo, there is clear evidence that vascular calcification is an active cell-mediated process, made worse by disorders of mineral metabolism. Many factors known to be associated with cardiovascular disease in CKD patients can directly increase calcification in vitro. In addition, in CKD, there are many mechanisms by which bone may adversely affect vascular calcification including disorders of bone remodelling, altered secretion of parathyroid hormone (PTH), hyperphosphatemia, hypercalcaemia, use of calcium based binders, and excessive vitamin D therapy. The coexistence of vascular risk factors and abnormal bone represent a double threat to the well being of patients with CKD.
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Affiliation(s)
- S M Moe
- Indiana University School of Medicine and Roudebush Veterans Affairs Medical Center, Indianapolis, IN 46202, USA.
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Jorge C, Gil C, Possante M, Silva E, Andrade R, Santos N, Cruz A, Teixeira R, Ferreira A. Bone alkaline phosphatase besides intact parathyroid hormone in hemodialysis patients--any advantage? Nephron Clin Pract 2005; 101:c122-7. [PMID: 16015001 DOI: 10.1159/000086682] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2003] [Accepted: 03/10/2005] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIM Bone alkaline phosphatase (bAP) is known to be an important biochemical marker of bone formation. Through the present study, we intended to find out whether there is any advantage in bAP determination, as a routine biochemical marker, besides intact parathyroid hormone (iPTH) in hemodialysis patients. METHODS In a population of 140 hemodialysis patients, bAP and iPTH were determined on four quarterly consecutive occasions. According to the values of iPTH (pg/ml) and bAP (ng/ml), patients were divided into four groups: group I: iPTH > 200 and bAP > 20, group II: iPTH > 200 and bAP < 20, group III: iPTH < 200 and bAP < 20 and group IV: iPTH < 200 and bAP > 20. Patients with higher serum phosphorus (P) (group A: P > or = 7 mg/dl) were compared with those with lower serum P levels (group B: P < 7 mg/dl). RESULTS The global correlation between iPTH and bAP (total evaluations, n = 503) was 0.32 (p < 0.001). Group IV patients tended to show a slight increase of serum aluminum (sAl) levels, which were 12.48 +/- 5.35 microg/l higher than in the patients from group I (sAl = 9.97 +/- 4.39 microg/l), group II (sAl = 10.86 +/- 4.45 microg/l) or group III (sAl = 10.92 +/- 3.92 microg/l). Significance values (Mann-Whitney) in each group, in comparison with group IV, were the following: group I: 0.004; group II: 0.062; group III: < 0.001. Group A (n = 66) showed higher iPTH levels than group B (n = 430), although bAP and sAl were both similar in these two groups of patients (Mann-Whitney): iPTH (A) = 631.0 +/- 487.7 vs. iPTH (B) = 253.3 +/- 191.6, p < 0.001; bAP (A) = 22.9 +/- 17.4 vs. bAP (B) = 20.4 +/- 13.1, p = n.s.; sAl (A) = 10.2 +/- 3.5 vs. sAl (B) = 10.8 +/- 4.4, p = n.s. For similar Al and bAP values, group A showed a much stronger iPTH/bAP correlation than group B: r = 0.67 (p < 0.001) vs. r = 0.30 (p < 0.001), respectively. CONCLUSION Although iPTH and bAP are frequently in agreement, it seems important to separate parathyroid activity given by iPTH, from bone remodelling reflected by bAP, in the presence of either a higher aluminum exposition or a well-controlled phosphatemia.
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Affiliation(s)
- Cristina Jorge
- Hemodial, Centro de Hemodiálise de Vila Franca de Xira, Vila Franca de Xira, Portugal.
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11
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Martola L, Barany P, Stenvinkel P. Why Do Dialysis Patients Develop a Heart of Stone and Bone of China? Blood Purif 2005; 23:203-10. [PMID: 15809503 DOI: 10.1159/000084890] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2004] [Indexed: 01/09/2023]
Abstract
Vascular calcification is a common complication of end-stage renal disease (ESRD). The mechanisms responsible are complex and have so far been considered to be mainly the result of a passive mechanism due to elevated PO(4) levels and high Ca x PO(4) ion product resulting in saturated plasma. However, recent results suggest that also other features, commonly observed in the uremic milieu, such as chronic inflammation, hyperleptinemia and a dysregulation of various mineral-regulating proteins might also contribute to an enhanced calcification process. Moreover, as an inverse relationship between vascular calcification and bone density has been documented in ESRD, it could be speculated that pathologically low bone remodelling (adynamic bone disease) associated with active vitamin D treatment and low parathyroid hormone (PTH) levels may predispose to ectopic calcification of vessels, valves and heart. As patients with vascular calcification have a higher intake of calcium-containing PO(4) binders, novel, non-calcium containing PO(4) binders may diminish the risk of progressive vascular calcification in this patient group. Further studies are needed to elucidate the respective role of chronic inflammation, hyperleptinemia and PTH-lowering therapies in this fatal complication of ESRD.
