Normal Peritoneum Research Articles

27: Development of a Multiinstitutional Chronic Pelvic Pain Registry

There is a severe lack of multi-institutional collaboration and general research into etiologies for and optimal treatments of chronic pelvic pain. Our objective was to develop a registry of chronic pelvic pain patients to be used by multiinstitutional researchers. The registry is a custom built web-based application that utilizes Adobe Coldfusion version 5 middleware connecting to an Oracle 9i database. Chronic pelvic pain centers and institutions in multiple countries. Chronic pelvic pain patients as defined by ACOG. Data are entered by research staff anywhere they have internet access. Research staff and physicians collect biological specimens which are stored and logged by staff. The registry currently contains 760 serum, plasma, and buffy coat aliquots from 46 subjects. Additional collection of biological specimens will include diseased and normal peritoneum, peritoneal fluid, endometrium, and myometrium. The registry is a HIPAA compliant, secure environment, accessible from any internet connection. User access is determined by the NYU research team. The online version of the registry has been completed and is currently in use at the NYU Medical Center. It is a highly scalable and adaptable online database. Specific protocols can be carried out within this database. The research possibilities within this environment are limitless.

196: Cyclooxygenase-2 Inhibitors Enhances Apoptosis Of Adhesion Fibroblasts

Cycloogenase-2 (COX-2), one of the rate limiting enzymes of prostaglandin (PG) synthesis, may play a role in regulating the development of postsurgical adhesions. We have previously reported the COX-2 and PGE2 levels are significantly higher in adhesions as compared to normal fibroblasts. We have also previously shown that normal peritoneal fibroblasts have a higher apoptosis rate as compared to adhesion fibroblasts. We have also found that hypoxia increases COX-2 and PGE2 levels in normal peritoneal fibroblasts and decrease their rate of apoptosis, which may contribute to the formation of postoperative adhesions. The objective of this project is to determine the effects of COX-2 inhibition on the rate of apoptosis of fibroblasts primary cultures established from normal peritoneum and adhesion tissues of the same patient. Fibroblasts from normal peritoneal and adhesion tissues were cultured under normal condition for 24 hours and treated with 100 microM NS398, a COX-2 inhibitor, for 4 hrs before evaluating apoptosis by the TUNEL assay and flow cytometry. University research laboratory. Women with adhesions undergoing gynecologic surgery. NS398 a COX-2 inhibitor. Baseline apoptosis was less in adhesion fibroblasts (2% apoptotic cells) as compared to normal peritoneal fibroblasts (30% apoptotic cells). NS398 treatment resulted in an increase in the rate of apoptosis in adhesion fibroblasts (27% apoptotic cells) but with not effects on normal fibroblasts (31% apoptotic cells). Our data suggests that adhesion fibroblasts may respond to the inhibition of COX-2 by increasing their rate of apoptosis. Inhibition of COX-2 may be important for the elimination of the adhesion fibroblasts during peritoneal healing.

Differential Expression of Estrogen, Progesterone, Androgen, and Prolactin Receptors in Human Fibroblasts Isolated From Normal Peritoneum and Adhesions

Adhesions are believed to contribute to infertility in 40% of infertile couples and are the most common cause of small bowel obstruction. Also abdominal-pelvic pain is attributed to adhesions in a little less of 30% of cases. Our objective is to characterize fibroblasts isolated from normal peritoneum and adhesion tissues of the same patient in their ability to express hormone receptors.

The Effects of Estradiol on the Expression of Estrogen, Progesterone, Androgen, and Prolactin Receptors in Human Peritoneal Fibroblasts

Previous studies have suggested a possible role of hormonal milieu mediating endometriosis and/or postoperative adhesion development. The objective of this study is to determine the expression of hormone receptors in human fibroblasts from normal peritoneum in response to increasing concentrations of estradiol.

