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PubMed2003

Hyper-vascular change and formation of advanced glycation endproducts in the peritoneum caused by methylglyoxal and the effect of an anti-oxidant, sodium sulfite.

OBJECTIVE: Methylglyoxal (MGO) in a heat-sterilized conventional PD solution may damage peritoneal cells directly and/or indirectly by producing advanced glycation endproducts (AGEs). This study was conducted to (a) examine the acute effect of MGO on the peritoneum (including AGE formation) and (b) study the possible AGE suppressive effect of an anti-oxidant, sodium sulfite. METHOD: (1) Human serum albumin (HAS) was continuously incubated with MGO (50 mM) at 37 degrees C for as long as 14 days and the fluorescence intensity (FI) was determined (em. 440, ex. 370). (2) Three types of test solutions - (i) saline; (ii) MGO (20 mM), and (iii) MGO with sodium sulfite (30 mM) - were administered intraperitoneally to 8-week-old rats once a day for 5 consecutive days. The parietal peritoneum was examined macroscopically on the 6th day for immunostaining of anti-AGE antibodies. RESULT: (1) An increase in FI of HSA was observed as a function of the incubation period in the MGO solution. (2) Prominent hypervascularity and intense immunostaining of anti-AGE Ab were noted in MGO-treated rats, whereas the macroscopic alterations were suppressed in the rats that had been treated with sodium sulfite. CONCLUSION: MGO-induced hypervascularity and AGE formation in the peritoneum, as well as macroscopic alterations were suppressed by sodium sulfite. This may indicate that there is a risk of MGO causing a peritoneal injury and that the therapeutic potential of an anti-oxidant for this type of injury may exist.

Animals↗
PubMed1980

Fibrinolytic activity of the human peritoneum.

A new method is presented to measure the content of plasminogen activator in single layers of mesothelial cells to investigate the fibrinolytic activity of the human peritoneum. The results demonstrate the synthesis of plasminogen activators in different areas of the peritoneal serosa. In the omental peritoneum, the fibrinolytic activity is significantly higher than in other parts of the peritoneum.

Adolescent↗
PubMed1989

Morphology of the peritoneum in CAPD.

Stimulated by the development of continuous ambulatory peritoneal dialysis (CAPD), it was only in the last decade that normal and dialysate-exposed peritoneum were examined by electron microscopy. Biopsies of parietal peritoneum from patients on CAPD show ultrastructural alterations in the mesothelium consisting of an increased development of the rough endoplasmic reticulum but a decrease in surface microvilli and micropinocytotic vesicles as compared to tissue from normal controls or uremic individuals. Alterations in amount and consistency of submesothelial ground substance, and number and disposition of collagen fibers combined with mesothelial changes together constitute the 'reactive' peritoneum of peritoneal dialysis.

Fibrosis↗
PubMed1985

Fenestrated capillaries in human parietal and rabbit diaphragmatic peritoneum.

Samples of parietal peritoneum from 20 patients (11 of them chronic uremics) and biopsies of diaphragmatic peritoneum from 5 apparently normal female New Zealand rabbits were examined by electron microscopy. One out of 20 patients and 3 out of 5 rabbits showed fenestrated capillaries. This report is the first published demonstration of the existence of fenestrated capillaries in human parietal and rabbit diaphragmatic peritoneum. They represented a small fraction of the peritoneal microvascular bed which was mainly formed by capillaries of the continuous type. Fenestrae of the observed fenestrated capillaries showed diaphragms. Results of this study indicate that different peritoneal microvascular segments can show different microvascular ultrastructures and possibly have a different physiology and different mechanisms of transperitoneal transfer of water and solutes.

Animals↗
PubMed1988

Ruthenium-red-stained anionic charges of rat and mice mesothelial cells and basal lamina: the peritoneum is a negatively charged dialyzing membrane.

The peritoneum has been classically considered to be an inert passive membrane. Previous studies demonstrated the presence of fixed anionic charges at the level of the peritoneal microvasculature and the subserosal interstitium. The present study describes the selective distribution of fixed anionic charges in the mesothelial cell plasmalemma and organelles as well as in the submesothelial basal lamina of rat and mice visceral, parietal and diaphragmatic peritoneum. These data support the idea that the peritoneum should be considered a negatively charged biological dialyzing membrane with selective capabilities. Therefore, transperitoneal transfer of charged solutes cannot be analyzed just on the basis of their molecular weight, size and shape.

