Amnio-allantoic fluid exchange for the prevention of intestinal damage in gastroschisis. III: Determination of the waste products removed by exchange

Fetal Surgery for Gastroschisis—A Review with Emphasis on Minimally Invasive Procedures

(1) Background: The morbidity of gastroschisis is defined by exposure of unprotected intestines to the amniotic fluid leading to inflammatory damage and consecutive intestinal dysmotility, the viscero-abdominal disproportion which results in an abdomen too small to incorporate the herniated and often swollen intestine, and by associated pathologies, such as in complex gastroschisis. To prevent intestinal damage and to provide for growth of the abdominal cavity, fetal interventions such as amnio exchange, gastroschisis repair or covering have been evaluated in several animal models and human trials. This review aims to evaluate the reported techniques for the fetal treatment of gastroschisis by focusing on minimally invasive procedures. (2) Methods: We conducted a systematic database search, quality assessment and analyzed relevant articles which evaluate or describe surgical techniques for the prenatal surgical management of gastroschisis in animal models or human application. (3) Results: Of 96 identified reports, 42 eligible studies were included. Fetal interventions for gastroschisis in humans are only reported for EXIT procedures and amnio exchange. In animal models, particularly in the fetal sheep model, several techniques of open or minimally invasive repair of gastroschisis or covering the intestine have been described, with fetoscopic covering being the most encouraging. (4) Discussion: Although some promising minimally invasive techniques have been demonstrated in human application and animal models, most of them are still associated with relevant fetal morbidity and mortality and barely appear to be currently applicable in humans. Further research on specific procedures, instruments and materials is needed before any human application.

Metabolomics analysis of annual killifish (Austrofundulus limnaeus) embryos during aerial dehydration stress

The annual killifish, Austrofundulus limnaeus, survives in ephemeral ponds in the coastal deserts of Venezuela. Persistence through the dry season is dependent on drought-resistant eggs embedded in the pond sediments during the rainy season. The ability of these embryos to enter drastic metabolic dormancy (diapause) during normal development enables A. limnaeus to survive conditions lethal to most other aquatic vertebrates; critical to the survival of the species is the ability of embryos to survive months and perhaps years without access to liquid water. Little is known about the molecular mechanisms that aid in survival of the dry season. This study aims to gain insight into the mechanisms facilitating survival of dehydration stress due to aerial exposure by examining metabolite profiles of dormant and developing embryos. There is strong evidence for unique metabolic profiles based on developmental stage and length of aerial exposure. Actively developing embryos exhibit more robust changes; however, dormant embryos respond in an active manner and significantly alter their metabolic profile. A number of metabolites accumulate in aerial-exposed embryos that may play an important role in survival, including the identification of known antioxidants and neuroprotectants. In addition, a number of unique metabolites not yet discussed in the dehydration literature are identified, such as lanthionine and 2-hydroxyglutarate. Despite high oxygen availability, embryos accumulate the anaerobic end product lactate. This paper offers an overview of the metabolic changes occurring that may support embryonic survival during dehydration stress due to aerial incubation, which can be functionally tested using genetic and pharmacological approaches.

The correlation between the time spent in utero and the severity of bowel matting in newborns with gastroschisis

BACKGROUND

Optimal timing of delivery in fetuses with gastroschisis (GS) is unknown. Some favor early induced delivery to prevent bowel injury. This study evaluates the correlation between bowel injury and the gestational age at birth using the Gastroschisis Prognostic Score (GPS).

METHODS

A national database was analyzed from 2005 to 2013. Patients were pooled based on their gestational age at birth. The mean GPS and % of patients with severe bowel matting were tabulated for each week in utero. Regression modeling was used to evaluate the relationship between the dependent (severe matting and GPS) and independent (gestational age) variables and the R(2) coefficient of determination was derived to evaluate model strength. Additional factors influencing the timing of delivery were evaluated.

RESULTS

Of 780 cases, 88 were excluded because of missing data. A linear relationship is seen between increasing gestational age and decreasing bowel matting (R(2)=0.66) and GPS (R(2)=0.72). For every week in utero, the % of patients with severe matting decreases by 3.6%.

CONCLUSION

Early induced delivery simply to protect the bowel from ongoing in utero damage appears unfounded and should be reserved for evidence of closing gastroschisis or traditional obstetrical/fetal indications.

Intra-amniotic administration of urinary trypsin inhibitor preserves intestinal contractility in meconium induced intestinal damage in chick embryos with gastroschisis

BACKGROUND

Intestinal damage causes intestinal dysmotility in gastroschisis. Urinary trypsin inhibitor (UTI) has been shown to prevent intestinal damage in chick embryos with gastroschisis. The effect of intra-amniotic administration of UTI on intestinal motility in gastroschisis has not been investigated.

