Identification of epidermal growth factor, transforming growth factor-alpha, and epidermal growth factor receptor in surgically induced pelvic adhesions in the rat and intraperitoneal adhesions in the human

Changes in maternal serum transforming growth factor beta-1 during pregnancy: a cross-sectional study

Changes in circulating levels of maternal serum transforming growth factor beta-1 (TGF-β1), collected from 98 women (AGA) at different gestational ages (10–38 weeks) were measured and comparisons were made between levels in pregnant and nonpregnant controls and also between 10 women with small-for-gestational age (SGA) and 7 with appropriate-for-gestational age (AGA) fetuses. Maternal serum TGF-β1 levels at all stages of pregnancy were higher than those in normal healthy nonpregnant adults. The mean TGF-β1 levels in SGA pregnancies at 34-week gestation (32.5 + 3.2 ng/mL) were significantly less than those in AGA pregnancies (39.2 + 9.8 ng/mL) while at 38-week gestation, the levels were similar in the two groups (36.04 + 4.3 versus 36.7 + 7.0 ng/mL). This differential change in TGF-β1 levels is probably an important modulating factor in the aetiopathogenesis of abnormal intrauterine fetal growth.

A method for the consistent creation and quantitative testing of postoperative pelvic adhesions in a porcine model

INTRODUCTION

The assessment of methods for the prevention of postoperative pelvic adhesions is hampered by the lack of a quantifiable adhesion measurement technique. Currently available methods for adhesion model assessment rely on qualitative grading scales; a quantitative method would have many attendant benefits, including standardized reporting.

METHODS

A technique was developed to generate consistent and significant adhesions in a swine model that are suitable for quantitative assessment using a Material Testing System (MTS) machine platform. In this method, the uterine horns are cannulated and then attached to the pelvic sidewall using loose silk sutures. The underlying sidewall and adjacent uterine serosa are injured with electrocautery. Following a two-week survival the entire complex of uterine horn and sidewall are excised en bloc and prepared for MTS testing.

RESULTS

Extrication of the adhesion, as measured by the MTS platform, generates a quantitative assessment of adhesion strength that can be scaled and analyzed to produce several continuous variable descriptions.

DISCUSSION

This technique represents a novel quantitative method for adhesion assessment in an animal model. This quantitative technique may then be applied to accurately assess a range of adhesion prevention techniques, producing results which can be standardized for comparison.

Impact of aromatase inhibitors on adhesion formation in a rat model

OBJECTIVE

To investigate the antiadhesion potential of tamoxifen and anastrozole in a rat uterine horn model.

DESIGN

Experimental animal study.

SETTING

University animal laboratory.

ANIMAL(S)

Forty-five female Wistar albino rats.

INTERVENTION(S)

We examined the effects of tamoxifen and anastrozole to reduce the extent and severity of postoperative adhesions in a rat uterine horn model: the control group received no therapy while the second and third groups received 500 mug/day tamoxifen and 0.2 mg/kg/day anastrazole, respectively, through an enteric tube, starting 5 days before surgery. These protocols were continued for 14 days after the surgery until the rats were killed.

MAIN OUTCOME MEASURE(S)

Adhesions were scored according to their extent and severity, and specimens were also evaluated and scored histologically according to the following features: inflammation, fibroblastic activities, foreign body reaction, collagen formation, and vascular proliferation.

RESULT(S)

Anastrozole had the lowest mean adhesion scores, and these scores were significantly different from those of the controls. However, there were no statistically significant differences between control and tamoxifen groups and between tamoxifen and anastrozole groups. Histologic scores were lowest in the anastrozole group, which were statistically different from those of the tamoxifen and anastrozole groups, whereas scores of the control group were not statistically different from those of the tamoxifen group.

CONCLUSION(S)

Anastrazole decreased postsurgical adhesion scores by both visual scores and histologic analyses in a rat model. Further experimental and clinical trials are required to confirm these results.

Experimental manipulation of transforming growth factor-beta isoforms significantly affects adhesion formation in a murine surgical model

Transforming growth factor-beta (TGF-beta), a multifunctional growth factor, represents three mammalian isoforms, TGF-beta1, TGF-beta2, and TGF-beta3. In cutaneous wound healing, combined neutralization of TGF-beta1 and -beta2 or addition of TGF-beta3 reduces scar formation. Here, we investigated whether experimental manipulation of TGF-beta isoforms reduced adhesion formation after injury to the peritoneum. Adhesions were produced in mice by surgical abrasion of adjacent serosa followed by close apposition. In the first part of this study, a detailed analysis of TGF-beta isoform distribution was performed through immunolocalization. TGF-beta isoforms clearly showed a unique temporal and spatial pattern of expression after peritoneal wounding. Based on this pharmacokinetic data, we next administered neutralizing antibodies to TGF-beta1 and -beta2 or exogenous TGF-beta3 peptide by local application and intraperitoneal injection at various times before and after surgery. At day 7 after surgery, addition of neutralizing antibodies to both TGF-beta1 and -beta2 significantly reduced the number and size of adhesions (P < 0.05) compared with the vehicle control. By contrast, exogenous addition of TGF-beta3 either had no effect or increased adhesion formation compared to the vehicle control. In conclusion, these results show that by blocking both TGF-beta1 and TGF-beta2 using neutralizing antibodies, it is possible to prevent abdominal adhesion formation.