Animals↗
PubMed1996

Effect of culture supernatants of endometriotic lesions, uterine endometrium and peritoneum from rats with experimental endometriosis on the natural killer activity of spleen cells.

Experimental endometriosis in rats was induced by autotransplanting the uterine endometrium to the peritoneum. In all rats, endometrial implants developed into endometriotic tissues similar to those in humans about 2 weeks after transplantation. Natural killer (NK) activity of spleen cells in the endometriosis model rats was significantly (p < 0.05) lower than that in the sham-operated intact rats. The inhibited NK activity in the endometriosis rats recovered to the level in intact rats with danazol (but not buserelin). The supernatant after 24-hour culture of endometrial tissues from both intact and model rats seemed to have significant inhibitory effects on NK activity. The supernatant from endometrial grafts showed significantly (p < 0.05) higher inhibitory effects than that from the endometrial tissues. The inhibitory effects were significantly (p < 0.05) reduced by treatment with danazol or buserelin to the untreated level. In addition, supernatants of unaffected peritoneal tissues from the endometriosis rats had significantly (p < 0.01) higher inhibitory effects on NK activity than those from the intact rats. Even when uterine serosa or silicone was implanted to the peritoneum, the supernatants of the contralateral peritoneal tissues showed significantly (p < 0.05) higher inhibitory effects than those from the intact rats, while having significantly (p < 0.05) lower inhibitory effects than those from the endometriosis rats. These results suggest that this marked inhibitory effect on NK activity by the peritoneum may be associated with the development and progression of endometriosis.

Animals↗
PubMed2002

Diffusive permeability of rabbit peritoneum for small solutes in vitro: effect of gentamicin and insulin.

The purpose of the in vitro study was to compare the diffusive transport of creatinine, uric acid and glucose, directed from the interstitial (I) to the mesothelial (M) side of the peritoneum and in the opposite direction, before (15-60min) and after (75-120min) application of gentamicin and insulin. The experiments were undertaken on the rabbit parietal peritoneum in a modified Ussing chamber. A mathematical model was used to calculate a diffusive permeability coefficient P (in cm/s) and a diffusive mass transport coefficient KH (in mL/min). In the basic experimental series without drugs, the dynamics of peritoneal transport for examined solutes remained constant and there were no differences between transport directions (I--> M and M--> I). Mean values of P+/-SEM (KH+/-SEM) were 3.06+/-0.32 (321.1+/-33.5), 2.09+/-0.29 (219.2+/-30.7) and 2.73+/-0.47 (286.7+/-49.6) for creatinine, uric acid and glucose, respectively. The introduction of gentamicin decreased glucose transport directed from the mesothelial to the interstitial side of the membrane by about 12%. After insulin application we observed the increase of creatinine and glucose peritoneal transport rate. For creatinine, the above augmentation was by about 31% for I--> M and 83% for M--> I direction. In these conditions, the glucose transport directed from the interstitial to the mesothelial side of membrane increased by about 24%. Generally, in vitro gentamicin decreases, but insulin increases the diffusive permeability of the peritoneum for some small solutes. We suppose that these findings may be important for the efficiency of peritoneal dialysis.

Animals↗
PubMed2001

Chronic uremia induces permeability changes, increased nitric oxide synthase expression, and structural modifications in the peritoneum.