METHODS

Five-day-old fertilized chick embryos were used. Gastroschisis was created through the amniotic cavity without opening the allantoic cavity. There were six groups; control, gastroschisis only, gastroschisis plus meconium and three treatment groups. In the treatment groups, 100 IU/mL, 200 IU/mL and 400 IU/mL UTI were instilled into the amniotic cavity of the gastroschisis plus meconium embryos, respectively. Serosal thickness of the intestines in each group was measured histopathologically. The contractions of the intestines were evaluated by in vitro organ bath technique and the responses were expressed as maximal contraction induced by acetylcholine.

RESULTS

The serosal thickness was significantly increased in the gastroschisis plus meconium, 100 IU/mL, 200 IU/mL UTI groups compared to control and gastroschisis only groups. The serosal thickness of the 400 IU/mL UTI group was similar to control and gastroschisis only groups. Contractility of the intestines was diminished in the gastroschisis plus meconium, 100 IU/mL and 200 IU/mL UTI groups. There was no significant difference regarding contractility among control, gastroschisis only and 400 IU/mL UTI groups.

CONCLUSION

Intra-amniotic administration of UTI preserves intestinal contractility in chick embryos with gastroschisis. However, preservation of intestinal dysmotility by using UTI in the human gastroschisis cases needs further experimental and clinical trials.

Advances in surgery for abdominal wall defects: gastroschisis and omphalocele

Abdominal wall defects (AWDs) are a common congenital surgical problem in fetuses and neonates. The incidence of these defects has steadily increased over the past few decades due to rising numbers of gastroschisis. Most of these anomalies are diagnosed prenatally and then managed at a center with available pediatric surgical, neonatology, and high-risk obstetric support. Omphaloceles and gastroschisis are distinct anomalies that have different management and outcomes. There have been a number of recent advances in the care of patients with AWDs, both in the fetus and the newborn, which will be discussed in this article.

Evaluation of diluted amniotic fluid effects on histological changes of intestine of rabbit fetus with gastroschisis

Amniotic fluid exchange is a method for prevention of intestinal damage in gastroschisis, but its techniques are different in studies. We investigated the effects of amnioinfusion exchange on histological changes of intestine and feasibility and safety of amniotic fluid exchange through central vein catheter (CVC) placed in pregnant rabbit uterus. A total of 15 pregnant New Zealand white rabbits were selected. Fetuses were randomly divided into three groups (case, control, sham). On gestational day 25, under general anesthesia with midline laparotomy, the graved bicornuate uterus was exposed. In controls, fetus abdomen was opened by a transverse incision in right lower quadrant region and intestines were eviscerated. In cases, after intestine evisceration, a central venous catheter was passed from mother skin and uterus and fixed to uterus wall. In shams, fetus was delivered on gestational day 32 and its abdomen was opened. In case group, after operation, 1-2 cc of warm saline solution was replaced through catheter every 6 h. On gestational day 32, fetuses of case and control groups were delivered. Mucosal and serosal thickness, muscle thickness, fibrin deposition, serosal collagen and ganglia were compared. Ten fetuses as shams, 7 fetuses as controls and 7 fetuses as case group were studied. Serosal thickness was 4.5 +/- 3.6 microm in shams, 64.2 +/- 28.7 microm in controls and 6 +/- 4.1 microm in cases. Serosal thickness in control group was higher than sham (P < 0.001) and case (P < 0.002) groups. In case group, infiltration of inflammatory cells with mild edema without fibroblast infiltration was seen. Application of the CVC technique was found to be a simple procedure that effectively decreased serosal inflammatory response of intestine in gastroschisis.

Amniotic fluid ferritin as a marker of intestinal damage in gastroschisis: a time course experimental study

BACKGROUND/PURPOSE

Intestinal damage (ID) is closely related to morbidity and mortality in gastroschisis. This study was performed to determine the intraamniotic substances that may correlate ID and also to verify their time course levels that would be useful for determining when ID starts in gastroschisis.

METHODS

In this study, 13-day-old fertilized chick eggs were used. The amnioallantoic membrane was perforated to create amnioallantoic cavity in all embryos. Gastroschisis was created in gastroschisis group to simulate human gastroschisis. Amnioallantoic fluid samples were collected from the embryos on the 13th to 19th gestational days, and the intestines of each group were harvested for evaluation. Amnioallantoic levels of interleukin-8, ferritin, alkaline phosphatase, and amylase were measured. Serosal thickness of the intestines in each group was evaluated.