Knockout of Inducible Nitric Oxide Expression Significantly Reduces the Expression of Type I Collagen and Transforming Growth Factor-Beta 1 in Human Peritoneal and Adhesion Fibroblasts

We have previously identified differences between fibroblasts isolated from normal peritoneum and from adhesions, and have identified phenotype differences between these two cell types from the same patients. Specifically, we have shown that adhesion fibroblasts manifest significantly higher levels of type I collagen and TGF-β1, but with lower nitric oxide levels as compared to normal peritoneal fibroblasts. Our objective is to determine the effects of knocking-out the expression of iNOS in human fibroblasts isolated from normal peritoneal and adhesion tissues on the expression levels of type I collagen and TGF-β1.

Cytosolic estrogen and progesterone receptor content in the endometriotic tissues and endometrium in women with and without endometriosis

In order to have a profile of cytosolic estrogen and progesterone receptors in either endometriotic tissue or endometrium in patients with and without endometriosis a cross-sectional study was  performed  involving  43  infertile women. They consisted of 31 (72.09%) endometriosis and 12 (27.91%) non-endometriosis cases; their average age was 32 ±4 years and 32  ±3 years respectively, with the average  length  of  menstrual  cycle  31  ±8  days  and  29  ±1  days  respectively.  The endometriotic tissue was obtained by excision during ope-rative laparoscopy procedure, while the endometrium was obtained  by  biopsy following hysteroscopy  procedure.  These procedures  were  conducted  within  the  periovulatory  period  (on  Day  13-18  of  the  cycle).The  sex  steroid  receptor  content  in  the cytosol  was  measured  quantitatively  using enzyme-immunoassaymethod,  and  calculated  as  sex  steroid  receptor/cytosol  protein (fmol/ml  cytosol).  It  was  found  that  the  average cytosolic estrogen  receptor concentration  in  the  respective  tissues  were 512.99fmol/ml  in  the  endometriotic  ovary compared  with  2369.17  in  normal  ovary and  632.18  fmol/ml  in  the  endometriotic  peritoneum compared  with  9607.61  fmol/ml  in  normal  peritoneum;while 99.28  fmol/ml and 608.33fmol/ml in the endometrium of women with endometriosis and those without endometriosis respectively. The average cytosolic progesterone receptor concentration found in the respective  tissues  were 50.64fmol/ml  in  the  endometriotic  ovary compared  with  6469.42  fmol/ml  in  normal  ovary and1631.40 fmol/ml  in  endometriotic  peritoneum compared with 12466.99 in normal peritoneum, while21.26 fmol/ml and 599.61fmol/ml in the endometrium  of  women  with  endometriosis  and  those  without  endometriosis  respectively.  There  is  no  significant difference in the  receptor concentration  between  each  tissue  according  to  its  topographic  origin. However,  this  result  may  assume  that  the  responsivity  on  hormonal treatment in endometriosis cases willdepend on the cytosolic sex steroid receptor content in the sick tissues, and the peritoneal lesions will possibly give better response than those in other sites. A further clinical trial is necessary. (Med J Indones 2005; 14: 133-41)

Measurement of oxygen and nitric oxide levels in vitro and in vivo: Relationship to postoperative adhesions

This article demonstrates the ability to measure the actual oxygen and nitric oxide levels in cultured fibroblasts established from normal peritoneum and adhesion tissues with and without hypoxia treatment and to measure levels of oxygen and nitric oxide in vivo in various tissues before and after abrasion.

Electron-Microscopic Alterations of the Peritoneum after Both Cold and Heated Carbon Dioxide Pneumoperitoneum