Advanced glycation end products (AGE), growth factors, and nitric oxide contribute to alterations of the peritoneum during peritoneal dialysis (PD). These mediators are also involved in chronic uremia, a condition associated with increased permeability of serosal membranes. It is unknown whether chronic uremia per se modifies the peritoneum before PD initiation. A rat model of subtotal nephrectomy was used to measure peritoneal permeability after 3, 6, and 9 wk, in parallel with peritoneal nitric oxide synthase (NOS) isoform expression and activity and structural changes. Uremic rats were characterized by a higher peritoneal permeability for small solutes and an increased NOS activity due to the up-regulation of endothelial and neuronal NOS. The permeability changes and increased NOS activities correlated with the degree of renal failure. Focal areas of vascular proliferation and fibrosis were detected in uremic rats, in relation with a transient up-regulation of vascular endothelial growth factor and basic fibroblast growth factor, as well as vascular deposits of the AGE carboxymethyllysine and pentosidine. Correction of anemia with erythropoietin did not prevent the permeability or structural changes in uremic rats. Thus, in this rat model, uremia induces permeability and structural changes in the peritoneum, in parallel with AGE deposits and up-regulation of specific NOS isoforms and growth factors. These data suggest an independent contribution of uremia in the peritoneal changes during PD and offer a paradigm to better understand the modifications of serosal membranes in uremia.

Anemia↗
PubMed2005

Frozen section of the gastrointestinal tract, appendix, and peritoneum.

CONTEXT: Intraoperative consultation is frequently requested by surgeons operating on the gastrointestinal tract, appendix, and peritoneum. In this setting, the pathologist's diagnosis plays a central role in determining whether a resection is needed, and if so, how much to resect and whether it was adequate. There is no room for errors in the frozen section laboratory, because a small mistake can have serious consequences. To my knowledge, no recent books or publications in the literature have dealt with this important topic. OBJECTIVE: To review the intraoperative consultation of the gastrointestinal tract, appendix, and peritoneum. DATA SOURCES: The MEDLINE database was queried for keywords, including gastrointestinal, esophagus, stomach, esophageal, gastric, small intestine, and all other names of the gastrointestinal tract, peritoneum, and appendix in combination with frozen section. All suitable articles were retrieved and reviewed. This literature search and my personal experience formed the basis of this review. CONCLUSIONS: The role, value, and limitations of frozen section and gross consultation are different for different areas of the gastrointestinal tract, even for the same types of lesions. Close interaction with the surgeon and knowing what is intended from the frozen section, what will be done following a certain diagnosis, and what is the minimal information needed from the pathologist at the time of frozen section are essential for proper patient management.

Appendicitis↗
PubMedDate not supplied

Structural and functional alterations of the peritoneum after prolonged exposure to dialysis solutions: role of aminoguanidine.

OBJECTIVE: The effect of long-term use of high glucose dialysate on peritoneal structure and function, and its relation with accumulation of advanced glycosylation end-product (AGE) in the peritoneum was investigated in this study. METHODS: Dialysates with 4.25% glucose were injected into the peritoneal cavity of normal rats for 12 weeks without (PD, n = 7) and with (1 g/L, PD+AG, n = 7) aminoguanidine in their drinking water. Rats not having intraperitoneal (IP) injection served as control (n = 9). After 12 weeks of IP injection, a 2-hour peritoneal equilibration test (PET) was performed using 30 mL 4.25% glucose dialysate. Intraperitoneal volume (IPV), dialysate-to-plasma urea ratio at 2 hours (D/P2), the ratio of dialysate glucose at 2 hours to initial dialysate glucose (D2/D0), and the peritoneal fluid absorption rate (Qa) were evaluated. After the PET, samples of the parietal peritoneum were taken for hematoxylin and eosin (H&E) staining and immunohistochemical staining for AGE. RESULTS: The IPV and D2/D0 glucose were significantly lower and Qa and D2/P2 urea significantly higher in the PD group than in the control group. Aminoguanidine reversed in part the changes in IPV and D2/P2 urea in the PD group; it had no effect on Qa and D2/D0 glucose. The H&E staining showed a linear mesothelial lining with negligible cells and capillaries in the narrow submesothelial space in the control group. Mesothelial denudation and submesothelial infiltration of monocytes and capillary formation were observed in the PD group. Mesothelial denudation was relatively intact in the PD+AG group compared with the PD group. Submesothelial monocyte infiltration and capillary formation in the PD+AG group were not as prominent as in the PD group. Positive AGE staining was found in the submesothelial space, vascular walls, and endomysium in the PD group, while it was markedly attenuated in PD+AG group and negligible in the control group. CONCLUSION: Long-term use of high glucose solutions induced peritoneal AGE accumulation and mesothelial denudation, and increased peritoneal permeability and peritoneal fluid absorption rate. Inhibition of peritoneal AGE accumulation prevented those functional and structural damages to the peritoneum.