RESULTS

Increasing amnioallantoic fluid levels of interleukin-8, alkaline phosphatase, and amylase were found in both groups. In contrast to control group, ferritin levels, as a sign of inflammation, were found increased only in gastroschisis group. Histopathologic examination of intestines in the gastroschisis group showed a significant increase in the serosal thickness especially after the 16th day.

CONCLUSION

Increases in amnioallantoic fluid levels of ferritin show promise as a marker for determining ID encountered in gastroschisis but warrant further investigation.

[Prenatal care and postnatal outcome for fetuses with laparoschisis]

OBJECTIVES

To assess the relevance and the quality of gastroschisis's care in a mid level referral centre.

METHOD

A retrospective analysis was performed for infants diagnosed or born with gastroschisis between 1992 and 2003 at the Citadelle hospital, Department of Obstetrics and Gynaecology, University of Liège.

RESULTS

Twenty-four cases of gastroschisis were identified. For 22 of them (92%) antenatal sonographic diagnosis was performed at a mean gestational age of 23 weeks. Antenatal diagnosis did not allow to identify additional malformation or chromosomal anomaly. Postnatal diagnosis allows to identify 3 infants with minor cardiac anomalies without functional consequence and one X fragile syndrome. One pregnancy was electively terminated at 24 weeks and one late intrauterine death was reported at 35 weeks. Bowel atresia, stenosis or ischemia were present at birth for 8 cases (33%). Out of 24 cases 22 were live born. 10 infants out of 22 (45%) underwent uncomplicated primary surgical repair. Three infants out of 22 (14%) underwent delayed closure without complications. Nine infants out 22 (41%) underwent multiple surgery (2 to 6). In this group all had postnatal complications, some with multisystem complications, including 3 deaths, 6 with infectious complications, 5 with gastrointestinal complications and 2 with genitourinary or haematological complications. Hospital stay range from 19 to 378 days (median, 51 days). Length of stay and time to full enteral feeding were longer if oligohydramnios or sonographic signs of intestinal damage were found. Among infants born before 35 weeks, only those with intestinal damage at birth had length of stay or time to full enteral feeding longer. Out of 22 live born infants 19 survived (86%) after one year. Survival rate without handicap due to gastroschisis is 84%.

CONCLUSION

Sonographic examination is a valid method for prenatal diagnosis and surveillance. Our survival rate agrees with recent data in the literature. It has to be noticed that hospital stay is lengthy and complications are frequent. The most important prognostic factor is the condition of the bowel at birth and there is no antenatal means to predict severe damage.

Amnioexchange for fetuses with gastroschisis: is it effective?

BACKGROUND/PURPOSE

Amniotic fluid of fetuses with gastroschisis (GS) contains inflammatory mediators, gastrointestinal, and urinary waste products. Dilution and removal of such harmful substances have been advocated to prevent damage to the herniated intestine. We evaluated the effectiveness of serial amnioexchange procedures in 8 consecutive fetuses with GS.

METHODS

Amnioexchange was performed bimonthly during the third trimester. Amniotic fluid collected before each procedure was tested for pH, osmolarity, urea, creatinine, cystatin-C, proteins, albumin, bilirubin, biliary salts, pancreatic amylase, serum amyloid A, C-reactive protein, alanine transaminase (ALT), alcaline phosphatase (ALP), gamma-glutamyl transpetidase (gammaGT), tumor necrosis factor alpha, interleukin 2, interleukin 6, epidermal growth factor, transforming growth factor beta, and myeloperoxidase.

RESULTS

A total of 25 samples (median, 3 per fetus) were examined. Biochemical or inflammatory markers did not correlate with gestational age, nor was any trend observed in values from individual patients during the course of amnioexchange treatment. There was no correlation between biochemical or inflammatory markers and clinical outcome, including time to full enteral feeding.

CONCLUSIONS

Serial amnioexchanges did not modify the biochemical or inflammatory status of amniotic fluid nor appeared to prevent injury to the herniated gut. Because repeated amnioexchanges may carry some risks, their use in fetuses with GS is not recommended outside the setting of a prospective randomized trial.

Effects of intrauterine treatment on interstitial cells of Cajal in gastroschisis

AIM

An experimental study was performed to investigate the effects of amnio-allantoic fluid exchange and intrauterine bicarbonate treatment on intestinal damage and interstitial cells of Cajal (ICC) in gastroschisis.

MATERIALS AND METHODS

Thirteen-day-old fertilized chick eggs were randomly allocated into 4 groups as control, gastroschisis, gastroschisis + amnio-allantoic fluid exchange, and gastroschisis + bicarbonate treatment groups. In the treatment groups, amnio-allantoic exchange and bicarbonate treatments were performed for 3 days, after creating gastroschisis. Specimens were processed for hematoxylin-eosin and c-kit immunohistochemistry on the 18th day of incubation, after macroscopic examination. The intestines were evaluated with light microscopy for the presence of mucosal congestion and muscular and serosal edema. Mean muscular thickness and density of ICC were measured.