Carbon-dioxide (CO(2)) is used universally as an insufflation agent to create a laparoscopic pneumoperitoneum. In this study, we aimed to examine the electron and light microscopic alterations of the peritoneum after both cold-dry and heated-humidified CO(2) pneumoperitoneum. Thirty male Sprague-Dawley rats were used in this study. The rats were separated into three groups each comprising 10 rats. Group-I: (Control group): Gas insufflation was not applied to these animals. Group-II: These animals received standard cold-dry (21 degrees C, 2% relative humidity) CO(2). Group-III: These animals received heated-humidified (40 degrees C, 98% relative humidity) CO(2). In groups II and III, peritoneal gas was emptied 2 h after pneumoperitoneum application. All rats were killed after 12 h. Peritoneal samples were examined both by scanning electron and light microscopy by two different pathologists who were not aware of the groups. According to light microscopic examination; in group II and III, cellular response (increased lymphocyte) was significantly higher than the control group (P < 0.01). Similarly, in group II cellular response was significantly higher than group III. (P < 0.01). There was no difference in increased capillarity among all groups. (P > 0.05). According to scanning electron microscopic examination, in group I, normal peritoneum was covered by a sheet of flat mesothelial cells densely covered with microvilli. No intercellulary clefts and no free basal lamina were detected. In group II, drastic alterations of the surface layer were seen. The mesothelial cells had extreme desquamation, and the basal membrane was clearly visible. In group III, the mesothelial cells had bulged up to the surface layer and retracted. Intercellulary clefts become visible, but the basal lamina was not seen. Electron and light microscopic examination revealed that heated-humidified CO(2) results in less peritoneal alteration than cold-dry CO(2.) Accordingly, we believe that heated-humidified CO(2) is more suitable for pneumoperitoneum application in laparoscopic surgery especially in selected cases.

Modulation of the expression of vascular endothelial growth factor in human fibroblasts

To examine the up-regulation of vascular endothelial growth factor (VEGF) expression by hypoxia, a crucial event leading to neovascularization, as the reduction in VEGF expression may facilitate minimization of adhesion development. Prospective experimental study. University medical center. Five patients with adhesions undergoing laparotomy with excision of adhesions and normal peritoneum. Adhesion and normal peritoneal fibroblasts were treated with dichloroacetic acid (DCA) or NS-398 (a cyclooxygenase-2 [COX-2] inhibitor) for 24 to 48 hours. A real-time reverse transcriptase polymerase chain reaction (RT-PCR) to quantify relative changes in mRNA levels of VEGF from each treatment. In both normal peritoneal and adhesion fibroblasts, VEGF mRNA was present with statistically significantly higher levels in adhesion fibroblasts (32%). The DCA treatment resulted in a statistically significant decrease in VEGF mRNA levels in adhesion (20%) and normal peritoneal (18%) fibroblasts. The NS-398 treatment resulted in a statistically significant decrease in VEGF mRNA levels in adhesion (25%) and normal peritoneal (16%) fibroblasts. Stimulation of aerobic metabolism by DCA or inhibition of COX-2 by NS-398 reduces VEGF expression. Angiogenesis, which is an integral component in the development of dense vascular adhesions, may be reduced by either COX-2 inhibitors or stimulation of aerobic metabolism by DCA.

Expression pattern and regulation of genes differ between fibroblasts of adhesion and normal human peritoneum

BackgroundInjury to the peritoneum during surgery is followed by a healing process that frequently results in the attachment of adjacent organs by a fibrous mass, referred commonly as adhesions. Because injuries to the peritoneum during surgery are inevitable, it is imperative that we understand the mechanisms of adhesion formation to prevent its occurrence. This requires thorough understanding of the molecular sequence that results in the attachment of injured peritoneum and the development of fibrous tissue. Recent data show that fibroblasts from the injured peritoneum may play a critical role in the formation of adhesion tissues. Therefore, identifying changes in gene expression pattern in the peritoneal fibroblasts during the process may provide clues to the mechanisms by which adhesion develop.MethodsIn this study, we compared expression patterns of larger number of genes in the fibroblasts isolated from adhesion and normal human peritoneum using gene filters. Contributions of TGF-beta1 and hypoxia in the altered expression of specific genes were also examined using a semiquantitative RT-PCR technique.ResultsResults show that several genes are differentially expressed between fibroblasts of normal and adhesion peritoneum and that the peritoneal fibroblast may acquire a different phenotype during adhesion formation. Genes that are differentially expressed between normal and adhesion fibroblasts encode molecules involved in cell adhesion, proliferation, differentiation, migration and factors regulating cytokines, transcription, translation and protein/vesicle trafficking.ConclusionsOur data substantiate that adhesion formation is a multigenic phenomenon and not all changes in gene expression pattern between normal and adhesion fibroblasts are the function of TGF-beta1 and hypoxia that are known to influence adhesion formation. Analysis of the gene expression data in the perspective of known functions of genes connote to additional targets that may be manipulated to inhibit adhesion development.