Animals↗
PubMed1998

[Effect of Shenmai injection on morphological structure of kidney and peritoneum in rats with 5/6 nephrectomy].

OBJECTIVE: To study the protective effect of Shenmai injection (SMI) on kidney and peritoneum in rats with 5/6 nephrectomy. METHODS: By using cell morphological quantification, light microscopy and scanning electron microscopy, the morphological structure changes of peritoneum and kidney in rats with 5/6 nephrectomy caused chronic renal failure model after the intramuscular or intraperitoneal injection of SMI were observed. RESULTS: The SMI injection could relieve glomerular sclerosis, promote the recovery and proliferation of injured peritoneal mesothelial cell. The effect of the SMI intraperitoneal injection is better than that intramuscular of injection. CONCLUSION: The SMI has the protective effect on kidney and peritoneum in rats with 5/6 nephrectomy.

Animals↗
PubMed2001

Renin-angiotensin system plays an important role in the regulation of water transport in the peritoneum.

The present study was carried out to investigate changes in the expression of aquaporins (AQPs) in the peritoneum. The effects of the renin-angiotensin system on the expression of AQPs with and without angiotensin converting enzyme inhibitor (ACEI) or angiotensin II type 1a receptor blocker (ARB) were then examined. We divided 20 male Wistar Kyoto (WKY) rats into four groups, dialyzed with these solutions: saline; 10% glucose (TZ); 10% glucose plus benazepril (ACEI: 4 mg/kg daily); and 10% glucose plus valsartan (ARB: 10 mg/kg daily). The ACEI and ARB were administered into the peritoneum for 7 days. Expression of AQP-1-AQP-4 mRNA was studied by semiquantitative reverse-transcription polymerase chain reaction (RT-PCR). Ultrafiltration volume (UFV) and peritoneal function were measured by peritoneal equilibration test (PET). In the TZ group, expression of AQP-1 and AQP-4 was enhanced in parallel with an increment in UFV. Expression of AQP-1 and AQP-4 was also observed in the mesothelium by immunofluorescence microscopy. On the other hand, in ACEI- and ARB-treated rats, expression of AQP-1 and AQP-4 was significantly suppressed, accompanied by loss of UFV. Our results suggest that the renin-angiotensin system plays an important role in the regulation of water transport in the peritoneum. Administration of ACEI or ARB in patients undergoing continuous ambulatory peritoneal dialysis should be carried out with caution.

Angiotensin II↗
PubMed2001

Aspirin protected the nitric oxide/cyclic GMP generating system in human peritoneum.

OBJECTIVE: Changes in the expression of endothelial nitric oxide synthase (eNOS) in the peritoneum could be involved in the peritoneal dysfunction associated with peritoneal inflammation. The aim of the present study was to analyze the effect of Escherichia coli lipopolysaccharide (LPS) on eNOS expression in samples of human peritoneum. The effect of aspirin, a drug with anti-inflammatory properties, was also determined. RESULTS: The eNOS protein expressed in human peritoneal tissue was reduced by LPS (10 microg/mL) in a time-dependent manner. The eNOS was expressed mainly in capillary endothelial cells and mesothelial cells. Anti-inflammatory doses of aspirin (1-10 mmol/L) restored eNOS expression in LPS-stimulated human peritoneal tissue samples. The main intracellular receptor of NO, soluble guanylate cyclase (sGC), was also downregulated by LPS. This effect was prevented by aspirin (5 mmol/L). CONCLUSION: Protein expression of the eNOS-sGC system in the peritoneal tissue was downregulated by LPS. High doses of aspirin protected both eNOS protein expression and sGC in human peritoneum. These findings suggest a new mechanism of action of aspirin that could be involved in the prevention of peritoneal dysfunction during inflammation.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

[Effect of pneumoperitoneum on ultrastructure of parietal peritoneum in experimentally induced peritonitis in the rat].

