Limits...
Predicting the outcome of chronic kidney disease by the estimated nephron number: the rationale and design of PRONEP, a prospective, multicenter, observational cohort study.

Imasawa T, Nakazato T, Ikehira H, Fujikawa H, Nakajima R, Ito T, Ando Y, Yoshimura M, Nakayama M, Yahata K, Sasaki O, Yaomura T, Katafuchi R, Yamamura T, Kawaguchi T, Nishimura M, Kitamura H, Kenmochi T, Shimatsu A - BMC Nephrol (2012)

Bottom Line: The hypothesis of this study is that the estimated nephron number can predict the outcome of a CKD patient.The primary parameter for assessment is the composite of total mortality, renal death, cerebro-cardiovascular events, and a 50% reduction in the eGFR.The results from this study should provide powerful new tools for nephrologists in routine clinical practice.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Hospital Organization Chiba-East Hospital, Chiba, Japan. imasawa@cehpnet.com

ABSTRACT

Background: The nephron number is thought to be associated with the outcome of chronic kidney disease (CKD). If the nephron number can be estimated in the clinical setting, it could become a strong tool to predict renal outcome. This study was designed to estimate the nephron number in CKD patients and to establish a method to predict the outcome by using the estimated nephron number.

Methods/design: The hypothesis of this study is that the estimated nephron number can predict the outcome of a CKD patient. This will be a multicenter, prospective (minimum 3 and maximum 5 years follow-up) study. The subjects will comprise CKD patients aged over 14 years who have undergone a kidney biopsy. From January 2011 to March 2013, we will recruit 600 CKD patients from 10 hospitals belonging to the National Hospital Organization of Japan. The primary parameter for assessment is the composite of total mortality, renal death, cerebro-cardiovascular events, and a 50% reduction in the eGFR. The secondary parameter is the rate of eGFR decline per year. The nephron number will be estimated by the glomerular density in biopsy specimens and the renal cortex volume. This study includes one sub-cohort study to establish the equation to calculate the renal cortex volume. Enrollment will be performed at the time of the kidney biopsy, and the data will consist of a medical interview, ultrasound for measurement of the kidney size, blood or urine test, and the pathological findings of the kidney biopsy. Patients will continue to have medical consultations and receive examinations and/or treatment as usual. The data from the patients will be collected once a year after the kidney biopsy until March 2016. All data using this study are easily obtained in routine clinical practice.

Discussion: This study includes the first trials to estimate the renal cortex volume and nephron number in the general clinical setting. Furthermore, this is the first prospective study to examine whether the nephron number predicts the outcome of CKD patients. The results from this study should provide powerful new tools for nephrologists in routine clinical practice.

Trial registration: UMIN-Clinical Trial Registration, UMIN000004784.

Show MeSH

Related in: MedlinePlus

Definition of the length of the cortex in this study. (A) The length of cortex is measured from the outermost glomerulus to the innermost glomerulus. (B) When the medulla is sandwiched between cortices, the total of two lengths between the outermost glomerulus to the innermost glomerulus is considered the length of the cortex in the section.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3376039&req=5

Figure 5: Definition of the length of the cortex in this study. (A) The length of cortex is measured from the outermost glomerulus to the innermost glomerulus. (B) When the medulla is sandwiched between cortices, the total of two lengths between the outermost glomerulus to the innermost glomerulus is considered the length of the cortex in the section.

Mentions: As a general rule, sections stained by PAS or PAM-HE will be used for the measurement of the glomerular number and the length of the cortex (Figure 5). At the time of the measurement, squared grids will be set in an ocular lens, and thereafter, the length of the cortex will be measured. In the formal definition, the cortex and medulla are separated by the arcuate artery of the kidney. However, it is difficult to clearly discriminate between the cortex and medulla because of the frequent lack of the arcuate artery in the specimen. Therefore, we define the length of the cortex in the kidney biopsy specimen as shown in Figure 5. The needle gage number is also recorded, so that we will know the width of the specimen. The gross square area of the cortex in the specimens can be calculated by the total length of the cortex and the width. The total glomerular number and the number of glomeruli with global sclerosis will also be recorded. If the section has only one glomerulus, the section is ignored. If the total glomerular number in all sections obtained is under 8, such cases will be considered insufficient for the analysis. In line with the usual clinical procedure, the pathological diagnosis will be performed and registered.