Acute Peritoneal Dialysis in Rats Results in a Marked Reduction of Interstitial Colloid Osmotic Pressure

The aim of this study was to investigate whether the interstitial colloid osmotic pressure (COP(i)) of peritoneum is of importance for peritoneal fluid reabsorption during peritoneal dialysis (PD). For testing this hypothesis, a method to isolate interstitial fluid from the peritoneal membrane and to measure the interstitial COP(i) in the normal peritoneum and directly after the initiation of PD needed to be developed and validated. Eighteen female rats were anesthetized subcutaneously in the neck region with fentanyl-midazolam (1:1). Nylon wicks were implanted postmortem by means of a plastic catheter in the tissue just underneath the peritoneal surface. The characteristics of this fluid were compared with that isolated from wicks that were implanted in intermuscular spaces in hindlimb muscle and back subcutis. All wicks were removed after 20 min and centrifuged. The wick fluid was collected and analyzed in a colloid osmometer constructed for submicroliter samples, and interstitial fluid COP was compared with that of plasma. PD was initiated by injecting 20 ml of 3.86% glucose-containing PD fluid (Dianeal) into the peritoneal cavity, over a dwell time of 4 h. Control rats received no PD. The ratio of COP(i) to that of plasma (COP(p)) during control was 0.65 +/- 0.05 in peritoneum, 0.53 +/- 0.04 in muscle, and 0.59 +/- 0.05 in skin. After a PD dwell, the ratio was 0.29 +/- 0.03 in peritoneum, 0.54 +/- 0.08 in muscle, and 0.41 +/- 0.06 in skin. Thus, the COP ratio in peritoneum fell by 55% (P = 0.014) and in skin by 30% (P = 0.03), whereas the COP ratio in muscle was unchanged. The results suggest that acute PD results in a marked fall of the COP(i) in the peritoneal membrane, shifting the Starling equilibrium toward an absorptive state. The effect was restricted to the peritoneal membrane and, to some extent, the skin. It is speculated that the increase in peritoneal hydrostatic pressure after PD causes an increase in interstitial tissue volume, with primarily a dilution of interstitial colloids.

Vascular endothelial growth factor a and c gene expression in endometriosis*1

Angiogenesis is essential for the pathogenesis of endometriosis. Gene expression levels of vascular endothelial growth factor (VEGF) A and C in 10 eutopic endometrial, 23 normal peritoneal, and 62 endometriotic tissues surgically obtained from 47 women with endometriosis (group 2) were compared with those in 12 control eutopic endometrial and 9 normal peritoneal tissues from 15 women without endometriosis (group 1). VEGF-A mRNA expression levels in eutopic endometrium of group 2 were higher than those of group 1 throughout the menstrual cycle (P <0.01) and increased in the secretory phase. VEGF-A gene expression in peritoneal endometriotic lesion was statistically higher than that in normal peritoneum (P <0.01) and similar to that in eutopic endometrium of group 2. In contrast, gene expression levels of VEGF-C were relatively lower than those of VEGF-A in each lesion, and no cyclic variation was found. VEGF-A and C mRNA expression levels were significantly higher in ovarian endometriomas >6 cm in size than in those <6 cm in size. Immunohistochemical expression of VEGF-A and C was detected in the cytoplasm of glandular epithelial and stromal cells of ovarian endometrioma. These results suggest that endometriosis may arise from eutopic endometrium with higher levels of angiogenic activity possibly induced by VEGF-A in women with endometriosis. Moreover, VEGF-C as well as VEGF-A may be involved in the pathogenesis of ovarian endometrioma.

