liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
Clinical significance of bone alkaline phosphatase isoforms, including the novel B1x isoform, in mild to moderate chronic kidney disease
Linköping University, Department of Medicine and Care, Nephrology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Nephrology.
Linköping University, Department of Medicine and Care, Nephrology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Nephrology UHL.
Linköping University, Department of Medicine and Care, Nephrology. Linköping University, Faculty of Health Sciences.
Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
2009 (English)In: NEPHROLOGY DIALYSIS TRANSPLANTATION, ISSN 0931-0509, Vol. 24, no 11, 3382-3389 p.Article in journal (Refereed) Published
Abstract [en]

Background. Mineral bone disorder (MBD) is a common complication of chronic kidney disease (CKD) even during the early stages. Bone alkaline phosphatase (BALP) is a marker of bone fort-nation and plays a pivotal role in the mineralization process. Three BALP isoforms (B/I, B1 and B2) have been identified in healthy individuals and a fourth isoform (B1x) has been discovered in serum from dialysis patients. We investigated these BALP isoforms, type I procollagen intact amino-terminal propeptide (PINP), carboxy-terminal telopeptide of type I collagen (CTX) and tartrate-resistant acid phosphatase isoform 5b (TRACP5b), as well as bone mineral density (BMD) in predialysis CKD patients. Methods. PINP, CTX, TRACP5b and BALP isoforms were analysed in serum from 46 patients within CKD stages 3-5. BMD was determined by dual-energy x-ray absorptiometry. Results. PINP, TRACP5b and the BALP isoforms, B/I, B1 and B2, were independent predictors of total hip BMD in all patients. Furthermore, B/I predicted osteopaenia in the hip and in the distal 1/3 of the radius in CKD stage 3. The B1x isoform was detected in nine patients (20%), who had lower GFR, higher phosphate and calcium x phosphate product. Conclusion. We found an association of BALP isoforms and other markers of bone turnover with total hip BMD, which predominantly comprises trabecular bone. The association of the new BALP isoform B1x with risk factors for vascular calcification leads us to hypothesize a possible role for B1x in this process. The significance of the BALP isoforms in CKD remains to be further explored in experimental and clinical settings in conjunction with bone histomorphometry.

Place, publisher, year, edition, pages
2009. Vol. 24, no 11, 3382-3389 p.
Keyword [en]
alkaline phosphatase, bone mineral density, bone turnover, mineral bone disorder, predialysis
National Category
Medical and Health Sciences
URN: urn:nbn:se:liu:diva-52373DOI: 10.1093/ndt/gfp300OAI: diva2:282144
Available from: 2009-12-18 Created: 2009-12-18 Last updated: 2014-11-06
In thesis
1. Bone alkaline phosphatase isoforms in chronic kidney disease: mineral and bone disorder
Open this publication in new window or tab >>Bone alkaline phosphatase isoforms in chronic kidney disease: mineral and bone disorder
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Chronic kidney disease (CKD) is associated with increased mortality and cardiovascular complications. Disturbances in mineral metabolism occur early <luring the course of CKD and several components of the CKD-mineral and bone disorder (CKD-MBD) are independent predictors of mortality. Alkaline phosphatase (ALP) is necessary for skeletal mineralization and is also involved in the process of vascular calcification. In recent years, ALP has evolved as a strong predictor of mortality in the CKD population. The significant role of ALP in the mineralization process renders it a putative target for the treatment and prevention of vascular calcification. Three circulating isoforms of bone ALP (BALP) have been identified (B/I, B 1, and B2). A fourth isoform, Blx, has been identified exclusively in serum from patients with CKD. The aim of the present thesis was to further elucidate the role ofthe BALP isoforms in CKD with respect to bone abnormalities and vascular calcification.

In study I we identified the novel BALP isoform Blx in 20% of patients with mild to moderate CKD. Blx was associated with lower glomerular filtration rate and higher serum phosphate and calcium x phosphate product, which are risk factors for cardiovascular mortality in CKD. We also identified the BALP isoforms B/I, Bl and B2 as predictors of total hip bone mineral density.

Study II was an experimental study, investigating the role of the BALP isoforms in phosphate induced calcification of human aortic smooth muscle cells (HASMCs). We found that the ALP expressed in HASMCs is exclusively BALP. Phosphate induced calcification of HASMCs was associated with increased BALP isoforms B/I, Blx, and B2 activities, which implies functional differences between the BALP isoforms in HASMC calcification.

In study III we investigated the association of BALP isoforms in serum and histomorphometric parameters of bone in patients on chronic hemodialysis. W e identified the BALP isoform Blx as a novel marker for reduced osteoblastic activity.

Study IV was a prospective cohort study of the association of serum BALP isoforms with aortic calcification and vascular stiffness in prevalent chronic dialysis patients. Blx was associated with baseline and time varying vascular stiffness, determined by pulse wave velocity, but not with calcification of the abdominal aorta. We also found an association of Blx with better event-free survival.

In conclusion, these studies demonstrate that the BALP isoforms, especially isoform Blx, are involved in different aspects of CKD-MBD. This opens up for further research to identify the BALP isoforms as diagnostic markers and possible treatment targets in CKD-MBD.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2014. 89 p.
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1427
National Category
Clinical Medicine
urn:nbn:se:liu:diva-111870 (URN)10.3384/diss.diva-111870 (DOI)978-91-7519-204-8 (print) (ISBN)
Public defence
2014-11-21, Berzeliussalen, Campus US, Linköpings universitet, Linköping, 09:00 (English)
Available from: 2014-11-06 Created: 2014-11-06 Last updated: 2015-06-08Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Haarhaus, MathiasFernström, AndersMagnusson, MartinMagnusson, Per
By organisation
NephrologyFaculty of Health SciencesDepartment of NephrologyDepartment of Nephrology UHLClinical ChemistryDepartment of Clinical Chemistry
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 121 hits
ReferencesLink to record
Permanent link

Direct link