Year : 2009 | Volume
: 20 | Issue : 6 | Page : 1015--1017
Value of serum cystatin C as a marker of renal function in the early post kidney transplant period
Bita Geramizadeh, Negar Azarpira, Maryam Ayatollahi, Ghanbar-Ali Rais-Jalali, Mahdokht Aghdai, Ramin Yaghoobi, Mehrzad Banihashemi, Zahra Malekpour, Seyed Ali Malek-Hosseini
Transplant Research Center, Pathology Department, Shiraz University of Medical Sciences, Shiraz, Iran
Pathology Department,Transplant Research Center, Shiraz University of Medical Sciences, P.O. Box 71345-1864, Shiraz
Management of renal transplant patients requires periodic measurement of renal function especially in early post transplant period. This is usually assessed by measuring the creatinine clearance, but because of its limitations, it is not an ideal marker for assessing the renal function. Serum Cystatin C (sCyC) appears to be an endogenous marker of glomerular filtration rate (GFR). To assess the use of sCyC as a marker of renal function in kidney transplant patients, we compared it with serum creatinine (sCr) and 24-hour urine creatinine clearance (CrCl) in the first week post-transplantation. Among 60 patients (62.8% men, 37.2% women) undergoing kidney transplantation (average age: 44.87 ± 13.37 years), we determined renal function at 1, 3, 5, and 7 days after kidney transplantation using: sCr, sCyC and CrCl in a 24-hours urine specimen. During the first 5 days following transplantation, there was a progressive decline in sCr levels. In the first 5 days, post transplantation we could not find good correlation between CrC and sCyC, and the sCyC increased during these 5 days, but after that in day 7, there was a good correlation between CrC and sCyC which is coinciding with decreasing the dose of steroid (r= .625). Therefore, we recommend using sCyC may be used as a marker of renal function after one-week post kidney transplantation.
|How to cite this article:|
Geramizadeh B, Azarpira N, Ayatollahi M, Rais-Jalali GA, Aghdai M, Yaghoobi R, Banihashemi M, Malekpour Z, Malek-Hosseini SA. Value of serum cystatin C as a marker of renal function in the early post kidney transplant period.Saudi J Kidney Dis Transpl 2009;20:1015-1017
|How to cite this URL:|
Geramizadeh B, Azarpira N, Ayatollahi M, Rais-Jalali GA, Aghdai M, Yaghoobi R, Banihashemi M, Malekpour Z, Malek-Hosseini SA. Value of serum cystatin C as a marker of renal function in the early post kidney transplant period. Saudi J Kidney Dis Transpl [serial online] 2009 [cited 2022 Sep 29 ];20:1015-1017
Available from: https://www.sjkdt.org/text.asp?2009/20/6/1015/57256
Accurate and rapid assessment of renal function is crucial in renal transplant recipients especially in the early post transplantation period.  The ideal marker for GFR is an endogenous substance with a regular production rate and constant level in the circulation. It should be freely filtered by glomeruli, appear exclusively in the urine and should not bind proteins. It also should not suffer alteration by drugs. Serum creatinine (sCr) is the time tested parameter for renal function.  GFR is under or over estimated by creatinine clearance, because of its tubular secretion, and variations with muscle mass, diet, and drugs. For years, attempts have been made with many substances, one of which is sCyC. Serum Cystatin C (sCyC) has recently been proposed as an alternative marker for estimation of GFR. 
The goal of this study was to assess the value of sCyC as a marker of renal function in the early post kidney transplant period and compare with sCr and creatinine clearance in 24 hour urine.
Patients and Methods
Sixty consecutive randomly selected renal transplant recipients were prospectively included in this study (62.8% men, 37.2% women, and average age 44.87 ± 13.37 years). sCyC, sCr and urine Cr (UCr) were measured at 1, 3, 5 and 7 days post transplant. sCr was measured by Jaffe colorimetric method and sCyC by ELISA method.
Estimation of creatinine clearance (CrCl) was performed according to the 24 hours urine specimen collection. Estimates of GFR were obtained using CrCl:
Cr Cl = Urine Cr Χ Urine volume/sCr Χ minutes All clearances were expressed as mL/min/1.73 m 2 .
For statistical analysis, data were analyzed using version 15 of the SPSS statistical program. A Pearson correlation coefficient was employed to correlate sCyC with sCr and creatinine clearance. Values of P 
Cystatin C is a low molecular weight basic protein (13.26 KD), which is synthesized by all nucleated cells at a constant rate.  Because of its low molecular weight and positive charge, Cystatin C is freely filtered by the glomeruli. It is not secreted but reabsorbed by tubular epithelial cells and subsequently catabolized, so that it does not return to the blood.  Many studies have indicated that sCyC may be superior to sCr as a GFR marker for patients suffering from renal diseases especially those with early and moderate reduction of GFR. 
Our study showed that sCyC is well correlated with CrC after 5 days of post transplantation period. During the first 5 days post transplantation sCyC is affected by the steroid dose; higher dose resulted in higher levels of sCyC when serum creatinine was decreasing. Our results are similar to the report by Xu et al  and Mendiluce et al  ; who showed that sCyC is a useful determinant of GFR in the renal transplant patients with moderate impairment of renal function and higher steroid dose results in higher sCyC levels respectively.
In conclusion our study suggests that during the first week, after transplantation, sCr is still a good marker to assess the renal function. The level of sCyC is dependent on high steroid dose in the first week post renal transplantation and should be used as a marker of renal function afterwards.
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