Plasminogen activator/plasminogen activator inhibitor-1 and cytokine modulation by the PROACT System

OBJECTIVE

To examine the effects of the PROACT treatment on the fibrinolytic system and inflammatory cytokines in human peritoneum.

DESIGN

Controlled clinical study.

SETTING

University hospital.

PATIENT(S)

Nine subjects undergoing laparotomy had peritoneal samples taken at the incision.

INTERVENTION(S)

The PROACT applicator was inserted through the peritoneal incision, and treatment of peritoneum was performed twice. A peritoneal sample was taken from one treated area. At closure, the second treated sample and an additional control sample were taken. All four samples were snap frozen in liquid nitrogen. Samples were homogenized and protein content extracted.

MAIN OUTCOME MEASURE(S)

Concentrations of total and active transforming growth factor-beta 1 (TGF-beta1), tumor necrosis factor-alpha (TNF-alpha), tissue-type plasminogen activator (t-PA), urokinase plasminogen activator (uPA), and plasminogen activator inhibitor 1 (PAI-1) were obtained.

RESULT(S)

Total TGF-beta1 at opening was 30% less in treated samples. At closure, active TGF-beta1 increased significantly (163%) in control samples and not in treated samples. Tumor necrosis factor alpha was detectable only in control samples at closure. During surgery, tPA levels showed a marked decrease in control samples vs. a small increase in treated samples. Levels of uPA increased significantly only in the control samples. In control samples, tPA/PAI-1 ratio was two thirds of treated sample ratio.

CONCLUSION(S)

Heating of the peritoneum with the PROACT System modulates the biologic tissue response to induce effects that would be consistent with inhibition of postoperative adhesion development.

Increased expression of interferon-inducible protein-10 during surgically induced peritoneal injury

Interferon-inducible protein 10 (IP-10) is a key regulator of neutrophils, monocytes, and lymphocytes, cells infiltration whose secretory products play a key role in peritoneal wound healing. The objective of the present study was to determine whether IP-10 is expressed by parietal peritoneum and whether its temporal and spatial expression is altered following surgically induced peritoneal injury during healing. Peritoneal sidewall injuries were induced in mice (N = 60), and the severity of adhesions were graded at 12 hours and 1, 2, 4, and 7 days postsurgery. After collection of peritoneal washes, the injured peritoneum with associated adhesion and intact parietal peritoneum were collected to determine IP-10 mRNA and protein expression using quantitative reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemistry. Peritoneal injury resulted in adhesion formation with increased severity by day 7 postsurgery. The intact parietal peritoneum expressed IP-10 mRNA, whose level of expression significantly increased following peritoneal injury and reached a maximum at day 4 (p = 0.001), declining to the uninjured control levels by day 7 post-injury. The level of IP-10 in peritoneal washes also increased as a result of peritoneal injury. Immunohistochemically, IP-10 was localized to various inflammatory and immune cells, adhesion fibroblasts, and mesothelial cells, and its intensity increased during the course of wound healing. In conclusion, we showed that parietal peritoneum expresses IP-10 and peritoneal tissue injury results in an elevated level of its expression throughout the early phase of wound healing. The results suggest that IP-10 and its elevated expression may play a role in peritoneal cellular activities that influence the early phases of tissue repair and, possibly, the development of peritoneal adhesions.

Halofuginone, an inhibitor of collagen type I synthesis, prevents postoperative adhesion formation in the rat uterine horn model

OBJECTIVE

The objective of this study was to evaluate the effects of halofuginone-a specific inhibitor of collagen type I synthesis-in preventing uterine horn adhesion formation in rats.

STUDY DESIGN

Adhesions were induced by scraping the rat uterine horns until capillary bleeding occurred. Halofuginone was either injected intraperitoneally or administered orally. The number and severity of the adhesions were scored. Collagen alpha1(I) gene expression was evaluated by in situ hybridization; total collagen was estimated by sirius red staining. Collagen synthesis in response to halofuginone was evaluated in cells cultured from the adhesions.

