Stone formation is proportional to papillary surface coverage by Randall's plaque.
OBJECTIVE
Randall's plaques are common in calcium oxalate (CaOx) stone formers (SF). Plaque coverage correlates directly with urine calcium excretion and inversely with urine volume. We hypothesize that plaque coverage should increase proportionally with increasing stone number. We measured plaque areas in idiopathic CaOx stone formers and nonstone formers (NSF), and identified significant relationships with quantified stone histories.


METHODS
A total of 13 SFs and 4 control NSFs underwent nephroscopic papillary mapping with representative still images and MPEG (Moving Pictures Experts Group) movies used to identify plaque and papillary borders. Stone histories were obtained through patient interviews, and from medical records and radiographs. The relationship of plaque coverage to clinical stone events was assessed by general multivariate linear modeling. Log transformation normalized the distribution of percent plaque coverage and stone number.


RESULTS
Plaque surface area in SFs differed significantly from that in NSFs (p <0.0001). The duration of stone disease and the log transformed percent plaque coverage correlated significantly with the number of stones (0.677 and 0.620, p = 0.003 and 0.008, respectively). On multivariate analysis and correcting for the duration of stone disease total percent plaque coverage correlated significantly with the number of stones (R = 0.496, p = 0.05). Disease duration and plaque coverage did not correlate significantly (p = 0.257).


CONCLUSIONS
Percent plaque coverage directly correlates with the number of stones formed even when corrected for the duration of stone disease. However, plaque coverage does not correlate with the duration of stone disease. These results support the hypothesis that the pathogenesis of CaOx stones begins with Randall's plaques.
Kim
Samuel C
SC
Methodist Hospital Institute for Kidney Stone Disease, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
Coe
Fredric L
FL
Tinmouth
William W
WW
Kuo
Ramsay L
RL
Paterson
Ryan F
RF
Parks
Joan H
JH
Munch
Larry C
LC
Evan
Andrew P
AP
Lingeman
James E
JE
D001706:Biopsy / Q000379:methods; D002129:Calcium Oxalate / Q000032:analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007669:Kidney Calculi / Q000737:chemistry / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D007679:Kidney Medulla / Q000473:pathology*; D016014:Linear Models; D009392:Nephrectomy; D009403:Nephrostomy, Percutaneous; D013997:Time Factors
D002129:Calcium Oxalate