Cystatin C, a marker for successful aging and glomerular filtration rate, is not influenced by inflammation

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.

Anders Grubb1, Jonas Björk2, Ulf Nyman3, Joanna Pollak1,5, Johan Bengzon4, Gustav Östner1 & Veronica Lindström1
Department of Clinical Chemistry, Lund University Hospital, Lund, Sweden

Competence Centre for Clinical Research, Lund University Hospital, Lund, Sweden

Department of Radiology, University of Lund, Lasarettet Trelleborg, Trelleborg, Sweden

Department of Neurosurgery, Lund University Hospital, Lund, Sweden

Department of Laboratory Medicine, Nicolaus Copernicus University, Collegium Medicum, Bydgoszcz, Poland