Vascular endothelial growth factor A and C gene expression in endometriosis

Angiogenesis is essential for the pathogenesis of endometriosis. Gene expression levels of vascular endothelial growth factor (VEGF) A and C in 10 eutopic endometrial, 23 normal peritoneal, and 62 endometriotic tissues surgically obtained from 47 women with endometriosis (group 2) were compared with those in 12 control eutopic endometrial and 9 normal peritoneal tissues from 15 women without endometriosis (group 1). VEGF-A mRNA expression levels in eutopic endometrium of group 2 were higher than those of group 1 throughout the menstrual cycle ( P <0.01) and increased in the secretory phase. VEGF-A gene expression in peritoneal endometriotic lesion was statistically higher than that in normal peritoneum ( P <0.01) and similar to that in eutopic endometrium of group 2. In contrast, gene expression levels of VEGF-C were relatively lower than those of VEGF-A in each lesion, and no cyclic variation was found. VEGF-A and C mRNA expression levels were significantly higher in ovarian endometriomas >6 cm in size than in those <6 cm in size. Immunohistochemical expression of VEGF-A and C was detected in the cytoplasm of glandular epithelial and stromal cells of ovarian endometrioma. These results suggest that endometriosis may arise from eutopic endometrium with higher levels of angiogenic activity possibly induced by VEGF-A in women with endometriosis. Moreover, VEGF-C as well as VEGF-A may be involved in the pathogenesis of ovarian endometrioma.

Hypoxia upregulates cyclooxygenase-2 and prostaglandin E2 levels in human peritoneal fibroblasts

Cyclooxygenases catalyze the rate-limiting step in prostaglandin synthesis. Mammalian cells contain at least two isozymes of cyclooxygenase: COX-1 and COX-2. The COX-1 gene is constitutively expressed in most tissues and the protein levels do not fluctuate in response to stimuli whereas the COX-2 gene is induced by a variety of agents, including growth factors, phorbol esters, and cytokines. We have previously begun to characterize differences between fibroblasts isolated from normal peritoneum and from adhesions, and have identified phenotypical differences between these two cell types from the same patients.

The differential expression of intercellular adhesion molecule-1 (ICAM-1) and regulation by interferon-gamma during the pathogenesis of endometriosis.

To establish an in vitro culture model of the endometrium and endometriotic lesions, and demonstrate the different expressions of intercellular adhesion molecule-1 (ICAM-1) in these lesions. Eight women with moderate to severe stages of endometriosis were enrolled. The specimens were collected from their eutopic endometrium, visually normal peritoneum, ovarian endometrioma and peritoneal endometriotic spots during the follicular phase of the menstrual cycle. ICAM-1 mRNA and protein were expressed by using reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, immunoblot, and immunocytochemistry. The results demonstrate that visually normal peritoneal cells and ovarian endometriomas of endometriotic patients can express high ICAM-1 mRNA. Normal peritoneal cells further expressed significant soluble ICAM-1 protein levels without cytokine stimulation. The eutopic endometrium expressed less soluble ICAM-1 protein, and ICAM-1 expressions increased in cultured stromal cells of eutopic endometrium, ovarian endometrioma, and peritoneal endometriotic spots under interferon-gamma (INF-gamma) stimulation. The ICAM-1 expression in visually normal peritoneal cells from women with endometriosis may play a role in the early implantation of peritoneal endometriosis. Peritoneal INF-gamma stimulation is significantly associated with ICAM-1 expression in endometriosis. Therefore, the differential expression and changes of ICAM-1 may be involved in the mechanism that can escape immunosurveillance and allow refluxed endometrial cells to spread and invade other location.

Regulation of expression of tissue plasminogen activator and plasminogen activator inhibitor-1 by dichloroacetic acid in human fibroblasts from normal peritoneum and adhesions