RESULTS

Mean muscular thickness significantly increased in the gastroschisis group when compared with control and treatment groups. Labeling intensity, morphology, and localization of the ICC were similar in all groups. Mean ICC density significantly decreased in the gastroschisis group when compared with the control group (P < .01), and it significantly increased after amnio-allantoic fluid exchange treatment (P < .01).

CONCLUSIONS

The decrease in ICC density encountered in damaged intestinal loops in gastroschisis was prevented with intrauterine treatment. The beneficial effects of amniotic exchange on intestinal motility may depend on both prevention of intestinal damage and preservation of ICC density and function. The density of ICC might be a reliable numeric parameter both to predict intestinal motility disorders in gastroschisis and to compare the effectiveness of intrauterine treatment methods.

Urinary trypsin inhibitor present in fetal urine prevents intraamniotic meconium-induced intestinal damage in gastroschisis

BACKGROUND/PURPOSE

Contact with amniotic fluid causes intestinal damage in gastroschisis, and intraamniotic meconium has been shown to be responsible. Meconium has been shown to contain a significant amount of IL-8, which may be the responsible cytokine for harmful effects of meconium. Neonatal urine contains high amount of urinary trypsin inhibitor (UTI) compared with adult human urine. Urinary trypsin inhibitor has been shown to exert inhibitory effects on IL-8. Therefore, far from being destructive, presence of fetal urine in the amniotic fluid might be beneficial because human urine contains UTI. An experimental study has been performed to investigate whether presence of intraamniotic human urine (consequently UTI) besides meconium is beneficial on intestines of chick embryo with gastroschisis.

METHODS

Five-day-old fertilized chick eggs were used. Gastroschisis was created through amniotic cavity without opening the allantoic cavity. Sterile urine and meconium were obtained from newborn humans. Study was conducted in 2 stages. In the first stage, gastroschisis was created, and meconium suspensions at minimal harmful meconium concentration were prepared using natural and denatured human neonatal urine and instilled into the amniotic cavity. In the second stage of study, various concentrations of UTI plus meconium suspension at minimal harmful meconium concentration was instilled into the amniotic cavity.

RESULTS

Serosal thickening, inflammation, and focal fibrin deposits were observed in intestines of the groups with meconium and meconium in denatured urine. Histopathologic features of intestines of the group with meconium in natural urine did not differ from the intestines of the control group. Histopathologic examination of intestines of groups with meconium and meconium plus 50 U/mL UTI showed serosal thickening, inflammation, focal fibrin, and collagen deposits. Histopathologic features of intestines of the groups with 1:400 intraamniotic meconium plus 100 and 200 U/mL UTI did not differ from the intestines of control group.

CONCLUSION

Urinary trypsin inhibitor 100 U/mL prevented the intestinal damage via inhibiting IL-8, which is contained by 1:400 concentration of meconium. Therefore, besides the existence of threshold level of meconium, the existence of UTI, which is capable of inhibiting IL-8 contained by threshold level of meconium, may be a factor in the occurrence of intestinal damage in gastroschisis.

The timing of delivery of infants with gastroschisis influences outcome

BACKGROUND

The delayed onset of intestinal function in children with gastroschisis may be because of the injurious effects of amniotic fluid on the exposed bowel. This has led to consideration of early delivery to minimize intestinal damage and improve outcome, although this has not been carefully evaluated. The authors hypothesized that timing of delivery influences outcome in children with gastroschisis, and sought to evaluate the relative impact of factors that predict outcome in this disease.

METHODS

All consecutive patients with gastroschisis (1992-2002) were divided into those delivered before ("early") or after ("late") 36 weeks. Bowel peel was described as "thin" or "thick," based on operative reports. Individual measures were analyzed by univariate analyses (chi2 /Student's t test), and logistic regression was used to identify significant factors for the length of stay (LOS) longer than the population average of 55 days.

RESULTS

In 75 patients, 53.4% were "early" and 46.6% were "late." Groups were similar with respect to maternal age, birth weight, delivery mode, sex, and associated anomalies. Thickness of bowel peel was not affected by delivery time, yet "early" patients had significantly longer LOS and time to enteral feeds. Significant predictors of LOS more than 55 days included gestational age of 36 weeks or younger, time to enteral feeds of more than 26 days, and associated anomalies. Nonsignificant predictors included size of the defect, thickness of bowel peel, and need for silo.

CONCLUSIONS

Delivery before 36 weeks is associated with longer hospitalization and increased tune to attainment of full feeds compared with later delivery. Fetal well-being should thus be the primary determinant of delivery for gastroschisis, as opposed to considerations regarding possible injurious effects to the bowel of prolonged gestation.

