CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 6, July 2012
e6
AFRICA
calcification is controlled by factors other than circulating
calcium and phosphate levels.
In a previous study, we found that the expression of p53 was
inhibited inVSMCs from patients on maintenance haemodialysis,
while vascular calcification was widely present.
13
In line with
these findings, Ohmi
et al
.
24
found that VSMCs from p53
knock-out mice aortas revealed an extended bipolar shape and
expressed h-caldesmon and calponin, as well as a smooth muscle
actin as protein markers of differentiated smooth muscle. This
Correlation coefficients (
R
) and
p
-values are shown in Table
2. The levels of expression of BMP-2, RUNX2, Osx and ALP
were significantly negatively correlated with those of p53 and
α
-SMA. Correlation coefficients and
p
-values are shown in
Tables 3 and 4.
Discussion
Although circulating calcium and phosphate concentrations have
been correlated with the progression of vascular calcification
in longitudinal studies of dialysis patients,
22,23
they only partly
account for the calcification. It is clear then that vascular
TABLE 3. LINEAR CORRELATION BETWEEN P53 PROTEIN
AND OTHER CALCIFICATION-RELATED PROTEINS IN
VSMCS FROM P53+/+ MICEAFTER 5/6 NEPHRECTOMY
Protein
R
p
-value
BMP-2
–0.671
<
0.001
RUNX2
–0.586
<
0.001
Osx
–0.622
<
0.001
ALP
–0.703
<
0.001
TABLE 4. LINEAR CORRELATION BETWEEN
a
-SMA
AND OTHER CALCIFICATION-RELATED PROTEINS
INVSMCSAFTER 5/6 NEPHRECTOMY
P53(+/+) mice
p53(–/–) mice
Protein
R
p
-value
R
p
-value
p53
0.664
< 0.001
BMP-2
–0.585
< 0.001
–0.629
< 0.001
RUNX2
–0.502
< 0.001
–0.610
< 0.001
Osx
–0.569
< 0.001
–0.716
< 0.001
ALP
–0.742
< 0.001
–0.758
< 0.001
Fig. 4. Immunohistochemistry analysis for p53, ALP and
α
-SMA in the aorta at 12 weeks after 5/6 Nx or 5/6 Nx
+
HP
(original magnification,
×
200). In p53–/– mice with 5/6 Nx
+
HP, ALP expression was high, but
α
-SMA was low, and no
p53 was detected, while related heavy mineral deposition was also detected. On the other hand, a weak positive stain-
ing of ALP, and enhanced positive staining of p53 and
α
-SMA was detected in p53
+
/
+
mice, while moderate mineral
deposition could be detected. A brown colour indicated the presence of proteins and a black colour indicated mineral
deposition.
p53
+
/
+
mice
p53–/– mice
p53
ALP
a
-SMA
Nx
Nx
+
HP
Nx
Nx
+
HP
A
B
C
D
E
F
G
H
I
J
K
L