RESULTS

Regardless of the administration procedure, halofuginone reduced significantly the number and severity of the adhesions in a dose-dependent manner. Halofuginone prevented the increase in collagen alpha1(I) gene expression observed in the rats that underwent this procedure, thus affecting only the newly synthesized collagen but not the resident collagen. In cells derived from rat uterine horn adhesions, halofuginone induced dose-dependent inhibition of collagen synthesis.

CONCLUSIONS

Upregulation of collagen synthesis appears to play a critical role in the pathophysiologic mechanism of adhesion formation. Halofuginone could be used as an important means of understanding the role of collagen in adhesion formation and might become a novel and promising antifibrotic agent for preventing adhesion formation after pelvic surgery.

Immunomodulation with interleukin-10 and interleukin-4 compared with ketorolac tromethamine for prevention of postoperative adhesions in a murine model

OBJECTIVE

To assess the effects of two macrophage down-regulating cytokines (interleukin [IL]-10 and IL-4) and the nonsteroidal anti-inflammatory drug ketorolac tromethamine on postoperative adhesion formation.

DESIGN

Randomized controlled trial.

SETTING

Research center vivarium.

ANIMAL(S)

Six-week-old Swiss Webster mice.

INTERVENTION(S)

One hundred eighty animals were randomized to serve as nonsurgical controls or to undergo a standardized adhesion-inducing procedure. Subsequently, animals were randomized to nine different treatment groups to receive no injections, phosphate-buffered saline (PBS) only, IL-10, IL-4, ketorolac, IL-10 plus IL-4, IL-10 plus ketorolac, IL-4 plus ketorolac, or all three agents.

MAIN OUTCOME MEASURE

Adhesion scores on postoperative day 10.

RESULT(S)

Postoperative adhesion scores were significantly reduced in all groups of animals treated with IL-10 or ketorolac. Animals treated with IL-4 showed a nonsignificant trend toward reduction of adhesions. There were significantly more animals with adhesion scores of < or = 3 in the IL-10 and ketorolac treatment groups than in the control groups receiving no treatment or PBS only.

CONCLUSION(S)

Although treatment with IL-10 and ketorolac did not completely prevent adhesion formation, treatment with these drugs did lead to a significant reduction in adhesion formation. Adhesions also tended to be thin and filmy rather than thick and vascular. Addition of IL-4 did not augment these effects.

An inhibitor of cell proliferation associated with adhesion formation is suppressed by N,O-carboxymethyl chitosan

Surgical adhesions are a major cause of morbidity and mortality. The ideal barrier agent will both minimize adhesions and provide a milieu for the regeneration of the mesothelium lining of the abdominal and thoracic cavities. N,O-Carboxymethylchitosan (NOCC), a derivation of chitin that markedly reduces adhesions, may function to modulate intracellular signals such as growth factors and cytokines in the inflammatory exudate. Since transforming growth factor-beta is implicated in the fibrotic process, we investigated the possibility that NOCC's effects on adhesion formation reflects a modulation of TGF-beta activity. Using a biological assay for inhibition of cell proliferation to detect TGF-beta activity, we demonstrate that NOCC suppresses the levels of an inhibitor of cell proliferation released into serum and peritoneal exudates after cecal abrasion in the rat. However, this activity was distinct from known forms of TGF-beta as determined using both TGF-beta-neutralizing antisera and a TGF-beta-resistant cell proliferation assay. Thus at least one potential effect of NOCC involves a mechanism distinct from TGF-beta inhibition.

Pelvic adhesions contain sex steroid receptors and produce angiogenesis growth factors

OBJECTIVE

To evaluate female pelvic adhesion tissue for the presence of estrogen receptor (ER), progesterone receptor (PR), basic fibroblastic growth factor (basic-FGF), and vascular endothelial growth factor (VEGF).

DESIGN

Descriptive study.

SETTING

Patients at a tertiary medical center.

PATIENTS

Female reproductive age patients undergoing gynecologic surgery who were not receiving hormonal therapy.

INTERVENTIONS

Female reproductive tract peritoneal adhesion tissue was excised, frozen, and sent for immunohistologic evaluation.

MAIN OUTCOME MEASURE

Presence of ER, PR, basic-FGF, and VEGF in adhesion tissue.

RESULTS

Nineteen of 19 specimens were positive for PR; 16 of 19 specimens were positive for ER, which was present in a variety of the different cell types constituting adhesion. Vascular endothelial growth factor and basic-FGF were detected in endothelial cells of blood vessels supplying this tissue as well as in mesothelial cells.

CONCLUSION

Adhesion tissue contains ER, PR, and growth factors that may be important in the genesis of the permanent fibrovascular bands between pelvic organs. This supports the theoretical possibility of hormonal manipulation of these tissues to negatively influence postoperative pelvic adhesion formation.