Aim of this study was to analyse the effect of gastric perforation induced peritonitis and a pneumoperitoneum (PP) on the ultrastructure of the parietal peritoneum. After randomisation rats allocated to groups I and II were subjected to standardized gastrotomy simulating gastric perforation. After a 12-h-interval a PP was induced in groups I and III. After PP for 60 min a primary fixant was injected intraperitoneally as the abdominal wall was still extended, as well as 30 s, 2 h and 12 h after release of the PP. In groups II and IV simple puncture of the abdomen was performed. Animals were sacrified and tissue specimens taken from the parietal peritoneum of the left diaphragm were analysed using raster electronic miroscopy (REM: 100x to 5000x). In group II (gastric perforation without PP) microvilli appeared shrunk and coarse, while integrity of the mesothelial cell layer remained intact up to 2 h after abdominal puncture. In group I (gastric perforation with PP) distortion of the mesothelial cell layer with concomittant opening of stomata to the submesothelial tissue was observed already in specimens harvested as the abdominal wall was still extended. Concomittantly scarce microvilli appearing coarse and thickened were laid flat on top of the mesothelial cells. After desufflation a rapid process of mesothelial desintegration with disruption from the submesothelial layer and vanishing of microvilli occurred. In REM analysis of parietal peritoneum premature distortion and desintegration of the mesothelial cell layer was observed after exposure to increased abdominal pressure and to gastric perforation-induced peritonitis.

Animals↗
PubMed2003

Characterization of long-term survival of syngeneic hepatocytes in rat peritoneum.

Hepatocyte transplantation is a potential therapy for both acute and chronic hepatic insufficiency and also for treatment of inborn errors of metabolism affecting the liver. The peritoneum is one site for implantation and has several advantages: cells implanted there can be easily identified and observed, and it has a relatively large capacity. Long-term survival using "pure" hepatocytes in the peritoneum have been disappointing. We hypothesized that cotransplantation of hepatocytes with nonparenchymal cells would help maintain differentiated hepatocyte function. Rat liver cells transplanted intraperitoneally into August rats were sacrificed at 7 days, 1, 3, 6, 9, and 12 months and analyzed for presence, basal proliferation, and functionality of hepatocytes. To demonstrate that ectopic hepatocytes remained susceptible to exogenous growth factors affecting cell proliferation, rats 9 and 12 months after transplantation were stimulated with tri-iodothyronine and KGF. Hepatocytes were identified 7 days to >12 months, by H&E and immunohistochemically, as ectopic islands in the omental fat. Functionality was confirmed by glycogen deposition. Basal proliferation in 7-day rats was 28.0 +/- 10/1000 hepatocytes in ectopic islands (cf. 5.70 +/- 2.7/1000 in recipient liver). Proliferation in ectopic islands was greater than host liver. Growth factor-stimulated proliferation in ectopic islands induced a 70-fold increase in DNA synthesis. In conclusion, hepatocytes transplanted with nonparenchymal cells survive, proliferate, and function in the peritoneum of normal rats, and respond to exogenous growth stimuli. Their survival and proliferation in the presence of a normal functioning liver has implications for the potential use of the peritoneal site clinically for supplementation of liver function in metabolic disorders.

Animals↗
PubMedDate not supplied

Better preservation of the peritoneum in rats exposed to amino acid-based peritoneal dialysis fluid.

