26
Clinical insight
P R O B E
• V o l . L I I I • N o . 3 • A p r – J u n 2 0 1 4
Hippuric Acid as a Significant Regulator of
Supersaturation in Calcium Oxalate Lithiasis: The
Physiological Evidence
Atanassova SS, Gutzow IS
Biomed Res Int.
2013;2013:1–7.
Introduction
Calcium oxalate stones are the
most common type of stones in
urolithiasis in developed countries. In
addition, it is very important that the
formation of such stones is caused by
some gastrointestinal diseases. Two
main factors characterize a calcium
oxalate (CaOX) calculus as the most
important stone formed in our lives—
on the one hand, this fact is true,
because of its frequency of occurrence
and a high rate of recurrence, but on
the other hand, it is due to the lack
of a significant therapeutic effect
of a dietary or a pharmacological
attack. Despite a number of
promising hypotheses, the pathogenic
mechanism of intrarenal CaOX stone
formation remains, in many aspects,
obscure. We must also say that, based
on the dominant role of hypercalciuria
in the pathogenesis of CaOX stone
formation, the therapeutic efforts
that have been made, prove neither
clinically nor scientifically to be well
applied.
The problem of calculating the
supersaturation in urine (ie, the
driving force of this particular case
A B S T R A C T
At present, the clinical significance
of existing physicochemical and
biological evidence and especially the
results we have obtained from our previous
in vitro experiments have been analyzed, and
we have come to the conclusion that hippuric acid
(C
6
H
5
CONHCH
2
COOH) is a very active solvent
of calcium oxalate (CaOX) in physiological solutions.
Two types of experiments have been discussed—clinical
laboratory analysis on the urine excretion of hippuric
acid (HA) in patients with CaOX lithiasis and detailed
measurements of the kinetics of the dissolution of CaOX
calculi in artificial urine, containing various concentrations
of HA. It turns out that the most probable value of the HA
concentration in the control group is approximately 10 times
higher than the corresponding value in the group of the stone-
formers. Our in vitro analytical measurements demonstrate
even a possibility to dissolve CaOX stones in human urine, in
which increased concentration of HA have been established.
A conclusion can be that drowning out HA is a significant
regulator of CaOX supersaturation and thus a regulation of
CaOX stone formation in human urine. Discussions have
arisen to use increased concentration of HA in urine both as
a solubilizator of CaOX stones in the urinary tract and on
the purpose of a prolonged metaphylactic treatment.
Key Words:
Hippuric acid, calcium oxalate, hyper-
calciuria, biotransformation