ObjectiveAs part of our ongoing studies to understand the biologic mechanisms of wound repair that lead to postoperative adhesions, we have identified characteristics of an adhesion phenotype that differs between fibroblasts that are obtained from human normal peritoneum and adhesions. In this study, we sought to examine whether stimulation of aerobic metabolism would alter differential expression of tissue plasminogen activator and plasminogen activator inhibitor–1, thereby creating a milieu likely to be less favorable to postoperative adhesion development. To examine this issue, we used a compound, dichloroacetic acid, that stimulates the pyruvate dehydrogenase complex, which causes pyruvate to be metabolized in the Kreb's cycle rather than being converted into lactate, thereby switching anaerobic to aerobic metabolism. Study designHuman fibroblasts from normal peritoneum and adhesions were cultured in the absence or presence of dichloroacetic acid (100 μg/mL) for 24 hours, under normal and hypoxic (2% 02) conditions. Real-time reverse transcriptase–polymerase chain reaction of tissue plasminogen activator, plasminogen activator inhibitor–1, and a housekeeping gene β-actin was performed with messenger RNA that was extracted from all treatment points. ResultsDichloroacetic acid stimulated normal peritoneal fibroblast tissue plasminogen activator messenger RNA expression under hypoxic conditions. In adhesion fibroblasts, dichloroacetic acid treatment enhanced tissue plasminogen activator messenger RNA expression under both normoxic and hypoxic conditions. Plasminogen activator inhibitor–1 messenger RNA expression was unaltered by dichloroacetic acid in normoxic normal peritoneal fibroblasts; but during culture under hypoxic conditions, dichloroacetic acid reduced plasminogen activator inhibitor–1 messenger RNA expression. Similarly, in adhesion fibroblasts, dichloroacetic acid reduced plasminogen activator inhibitor–1 messenger RNA expression under both normoxic and hypoxic conditions. As a result, in normal peritoneal fibroblasts under hypoxic conditions and in adhesion fibroblasts under normoxic and hypoxic conditions, dichloroacetic acid greatly increased the tissue plasminogen activator/plasminogen activator inhibitor–1 ratios. ConclusionThese findings confirm that fibroblasts from adhesions are characterized by reduced tissue plasminogen activator and increased plasminogen activator inhibitor–1 production. These observations are extended to show the stimulation of oxidative metabolism by dichloroacetic acid increases tissue plasminogen activator expression under hypoxic conditions. Dichloroacetic acid reduces plasminogen activator inhibitor–1 production by hypoxic normal peritoneal fibroblasts and adhesion fibroblasts under hypoxic conditions. The resultant increases in the tissue plasminogen activator/plasminogen activator inhibitor–1 ratios would favor the development of a fibrinolytic milieu, which would be expected potentially to limit postoperative adhesion development. Thus, regulation of metabolic activity of peritoneal cells may provide a target for future interventions for the reduction of the development of postoperative adhesions, particularly as intervention relates to the healing of peritoneal sites that previously had adhesions. (eg, sites of potential adhesion reformation).

Regulation of matrix metalloproteinase-1 and tissue inhibitor of matrix metalloproteinase-1 by dichloroacetic acid in human fibroblasts from normal peritoneum and adhesions

Objective To examine the role of stimulation of aerobic metabolism on the differential expression of matrix metalloproteinase–1 (MMP-1) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), which are differentially regulated in fibroblasts isolated from normal human peritoneum and adhesions. Design Tissue culture study. Setting University research laboratory. Patient(s) Human fibroblasts cultures from normal peritoneum and adhesions that were exposed to dichloroacetic acid (DCA; 0 and 100 μg/mL) for 24 hours under normal and hypoxic conditions. Intervention(s) Main outcome measure(s) Real-time reverse-transcription polymerase chain reaction of MMP-1, TIMP-1, and β-actin. Result(s) Dichloroacetic acid stimulated peritoneal fibroblast MMP-1 mRNA expression under normoxic conditions; this stimulation was lost during hypoxia. In adhesion fibroblasts, DCA increased MMP-1 mRNA expression; this effect was reversed by hypoxia. Expression of TIMP-1 mRNA was insignificantly increased by DCA in normal peritoneal and adhesion fibroblasts under normoxic conditions; however under hypoxic conditions, DCA reduced TIMP-1 mRNA expression from both. Conclusion(s) Regulation of metabolic activity of peritoneal cells may provide a target for future interventions for reduction of development of postoperative adhesions, particularly as it relates to healing of peritoneal sites that did not previously have adhesions as opposed to sites that underwent lysis of preexistent adhesions.

Is the Peritoneum a Significant Transport Barrier in Peritoneal Dialysis?