The effect on the intestines of continuous release of methylene blue from a drug delivery system: an experimental study in a chick embryo gastroschisis model

Increased small bowel nitric oxide synthase (NOS) activity has been suspected as a cause of postnatal intestinal dysmotility in gastroschisis. The effect of continuous delivery of methylene blue loaded polymer (MBLP) hydroxy-propyl methyl cellulose-ethyl cellulose (HPEC-MC) and daily injection of methylene blue (MB) on the intestinal damage (ID) was evaluated using a chick embryo gastroschisis model. Fourteen-day-old fertilized chick eggs were divided into five groups. In the control (C) group, no intervention was performed. In the sham (S) group, the allantoic and amniotic membranes were opened to create a common cavity that resembles the amniotic cavity in human. In the gastroschisis only (GO) group, a defect in the abdominal wall of the embryo was made, and intestinal loops were exteriorized following connection of amniotic and allantoic cavities. In the gastroschisis plus methylene blue (G+MB) group, gastroschisis was created and MB administered into the amnioallantoic cavity (AAC) by daily injections for 5 days. In the gastroschisis plus methylene blue loaded polymer (G+MBLP) group, MBLP was placed into AAC after gastroschisis was created. At the end of the 19th day of incubation, intestinal morphological changes were investigated macroscopically and microscopically. Although the survival rates were decreased in the chick embryos with creation of gastroschisis compared with C and S groups ( p<0.001), the survival rates were increased in G+MBLP group (76.92%) when compared with the GO group (41%) ( p<0.001). Because of multiple intervention of embryos, higher mortality was observed in the G-MB group (75.61%). Macroscopic and microscopic scores of ID and mean intestinal wall thickness were significantly higher in the GO group when compared with C, S, G+MB, and G+MBLP groups ( p<0.001). The mean score of intestinal ganglia morphology was significantly increased and the total number of ganglion cells was significantly decreased in the GO group when compared with C, S, G+MB, and G+MBLP groups ( p<0.001). It is possible to decrease intrauterine intestinal morphological changes in gastroschisis by inhibiting NOS. As a first preliminary study, we believe that use of MBLP may be an alternative for fetal treatment by eliminating the harmful effects of multiple interventions or amniotic fluid exchanges.

Prenatal management of gastroschisis: the place of the amnioexchange procedure

Gastroschisis is a malformation of the anterior abdominal wall that consists of a right paraumbilical defect with bowel loops bathed in the amniotic fluid. The survival rate is now greater than 90% and the prognosis relies mainly on morbidity attributable to bowel dysfunction. Recent research has examined gastrointestinal waste present in amniotic fluid that induces bowel toxicity and an inflammatory process. The amnioexchange procedure (changing the amniotic fluid regularly) involves a new therapeutic approach: reducing bowel injuries in the fetuses. This article shows that there is an inflammatory reaction in human gastroschisis and in the authors' model, and that the clinical and biological data plead for the practice of amnioexchange in human beings. A randomized, controlled study is now needed.

Effects of amnio-allantoic fluid exchange on bowel contractility in chick embryos with gastroschisis

BACKGROUND/PURPOSE

Intestinal damage in patients with gastroschisis is characterized by bowel wall thickening, intestinal dilatation, mesenteric shortening, and a fibrous peel. The prevention of intestinal damage in gastroschisis by amnio-allantoic fluid (AAF) exchange has been reported using histologic and macroscopic evaluation of intestines, but the effects of this treatment on bowel contractility have not been investigated. The current study was performed to determine the effect of AAF exchange on the intestinal contractility in chick embryos with gastroschisis.

METHODS

Thirteen-day-old fertilized chick eggs were used. Gastroschisis was created through amnio-allantoic cavity. There were 3 study groups: control group, gastroschisis-only group, and gastroschisis-plus-exchange group. The bowels were evaluated by an in vitro muscle strip technique, and the response was expressed as a percentage of the maximum acetylcholine evoked contraction (E(max)) in each tissue obtained. Additionally, parasympathetic ganglion cells per 10 plexus at the intestinal wall were counted. Differences between groups were analyzed by analysis of variance (ANOVA) followed by Tukey-Kramer. Probabilities of less than 5% were considered significant.

RESULTS

The intestines were thickened and covered by fibrous peel in the gastroschisis-only group when compared with the control group and the gastroschisis exchange group morphologically. There was a statistically significant decrease in contractility in the gastroschisis-only group compared with the control group (P <.05). It exerted 42.03 +/- 46.73% contraction of control group's E(max). This decrease in contractility was significantly reversed in the exchange group (P <.05; E(max) value of gastroschisis plus exchange group was 71.45 +/- 23.54% of control group's E(max)). Although the number of ganglia per 10 plexus was 76.7 +/- 4.3 in the control group, it was measured 28% less in the gastroschisis-only group (P <.05). There was no significant difference between the ganglion numbers of control and exchange groups.