BACKGROUND: Glucose-containing peritoneal dialysis fluids (PDF) show impaired biocompatibility, which is related partly to their high glucose content, presence of glucose degradation products, low pH, and lactate buffer, or a combination of these factors. In a rat chronic peritoneal exposure model, we compared effects of an amino acid-based PDF (AA-PDF) with a glucose-containing PDF on the peritoneal microcirculation and morphology. METHOD: Two groups of rats received 10 mL of either fluid daily for 5 weeks via peritoneal catheters connected to implanted subcutaneous mini vascular access ports. Leukocyte-endothelium interactions in the mesenteric venules were investigated by intravital microscopy. Quantification of angiogenesis and fibrosis and inspection of the mesothelial cell layer were performed by light and electron microscopy. RESULTS: Daily exposure to glucose-containing PDF resulted in a significant increase in the number of rolling leukocytes in mesenteric venules, whereas instillation of AA-PDF did not change the level of leukocyte rolling. Glucose-containing PDF evoked a significantly higher number of milky spots in the omentum, whereas this response was significantly reduced in animals exposed to the AA-PDF (p < 0.02). Chronic instillation of glucose-containing PDF induced angiogenesis in various peritoneal tissues, accompanied by fibrosis in the mesentery and parietal peritoneum. Quantitative morphometric evaluation of omentum and mesentery showed a clear trend toward less angiogenesis after treatment with the AA-PDF compared to the glucose-containing PDF, which reached statistical significance in the parietal peritoneum (p < 0.04). Instillation of AA-PDF resulted in approximately 50% reduction of fibrosis in the mesentery (p < 0.04) and approximately 25% reduction in the parietal peritoneum (p < 0.009) compared to glucose-containing PDF. Glucose-containing PDF damaged the mesothelial cell layer, whereas the mesotheium was intact after AA-PDF treatment, as evidenced by electron microscopy. CONCLUSION: Our data in a rat chronic peritoneal exposure model clearly demonstrate reduced immune activation (evidenced by decreased number of rolling leukocytes and decreased induction of omental milky spots) and reduced neoangiogenesis, fibrosis, and mesothelial damage of the peritoneal membrane after treatment with AA-PDF compared to glucose-containing PDF.

Amino Acids↗
PubMed2005

Is normal saline harmful to the peritoneum?

BACKGROUND: Normal saline (0.9% NaCl) is used during various abdominal surgical interventions and during peritoneal dialysis to rinse the peritoneal cavity. Although no clear clinical evidence exists for the bioincompatibility of normal saline, various experimental studies have suggested that 0.9% NaCl solution can initiate fibrosis of peritoneum. MATERIAL AND METHODS: We review the data derived from in vitro and in vivo experimental studies demonstrating the cytotoxic effect of 0.9% NaCl and its ability to initiate peritoneal adhesions. RESULTS: Normal saline reduces the viability and fibrinolytic activity of peritoneal mesothelial cells. Use of normal saline to wash the peritoneal cavity during abdominal operations or after chronic peritoneal dialysis is more likely to produce adhesions than is no irrigation at all. Chronic exposure of the peritoneum to normal saline causes overgrowth of the connective tissue and formation of new blood vessels within that tissue. CONCLUSION: Normal saline is a bioincompatible solution that predisposes to the formation of peritoneal adhesions and fibrosis of the peritoneum. A 0.9% NaCl solution should therefore not be used to rinse the peritoneal cavity after interruption of peritoneal dialysis.

Animals↗
PubMed2006

[Effect of carbon dioxide pneumoperitoneum during laparoscopic surgery on morphology of peritoneum].

OBJECTIVE: To investigate the influence of carbon dioxide (CO2) pneumoperitoneum during laparoscopic surgery on morphology of peritoneum. METHODS: Forty patients with myoma of uterus or simple ovarian cyst excluding peritonitis were randomly divided into 2 equal groups to undergo laparoscopic surgery with CO2 pneumoperitoneum or laparotomy respectively. Specimens of parietal peritoneum were obtained at different time points, 0, 30, 90, and 120 min after the beginning of observation, i.e. e, insufflation or opening of the peritoneal cavity, to undergo transmission electron microscopy and scanning electron microscopy to observe the morphological changes of mesothelial cells. RESULTS: In the laparotomy group, up to the time point of 60 min, there was no marked change of mesothelial cells. Intercellular cleft were occasionally found since 90 min and became significant 120 min after. However, in the CO2 pneumoperitoneum group bulging up of mesothelial cells was evident immediately at the time of filling of CO2, intercellular spaces could be found 30 min later, 60 min later intercellular cleft deep to the underlying basement membrane could be seen and the basement membrane lost its continuity and became uncovered, and 120 min later such changes became more significant and a small amount of lymphocytes and macrophages were found in the intercellular clefts. CONCLUSION: Carbon dioxide pneumoperitoneum during laparoscopic surgery causes significant morphological changes in the peritoneum duration of insufflation dependently.

Carbon Dioxide↗