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Affiliation(s)
- Leena Martola
- Division of Renal Medicine, Department of Clinical Science, Karolinska University Hospital, Karolinska Institutet, SE-141 86 Stockholm, Sweden
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12
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Yajima A, Ogawa Y, Takahashi HE, Tominaga Y, Inou T, Otsubo O. Changes of bone remodeling immediately after parathyroidectomy for secondary hyperparathyroidism. Am J Kidney Dis 2004; 42:729-38. [PMID: 14520623 DOI: 10.1016/s0272-6386(03)00909-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Successful parathyroidectomy for secondary hyperparathyroidism alleviates bone pain and is followed by the development of hypophosphatemia and hypocalcemia, as well as an increase in bone mineral density. An increase in osteoblast surface (Ob.S/BS) is not observed several months after surgery. In this study, we investigated early bone changes at 1 week after parathyroidectomy and the mechanism underlying an increase in bone mineral density. METHODS Fourteen patients with severe secondary hyperparathyroidism underwent iliac bone biopsy before and 1 week after parathyroidectomy. Changes in histomorphometric parameters, including osteoclast surface (Oc.S/BS), eroded surface (ES/BS), erosion depth (E.De), fibrosis volume (Fb.V/TV), Ob.S/BS, osteoid volume (OV/BV), osteoid surface (OS/BS), and osteoid thickness (O.Th), were investigated. Changes in texture of mineralized bone and osteoid seams were also investigated. RESULTS Oc.S/BS (P < 0.001), ES/BS (P < 0.01), and E.De (P < 0.001) decreased, but Fb.V/TV did not change at 1 week postoperatively. In particular, osteoclasts disappeared in almost all patients. Ob.S/BS (P < 0.001) increased, and cuboidal osteoblasts were proliferating on the trabecular surface where osteoclasts had existed before parathyroidectomy. As a result, newly developed osteoblasts coexisted with fibrous tissue after surgery. OV/BV (P < 0.005), OS/BS (P < 0.005), and O.Th (P < 0.005) increased, with lamellar osteoid volume showing a particular increase. Bone mineralization continued despite the low postoperative serum parathyroid hormone level. CONCLUSION A rapid decrease in serum parathyroid hormone level after parathyroidectomy appears to suppress bone resorption, as well as cause a transient marked increase in bone formation and an increase in normal lamellar osteoid seams.
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Affiliation(s)
- Aiji Yajima
- Department of Nephrology, Towa Hospital, Tokyo, Japan.
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Rašeta N, Kulauzov M, Avram-Šolaja S, Jakovljević B. Bone metabolism in terminal stage of chronic renal insufficiency. SCRIPTA MEDICA 2004. [DOI: 10.5937/scrimed0402067x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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Parfitt AM. Renal bone disease: a new conceptual framework for the interpretation of bone histomorphometry. Curr Opin Nephrol Hypertens 2003; 12:387-403. [PMID: 12815335 DOI: 10.1097/00041552-200307000-00007] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
My purpose in this article is to restore the histologic appraisal of renal bone disease to the mainstream of bone and mineral metabolism from which it has been separated for many years. Historically, both the two major components were found in varying degrees in most patients, although one or other of them often predominated. For more than 15 years bone biopsy has been used almost exclusively to classify individual patients into hyperparathyroid, osteomalacic, mixed and adynamic categories according to rigid non-overlapping criteria, and remarkably few histologic data have been reported. All metabolic bone diseases result from disordered bone remodeling, the physiologic mechanism for replacing bone that has become too old to carry out its mechanical or metabolic functions. Bone remodeling is not directly concerned with the regulation of plasma calcium, which reflects the level of equilibration at quiescent bone surfaces between systemic and bone extracellular fluid set by parathyroid hormone. The separation of remodeling from homeostasis explains the concurrence of increased turnover and decreased plasma calcium in chronic renal failure; it is the homeostatic system, rather than the remodeling system, which is resistant to parathyroid hormone. The effect of mild hyperparathyroidism is a nonspecific increase in bone turnover, of which the best index is the bone formation rate measured by double tetracycline labeling expressed per unit of bone surface. Increased turnover is always accompanied by increased reversible mineral deficit. In prolonged hyperparathyroidism there is also accelerated irreversible bone loss manifested mainly as thinning of cortical bone, detectable in chronic renal failure before any symptoms, due to increased resorption depth on the endocortical surface. In severe hyperparathyroidism resorbed bone is replaced, not by a lesser quantity of normal bone, but by a mixture of vascular fibrous tissue and woven bone, referred to as osteitis fibrosa. In osteomalacia there is increased accumulation of osteoid, due not to increased turnover, but to prolongation of mineralization lag time, which in conjunction with increased thickness, surface and volume of osteoid is diagnostic. Converting histomorphometric data into category assignment discards most of the useful information, which can be retained by two-dimensional representation of severity. For the hyperparathyroid dimension, bone formation rate measured