| 1. |
- Grubb, Anders, et al.
(författare)
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Cystatin C, a marker for successful aging and glomerular filtration rate, is not influenced by inflammation.
- 2011
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 71, s. 145-149
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background. The plasma level of cystatin C is a better marker than plasma creatinine for successful aging. It has been assumed that the advantage of cystatin C is not only due to it being a better marker for glomerular filtration rate (GFR) than creatinine, but also because an inflammatory state of a patient induces a raised cystatin C level. However, the observations of an association between cystatin C level and inflammation stem from large cohort studies. The present work concerns the cystatin C levels and degree of inflammation in longitudinal studies of individual subjects without inflammation, who undergo elective surgery. Methods. Cystatin C, creatinine, and the inflammatory markers CRP, serum amyloid A (SAA), haptoglobin and orosomucoid were measured in plasma samples from 35 patients the day before elective surgery and subsequently during seven consecutive days. Results. Twenty patients had CRP-levels below 1 mg/L before surgery and low levels of the additional inflammatory markers. Surgery caused marked inflammation with high peak values of CRP and SAA on the second day after the operation. The cystatin C level did not change significantly during the observation period and did not correlate significantly with the level of any of the four inflammatory markers. The creatinine level was significantly reduced on the first postoperative day but reached the preoperative level towards the end of the observation period. Conclusion. The inflammatory status of a patient does not influence the role of cystatin C as a marker of successful aging, nor of GFR.
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| 2. |
- Ranheimer Östner, Gustav, et al.
(författare)
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Stabilization, Characterization and Selective Removal of Cystatin C Amyloid Oligomers.
- 2013
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 288:23, s. 16438-16450
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Tidskriftsartikel (refereegranskat)abstract
- The pathophysiological process in amyloid disorders usually involves the transformation of a functional monomeric protein via potentially toxic oligomers into amyloid fibrils. The structure and properties of the intermediary oligomers have been difficult to study due to their instability and dynamic equilibrium with smaller and larger species. In hereditary cystatin C amyloid angiopathy, a cystatin C variant is deposited in arterial walls and cause brain hemorrhage in young adults. In the present investigation, we use redox experiments of monomeric cystatin C, stabilized against domain swapping by an intramolecular disulfide bond, to generate stable oligomers (dimers, trimers, tetramers, decamers and high molecular weight oligomers). These oligomers were characterized concerning size by gel filtration, polyacrylamide gel electrophoresis and mass spectrometry, concerning shape by electron and atomic force microscopy, and, concerning function, by assays of their capacity to inhibit proteases. The results showed the oligomers to be highly ordered, domainswapped assemblies of cystatin C and that the oligomers could not build larger oligomers, or fibrils, without domain swapping. The stabilized oligomers were used to induce antibody formation in rabbits. After immunosorption, using immobilized monomeric cystatin C, and elution from columns with immobilized cystatin C oligomers, oligomer-specific antibodies were obtained. These could be used to selectively remove cystatin C dimers from biological fluids containing both dimers and monomers.
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| 3. |
- Östner, Gustav, et al.
(författare)
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High throughput testing of drug library substances and monoclonal antibodies for capacity to reduce formation of cystatin C dimers to identify candidates for treatment of hereditary cystatin C amyloid angiopathy.
- 2011
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 71:8, s. 676-682
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To establish a high-throughput system for testing the ability of drugs or monoclonal antibodies to reduce the in vitro formation of cystatin C dimers to identify substances potentially useful for treatment of patients with hereditary cystatin C amyloid angiopathy (HCCAA). Methods. Various combinations of incubation temperature, time period, guanidinium chloride concentration and concentration of cystatin C monomers were tested in low-volume formats to induce dimer formation of recombinant cystatin C. The extent of dimerization was analysed by gel filtration chromatography and agarose gel electrophoresis. Results. A high-throughput system based upon agarose gel electrophoresis was developed and used to test 1040 drugs in a clinical drug library for their capacity to reduce cystatin C dimer formation in vitro. Seventeen substances reducing dimer formation by more than 30% were identified. A similar system for testing the capacity of monoclonal antibodies against cystatin C to reduce the in vitro formation of cystatin C dimers was also developed and used to test a panel of 12 monoclonal antibodies. Seven antibodies reducing dimer formation by more than 30% were identified and the two most potent, Cyst28 and HCC3, reduced dimerization by 75 and 60%, respectively. Conclusion. We constructed a simple high-throughput system for testing the capacity of drugs and monoclonal antibodies to reduce the in vitro formation of cystatin C dimers and several candidates for treatment of HCCAA could be identified.
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| 4. |
- Östner, Gustav
(författare)
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Molecular Mechanisms in Amyloid Disorders. Novel Treatment Options in Hereditary Cystatin C Amyloid Angiopathy.
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The pathophysiological process in Alzheimer’s disease and other amyloid disorders usually involves the transformation of a soluble monomeric protein via potentially toxic oligomers into amyloid fibrils. The structure and properties of the intermediary oligomers have been difficult to study due to their instability and dynamic equilibrium with smaller and larger species. This has hampered the development of a deeper understanding of the molecular pathophysiology of the disorders and strategies for their treatment. In hereditary cystatin C amyloid angiopathy (HCCAA), a cystatin C variant is deposited in arterial walls and causes brain hemorrhage in young adults. Although carriers of the cystatin C variant may be easily identified by genetic testing, no treatments are available. In the present investigation, redox experiments involving a recombinant double-cysteine mutant of cystatin C were used to generate stable oligomers (dimers, trimers, tetramers, decamers and high-molecular-weight oligomers) and these were characterised concerning size, shape and function. The results showed the oligomers to be highly ordered, domain-swapped assemblies of cystatin C and that the oligomers could not build larger oligomers, or fibrils, without domain swapping. The stabilised oligomers were used to induce antibody formation in rabbits. Oligomer-specific antibodies were obtained and these could be used to selectively remove cystatin C dimers from biological fluids containing both dimers and monomers. A miniaturised high-throughput system was developed and used to test 12 monoclonal antibodies and 1040 drugs in a clinical drug library for their capacity to reduce cystatin C dimer formation in vitro. Several candidates for treatment of HCCAA could be identified. In a different set of patients, scheduled for elective surgery, the plasma levels of cystatin C, creatinine and four inflammatory markers were studied in order to investigate the influence of inflammation on cystatin C, to evaluate its usefulness as a marker of glomerular filtration rate (GFR, ‘kidney function’). The cystatin C level did not change significantly during the observation period (seven days) and did not correlate with the level of any of the four inflammatory markers, and thus, the inflammatory status of a patient does not influence the role of cystatin C as a marker of GFR.
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