CONCLUSIONS

Prenatal AAF exchange treatment prevents decreased bowel contractility in gastroschisis. Gastroschisis does not affect intestinal ganglia morphology, but the number of ganglion cells decreases. AAF exchange prevents these functional and morphologic adverse effects of disease. By these findings the expectancy of a better clinical result in gastroschisis with intrauterine pretreatment by amniotic fluid exchange increases.

Induction of fetal diuresis with intraamniotic furosemide increases the clearance of intraamniotic substances: An alternative therapy aimed at reducing intraamniotic meconium concentration

BACKGROUND/PURPOSE

Contact with amniotic fluid (AF) causes intestinal damage in gastroschisis. Intraamniotic meconium has been shown to be responsible for intestinal damage, and occurrence of this damage has been shown to depend on the concentration of intraamniotic meconium. When intraamniotic meconium concentration is lowered below threshold level by exchanging AF with saline in gastroschisis, intestinal damage can be prevented. Theoretically, induction of fetal diuresis with intraamniotic furosemide may increase AF volume and fetal swallowing rate, thus, increase absorption of AF by intestines; therefore, the clearance of meconium from the AF may increase. An experimental study was planned to investigate the effects of intraamniotic diuretic injection on the clearance of intraamniotic substances.

METHODS

Pregnant rabbits on the 23rd to 25th gestational day were divided into 2 groups as furosemide and control. Technetium tc99m labeled "tin colloid" was injected into the amniotic cavity, and AF sample was taken 10 minutes later. Furosemide was injected into the amniotic cavity afterwards. Two and 6 hours later, AF samples were obtained. Intestines were harvested at the end of the study. Control group received intraamniotic saline instead of furosemide. Radioactivities of the AF samples and intestines were determined by gamma counter. Clearance of the radioisotope from AF and intestinal accumulation were calculated.

RESULTS

The clearance of the radioisotope from AF was increased significantly in the furosemide group (n = 10) compared with the control group (n = 8; P <.01). Gastrointestinal accumulation of the radioisotope in the furosemide group was 4-fold higher than that the control group (P <.01).

CONCLUSIONS

Induction of fetal diuresis with intraamniotic furosemide accelerates the clearance of intraamniotic substances. This is probably caused by increased urinary output rate, which increases AF volume and consequently results in increased fetal swallowing of AF. In the diseases like gastroschisis and myelomeningocele, in which the contact with AF causes tissue damage, the elimination of meconium from AF in a somewhat natural manner like this method, should be studied further because it may be an alternative minimal invasive in utero treatment modality.

Esophageal ligature in experimental gastroschisis

BACKGROUND/PURPOSE

Recently, the authors have shown that in human fetuses suffering from gastroschisis, there is an amniotic fluid inflammatory response and that amniotic fluid exchange designed to disrupt the inflammatory loop seems to have a favorable impact on outcome. The authors, therefore, designed in the fetal sheep a model of gastroschisis in which amnioinfusion significantly improved the deleterious process. They hypothesized that regurgitation and presence of digestive enzyme in the amniotic fluid triggers and maintains the process of inflammation.

METHODS

To test this hypothesis, the authors used their model of gastroschisis in the fetal lamb combined with esophageal ligation and compared it with gastroschisis with or without amnioinfusion.

RESULTS

Of 34 fetuses operated on at midgestation (days 70 through 80), 11 died in utero or were stillborn, 8 had gastroschisis and amnioinfusion, 8 had gastroschisis and no amnioinfusion, and 7 had gastroschisis and esophageal ligation. There were 9 control fetuses. Fetuses were killed at day 145 by cesarean section. Extraabdominal bowels with fibrous peel were processed for histologic examination. Thickness of bowel muscularis (micrometers) was 82.7 +/- 19 for controls, 159 +/- 56 for the nonamnioinfused fetuses, 126 +/- 21 for the amnioinfused fetuses (P =.001), and 240 +/- 225.8 for fetuses with esophageal ligature combined with gastroschisis. The same results were obtained for thickness of serous fibrosis and plasma cell infiltration. Assay of amniotic fluid ferritin, lipase, and protein showed that only amnioinfusion lowered ferritin and protein to levels similar to those of controls, thus, illustrating its preventive effect on inflammation and that esophageal ligature did not prevent digestive enzyme presence in the amniotic fluid.