Predicting the outcome of chronic kidney disease by the estimated nephron number: the rationale and design of PRONEP, a prospective, multicenter, observational cohort study.

Imasawa T, Nakazato T, Ikehira H, Fujikawa H, Nakajima R, Ito T, Ando Y, Yoshimura M, Nakayama M, Yahata K, Sasaki O, Yaomura T, Katafuchi R, Yamamura T, Kawaguchi T, Nishimura M, Kitamura H, Kenmochi T, Shimatsu A - BMC Nephrol (2012)

Definition of the length of the cortex in this study. (A) The length of cortex is measured from the outermost glomerulus to the innermost glomerulus. (B) When the medulla is sandwiched between cortices, the total of two lengths between the outermost glomerulus to the innermost glomerulus is considered the length of the cortex in the section.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376039&req=5

Figure 5: Definition of the length of the cortex in this study. (A) The length of cortex is measured from the outermost glomerulus to the innermost glomerulus. (B) When the medulla is sandwiched between cortices, the total of two lengths between the outermost glomerulus to the innermost glomerulus is considered the length of the cortex in the section.
Mentions: As a general rule, sections stained by PAS or PAM-HE will be used for the measurement of the glomerular number and the length of the cortex (Figure 5). At the time of the measurement, squared grids will be set in an ocular lens, and thereafter, the length of the cortex will be measured. In the formal definition, the cortex and medulla are separated by the arcuate artery of the kidney. However, it is difficult to clearly discriminate between the cortex and medulla because of the frequent lack of the arcuate artery in the specimen. Therefore, we define the length of the cortex in the kidney biopsy specimen as shown in Figure 5. The needle gage number is also recorded, so that we will know the width of the specimen. The gross square area of the cortex in the specimens can be calculated by the total length of the cortex and the width. The total glomerular number and the number of glomeruli with global sclerosis will also be recorded. If the section has only one glomerulus, the section is ignored. If the total glomerular number in all sections obtained is under 8, such cases will be considered insufficient for the analysis. In line with the usual clinical procedure, the pathological diagnosis will be performed and registered.

Bottom Line: The hypothesis of this study is that the estimated nephron number can predict the outcome of a CKD patient.The primary parameter for assessment is the composite of total mortality, renal death, cerebro-cardiovascular events, and a 50% reduction in the eGFR.The results from this study should provide powerful new tools for nephrologists in routine clinical practice.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Hospital Organization Chiba-East Hospital, Chiba, Japan. imasawa@cehpnet.com

ABSTRACT

Background: The nephron number is thought to be associated with the outcome of chronic kidney disease (CKD). If the nephron number can be estimated in the clinical setting, it could become a strong tool to predict renal outcome. This study was designed to estimate the nephron number in CKD patients and to establish a method to predict the outcome by using the estimated nephron number.

Methods/design: The hypothesis of this study is that the estimated nephron number can predict the outcome of a CKD patient. This will be a multicenter, prospective (minimum 3 and maximum 5 years follow-up) study. The subjects will comprise CKD patients aged over 14 years who have undergone a kidney biopsy. From January 2011 to March 2013, we will recruit 600 CKD patients from 10 hospitals belonging to the National Hospital Organization of Japan. The primary parameter for assessment is the composite of total mortality, renal death, cerebro-cardiovascular events, and a 50% reduction in the eGFR. The secondary parameter is the rate of eGFR decline per year. The nephron number will be estimated by the glomerular density in biopsy specimens and the renal cortex volume. This study includes one sub-cohort study to establish the equation to calculate the renal cortex volume. Enrollment will be performed at the time of the kidney biopsy, and the data will consist of a medical interview, ultrasound for measurement of the kidney size, blood or urine test, and the pathological findings of the kidney biopsy. Patients will continue to have medical consultations and receive examinations and/or treatment as usual. The data from the patients will be collected once a year after the kidney biopsy until March 2016. All data using this study are easily obtained in routine clinical practice.

Discussion: This study includes the first trials to estimate the renal cortex volume and nephron number in the general clinical setting. Furthermore, this is the first prospective study to examine whether the nephron number predicts the outcome of CKD patients. The results from this study should provide powerful new tools for nephrologists in routine clinical practice.

Trial registration: UMIN-Clinical Trial Registration, UMIN000004784.

Show MeSH
Related in: MedlinePlus