Experimental model:

•Daily intra-peritoneal instillation of PD solution (Dianeal 3.86%) for 4-5 weeks via mini vascular access port (fig 1)

•Daily administration of COX-2 inhibitor (Celecoxib) (20mg/kg of body weight) diluted with PEG 95% via oral gavage

•On sacrifice day 90 min PET test with 30 ml Dianeal

METHODS

INTRODUCTION• Peritoneal dialysis (PD) is associated with an inflammatory response of the peritoneal membrane, with new vessel formation,

fibrosis, and loss of ultrafiltration capacity • Cyclooxygenase-2(COX-2) is an inducible enzyme expressed in several tissues under pro-inflammatory stimuli. It regulates the

production of prostaglandin involved in inflammation and angiogenesis process

• AIM of the study: investigated COX-2 inhibition effect on peritoneal morphological and functional changes induced by PD Fluid .

COX-2 Inhibition Largely Prevents Peritoneal Worsening in Rat PD Model

P Fabbrini1, M Zareie1, PM ter Wee2, ED Keuning1, RHJ Beelen1, J van den Born1

1 Dept. Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, Netherlands, 2 Dept. Nephrology,VU University medical Center, Amsterdam, Netherlands

PEG 95% + CELECOXIB

PEG 95% + CELECOXIB

PEG 95%

PEG 95%

Oral treatment

DIANEAL 3.86%

DIANEAL 3.86%

NO

NO

Pdinstillation

8+GROUP D+I

8+GROUP D

8-GROUP C+I

8-GROUP C

nCatheter

-50

0

50

100

150

200

250

300

350

400

450

500

C C+I D D+I

0

20

40

60

80

100

120

140

160

C C+I D D+I

OMENTUM: ANGIOGENESIS

-total number of blood vessel reduced to 50 % in group D+I vs D (p>0.01 )

-mast cell number reduced to 50 % in group D+I vs D (p>0.01 )

-5

0

5

10

15

20

25

30

35

40

45

50

C C+I D D+I

PARIETAL PERITONEUM: ANGIOGENESIS AND FIBROSIS

- ANGIOGENESIS reduced to 40% in group D+I vs group D (p<0.05) Fig 3

6

8

10

12

14

16

18

20

22

24

26

28

C C+I D D+I

Fig 3: parietal peritoneum stained with CD31ab, red spots (arrows )indicate blood vessels

- FIBROSIS reduced to 40% in group D+I vs group D (p<0.05)

3

4

5

6

7

8

9

10

11

12

13

C C+I D D+I

PET TEST: CELL PARAMETERS

- Total number of cells do not significantly differ between D and D+I

- No significant differences in cell subpopulation between D and D+I

GROUPS

BL

OO

D V

ES

SE

LS

/cm

EC

M t

hic

kn

ess

m

GROUPS

a a

a : p<0.05 vs D

GROUPS

BL

OO

D V

ES

SE

L/c

m 2

MA

ST

CE

LL

S /c

m 2

- No differences between UF capacity of D+I and C/C+I groups.

GROUPS

GROUP C GROUP C+I GROUP D GROUP D+I

Fig 2: Omentum stained with toloudine blue; arrows indicate some blood vessels

GROUP C GROUP C+I GROUP D GROUP D+I

Total cell number 24.1 (13.1-26.9) 19.1 (13.0-23.0) 62.4 (26.2-182.5)a 47.4 (21.4-114.1)a

Macrophages 80.0 (65.0-88.5) 73.0 (57.0-78.0)b 76.0 (55.0-82.5) 69.5 (59.0-79.0)b

Lymphocytes 2.7 (0.0-5.0) 3.0 (0.0-4.0) 12.5 (7.0-25.0)a 16.5 (16.0-34.0)a

Neutrophils 0.0 (0.0-0.0) 0.0 (0.0-0.0) 6.0 (3.0-10.5)a 5.0 (2.0-15.0)a

Eosinophils 7.8 (5.5-14.0) 10.0 (7.0-19.0) 6.5 (1.0-18.0) 2.5 (0.0-15.0) a

Mastcells 9.5 (0.5-10) 15.0 (8.0-27.0) 0.0 (0.0-1.5)a 0.0 (0.0-1.0)a

PET TEST: FUNCTIONAL PARAMETERS

CONCLUSION•Cox-2 downstream products have a major role in the peritoneal angiogenesis and fibrosis after exposure to PDF. Its suppression produced a generalized reduction of peritoneal damage in PDF exposed rats especially regarding omentum and parietal peritoneum

•Cox-2 suppression completely prevent the lost of peritoneal UF capacity observed in the PDF exposed control group

RESULTS

FIG 1 : a mini vascular acces port and a rat few days after implantation surgery

Experimental groups:

GROUP C GROUP C+I

GROUP D GROUP D+I

UL

TR

AF

ILT

AT

ION

VO

LU

ME

ml

a : p<0.05 vs C and C+I b : p <0.05 vs C

a

a : p<0.01 vs C ; C+I and D+I

MESOTHELIAL CELLS ON LIVER:

213 (169-251) 199 (135-211) 1025 (56-121)* 1055 (91-153)*

C C+I D D+I

* P<0.01 vs C and C+I

-No differences in mesothelium regenerative response between group D and D+I