CONCLUSION

In this model of gastroschisis in the fetal sheep, ligature of the esophagus, which was supposed to protect the extruded bowel by preventing oral regurgitation of digestive enzymes and by creating a relative hydramnios, did not improve the inflammatory and deleterious process, which is best prevented by amnioinfusion.

Intestinal damage in gastroschisis correlates with the concentration of intraamniotic meconium

BACKGROUND/PURPOSE

Contact with amniotic fluid (AF) causes intestinal damage in gastroschisis, which has been shown to be caused by intraamniotic meconium. However, whether this intraamniotic meconium-induced intestinal damage is concentration dependent has not been investigated previously. The purpose of this study is to investigate the effects of intraamniotic human meconium at various concentrations on the intestines of chick embryo with gastroschisis.

METHODS

Five-day-old fertilized chick eggs were used. Gastroschisis was created through the amniotic cavity without opening the allantoic cavity. Sterile meconium was obtained from newborn humans. Meconium suspensions at various concentrations were prepared using saline and instilled into the amniotic cavity.

RESULTS

Intraamniotic 1:200 and 1:400 meconium was found to cause intestinal damage. Meconium concentrations lower than 1:400 did not cause intestinal damage. Histopathologic examination of the intestines of the 1:200 and 1:400 meconium groups showed serosal thickening, inflammation, focal fibrin, and collagen deposits. Histopathologic features of the intestines of the 1:600 and 1:800 meconium groups did not differ from the intestines of the control group.

CONCLUSION

Intraamniotic meconium, which is responsible for intestinal damage in gastroschisis, must reach a threshold level to induce intestinal damage. J Pediatr Surg 36:1811-1815.

The effect of amnio-allantoic fluid pH on the intestines: an experimental study in the chick embryo gastroschisis model

BACKGROUND/PURPOSE

Prolonged exposure to amniotic fluid causes the intestinal changes such as serosal edema, thickening, fibrous coating, and adhesions in gastroschisis. The effect of amnio-allantoic fluid (AAF) pH on intestines was evaluated using a chick embryo gastroschisis model.

METHODS

Seventy fertile eggs were divided into 5 groups: preliminary study (PS, n = 20), AAF control (AAC, n = 10), just gastroschisis (JG, n = 10), gastroschisis pretreated with placebo (GPP, n = 15), and gastroschisis pretreated with sodium bicarbonate (GPS, n = 15). The PS group was also divided into 2 subgroups to determine the biochemical differences between the amniotic and the allantoic fluid. Gastroschisis was created surgically at the 14th day of incubation. In GPS group, 8.4% NaHCO(3) solution (0.1 mL/100 mg/d) was instilled into the AAF for 4 days.

RESULTS

A significant decrease in intestinal damage was observed both macroscopically and microscopically in the group GPS compared with the JG and GPP groups.

CONCLUSIONS

Pretreatment with alkalization of AAF prevented intestinal damage because of gastroschisis. Alkalization could be a simple alternative for pretreatment with amniotic fluid exchange for human fetuses with gastroschisis.

Is vaginal delivery preferable to elective cesarean delivery in fetuses with a known ventral wall defect?

OBJECTIVE

We sought to test the hypothesis that vaginal delivery compared with elective cesarean delivery results in improved neonatal outcome in fetuses with a known isolated ventral wall defect.

STUDY DESIGN

We performed a retrospective chart review.

RESULTS

Between 1989 and 1999, we identified 102 infants with a confirmed antenatal diagnosis of an isolated ventral wall defect with either the diagnosis of an omphalocele or gastroschisis. Sixty-six infants were delivered by cesarean and 36 were delivered vaginally. There were no significant demographic differences between the study groups or between the two sites except that one center (Cincinnati) usually delivered these fetuses by cesarean whereas the other (Louisville) usually delivered such fetuses vaginally. Overall, there were a greater number of infants with gastroschisis than omphalocele (gastroschisis, n = 71; omphalocele, n = 31). After we controlled for primary versus staged closure of ventral wall defect and gestational age at delivery; the medians and interquartile ranges for cesarean and vaginal delivery were 39 (25, 63) days versus 42 (26, 75) days, respectively (P =.32), for neonatal length of stay and 13 (9, 18) days versus 13 (9, 26) days, respectively (P =.16), for days to enteral feeding. After we controlled for the size of the defect and the amount of bowel resected, the odds of primary closure given a vaginal delivery was about half that given a cesarean delivery (odds ratio, 0.56; 95% confidence interval, 0.18-1. 69), but this was not statistically significant. There was no statistically significant difference in the rates of neonatal death (2 [3%] vs 2 [6%]; P =.61) and neonatal sepsis (2 [3%] vs 4 [11%]; P =.18) for cesarean versus vaginal delivery. Maternal length of stay after delivery was found to be 1 day less after vaginal delivery [vaginal, 2 (2, 2) days; cesarean, 3 (2, 3) days; P =.0001]. There were 5 instances of maternal complications, and all 5 pregnancies were delivered by cesarean (P =.16).