The anatomic peritoneum is often considered equivalent to the barrier between the dialysate and the blood, and is also called "the peritoneal membrane." Our hypothesis is that the normal peritoneum is not a significant barrier to solute or water flow. The goal of this study was to explore the effects of alteration of the anatomic peritoneum on the transperitoneal transport of water and solute. In vivo transport experiments were carried out in control and treated rats. Treatments consisted of frequent mixing of the peritoneal solution versus no mixing, drying the peritoneum prior to the experiment, or selective removal of the entire peritoneum. Transport experiments were carried out via a plastic chamber affixed to the parietal peritoneum. After measuring solute transport or osmotically induced filtration, the tissue underlying the chamber was collected and stained for histology. Mixing the chamber solution every 5 minutes versus no mixing over 90 minutes did not result in a significant change in the mass transfer coefficient for mannitol (MTCmannitol, n = 14, p > 0.25). Drying the peritoneum prior to the transport experiment did not significantly alter the MTC of albumin or mannitol (n = 17, p > 0.6; n = 19, p > 0.1, respectively). Manual drying did not remove or significantly alter the apparent peritoneal coating on the surface of the mesothelium. Removal of the entire peritoneum did not significantly alter the osmotically induced volume flux from the tissue, nor did it change the MTCmannitol (n = 9, p > 0.9; n = 9, p > 0.4, respectively). Mixing of the solution directly over the tissue, manual drying of the peritoneum, or removal of the entire peritoneum does not result in significant alterations in transport. We conclude that the anatomic peritoneum is relatively unimportant as a physical transport barrier in peritoneal dialysis.

Expression of transforming growth factor β1 in nerve fibers is related to dysmenorrhea and laparoscopic appearance of endometriotic implants

Objective To quantify the expression of transforming growth factor β1 in nerve fibers in endometriotic lesions and to correlate it with dysmenorrhea and appearance of endometriotic implants. Design Prospective comparative study. Setting University hospital. Patient(s) Peritoneal endometriotic specimens obtained from 35 patients diagnosed with endometriosis were compared with biopsies of normal peritoneum from 10 patients without endometriosis. Intervention(s) Endometriosis-associated dysmenorrhea for each patient was evaluated before surgery using a 10-point visual analog scale, which was followed by a laparoscopic staging of the patient's endometriosis. Main outcome measure(s) Immunohistochemical analysis of the peritoneal endometriotic specimens evaluated the maximal intensity of staining (INTMMAX) of TGFβ1, defined as higher staining intensity found within a selected structure. Result(s) When the nerve fibers of endometriotic lesions were compared with those of normal peritoneum, statistically significant differences were found in the INTMMAX of TGFβ1. Greater TGFβ1 INTMMAX was found in red lesions and deep endometriotic foci than in black lesions and normal peritoneum. A statistically significant relationship was found between the TGFβ1 INTMMAX score and dysmenorrhea; a relationship also was found to the color of the lesions. Conclusion(s) The physical appearance of endometriotic implants and the severity of dysmenorrhea appear to be related to the expression of TGFβ1 in nerve fibers.

Expression of transforming growth factor beta1 in patients with and without previous abdominal surgery.

Transforming growth factor beta1 (TGF-beta1) plays an important role in the formation of adhesions after abdominal operations. Prospective, observational study. University-based, tertiary referral center. Patients undergoing elective open abdominal operations were recruited and divided into 2 groups. Twenty-two patients with a history of abdominal surgery were designated as study patients, and 10 patients with no history of abdominal surgery served as controls. Samples of normal peritoneum, peritoneal scar tissues, and serum were obtained from all patients at the time of surgery. Samples were assayed for total TGF-beta1 expression using an enzyme-linked immunosorbent assay. Scar tissues expressed significantly greater amounts of TGF-beta1 (0.47 pg/ micro L) compared with normal peritoneal tissue from both study patients (0.29 pg/ micro L; P =.03) and controls (0.17 pg/ micro L; P =.002). Serum TGF-beta1 levels were also higher in study patients (1.71 pg/ micro L) compared with controls (1.22 pg/ micro L; P =.02). Neither adhesion nor serum TGF-beta1 expression correlated with time since last operation, total number of previous operations, or severity of intra-abdominal adhesions. These results suggest that TGF-beta1 may play an important role in human peritoneal adhesion formation.