by double tetracycline labeling expressed per unit of bone surface is the most useful although not ideal. For the osteomalacic dimension a mineralization index was constructed that is unaffected by age or race. In patients with osteitis fibrosa, bone formation rate per unit of bone surface and mineralization index were inversely correlated. For the third dimension a structure/formation index was constructed which increases with age in healthy women and shows weak inverse correlation with bone formation rate. The structure/formation index is lower than normal in patients with osteitis fibrosa, and should be useful in the study of osteopenia in chronic renal failure. Bone formation rate is low in osteomalacia, but some patients have subnormal rates through quite a different mechanism. The frequency of this finding has been overestimated for several reasons: failure to exclude atypical osteomalacia (increased surface and volume but not thickness of osteoid), use of inappropriate reference values, and failure to measure the bone formation rate on endocortical and intracortical surfaces. In healthy women bone formation rate can be zero on the cancellous surface alone. Low bone formation rate is sometimes due to diabetes but most often is the expected response to subnormal parathyroid hormone secretion accompanying an excess of calcium, a situation recognized only recently because of improvement in parathyroid hormone assay methodology. Low cancellous bone formation rate should not increase fracture risk because turnover is much lower in the peripheral than in the central skeleton, and all reports of increased fracture risk are flawed or open to different interpretation. Low bone formation rate is associated with reduced skeletal buffering of calcium and increased soft tissue calcification. This is not a new disease needing its own treatment, however, but represents the final stage of skeletal adaptation to a surfeit of calcium. The concept of adynamic bone disease has been harmful by directing attention away from the most important consequence of over-treatment of hyperparathyroidism.
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Affiliation(s)
- A Michael Parfitt
- Division of Endocrinology and Center for Osteoporosis and Metabolic Bone Disease, University of Arkansas for Medical Sciences, Arkansas, USA.
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Abstract
Musculoskeletal problems remain among the main limitations of the quality of life of renal failure patients, in particular of those treated with long-term maintenance dialysis. Renal osteodystrophy continues to receive great attention. The mechanisms of uremic skeletal resistance to parathormone (PTH) are further investigated. The assay used for the dosage of "intact PTH" has been found to detect 7-84 fragments with an inhibitory effect on the action of the whole hormone. A decrease in the density of PTH receptor on osteoblasts is another recently evidenced factor. Investigations of the recently described RANK-RANKL system have demonstrated an increase in serum osteprotegerin levels, which, together with the two above-mentioned abnormalities, may explain bone resistance to PTH. These are important advances in the understanding of renal osteodystrophy as skeletal resistance to PTH appears to play an important part in the pathophysiology of secondary hyperparathyroidism and of adynamic bone disease. Because of this skeletal resistance, it has been recommended for several years that serum PTH level be monitored and kept twofold to threefold above the upper value of the normal level to maintain normal bone turnover in dialysis patients. Relative hypoparathyroidism has recently been found to be associated with increased spontaneous fracture rate and mortality, so this recommendation appears to hold adequate, despite the demonstration that serum PTH levels in this range are a poor predictor of bone turnover and that chronic parathyroid gland hyperplasia is likely to favor parathyroid gland autonomization. Recent publications have insisted on the role that hyperphosphatemia plays not only in the development of secondary hyperparathyroidism, but also of vascular, especially coronary, calcification and as a predictor of mortality. This "silent killer" of uremic patients is one of the main targets for therapeutic intervention. Extensive use of calcium-containing phosphate binders has been recently criticized as calcium overload appears to favor vascular calcification. Sevelaner (RenaGel) is a calcium- and aluminum-free phosphate binder that is an important advance in the management of renal osteodystrophy, especially in patients with extraskeletal calcification and hypercalcemia. The use of vitamin D derivatives has also raised concern because they enhance calcium and phosphorus absorption and reduce bone turnover. New metabolites with fewer hypercalcemic effects have been developed. Calcium-sensing receptor agonists are stimulating interest and are likely to take an important place in the future management of renal osteodystrophy. Uremic myopathy has received recent attention. Impaired muscle capillary oxygen transfer has been identified as a pathophysiologic factor, and progressive resistance training has been shown to improve the condition. Finally, a new entity, nephrogenic fibrosing dermopathy, has been described, which must be distinguished from calciphylaxis and scleromyxedema.
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Affiliation(s)
- Thomas Bardin
- Fédération de Rhumatologie Hôpital Lariboisière, Paris, France.
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