CONCLUSION

Fetuses with an antenatal diagnosis of an isolated ventral wall defect may safely be delivered vaginally, and cesarean delivery should be performed for obstetric indications only.

The effects of intraamniotic human neonatal urine and meconium on the intestines of the chick embryo with gastroschisis

BACKGROUND/PURPOSE

Urinary waste products in the amniotic fluid has been implicated as a cause of intestinal damage (ID) in gastroschisis based on the fact that fetus urinates physiologically into the amniotic cavity. However, experimental and clinical data suggest that intrauterine defecation is a physiological event, thus gastrointestinal waste products also may be responsible for ID in gastroschisis. An experimental study was performed to investigate the effects of intraamniotic human neonatal urine and diluted meconium on the intestines of chick embryo with gastroschisis.

METHODS

Five-day-old fertilized chick eggs (Gallus domesticus) were used. Gastroschisis was created through amniotic cavity without opening the allantoic cavity. Sterile urine and meconium were obtained from newborn humans, and 1% meconium suspension was prepared. The eggs were divided in to 3 groups. In the first group, gastroschisis was created, and amniotic fluid was reinstilled without changing its composition (control group). Equal amounts of amniotic fluid and urine mixture was instilled into the amniotic cavity in second group (urine group) and 1% meconium suspension was instilled in similar fashion in the third group after creation of gastroschisis (meconium group).

RESULTS

Histopathologic features of the intestines of the urine group did not differ from the intestines of the control group. The meconium group's bowel showed serosal thickening, inflammation, focal fibrin, and collagen deposits. Histopathologic changes of intestines induced by intraamniotic diluted meconium are consistent with the ones described for human gastroschisis specimens.

CONCLUSION

Gastrointestinal waste products seem responsible for the ID in gastroschisis rather than urinary waste products.

Nitric oxide synthase inhibition prevents intestinal damage in gastroschisis: a morphological evaluation in chick embryos

PURPOSE

Increased small bowel nitric oxide (NO) synthase activity accused for postnatal intestinal dysmotility in gastroschisis. The purpose of this study is to evaluate the effect of prenatal NO synthase inhibition on intestinal damage in gastroschisis.

METHODS

Sixteen-day-old fertilized chick eggs were divided into 4 groups. In the control group, the allantoic and amniotic membranes were opened to create a common cavity. In the gastroschisis group, a defect in the abdominal wall was made, and intestinal loops were exteriorized. In the gastroschisis pretreated with L-NAME group, gastroschisis was created, and L-NAME was administered into the amnioallantoic cavity for 4 days. In the gastroschisis sham pretreated group, after the same surgical procedure as the previous group, same amount of saline was given beside L-NAME. At the end of 20th day of incubation, intestinal morphological changes were investigated macroscopically and microscopically.

RESULTS

Macroscopic changes such as shortening, thickening, and fibrous adhesions were found in the exteriorized bowels of the just gastroschisis group and the gastroschisis pretreated saline group. However, there was only mild thickening in the gastroschisis pretreated with L-NAME group. Microscopically, compared with the gastroschisis group, serosal thickness, muscular thickness, and bowel wall thickness were found to be significantly lower in the gastroschisis pretreated with L-NAME group (128.0 +/- 19.3 microm and 239.5 +/- 3.0 microm v 57.0 +/- 8.2 microm and 145.0 +/- 9.7 microm).

CONCLUSION

It is possible to decrease intrauterine intestinal morphological changes in gastroschisis by inhibiting NO synthase.

An experimental study investigating the effects of intraperitoneal human neonatal urine and meconium on rat intestines

Urinary waste products (UWP) in the amniotic fluid have been held responsible for the intestinal damage (ID) in gastroschisis, based on the fact that the fetus urinates physiologically into the amniotic cavity. However, experimental and clinical evidence suggests that intrauterine defecation is a physiological event; thus gastrointestinal waste products (GWP) may also be responsible for ID in gastroschisis. An experimental study was performed to investigate the effects of intraperitoneal human neonatal urine and diluted meconium on rat intestines. Adult Wistar albino rats were used. Sterile urine and meconium were obtained from newborn humans and 5% meconium suspension was prepared. Histopathological features of the intestines of the rats injected with urine did not differ from the intestines of the untreated rats. The bowel in rats injected with a meconium suspension showed serosal thickening, inflammation, focal fibrin and collagen deposits. Histopathological changes in intestines induced by intraperitoneal diluted meconium were consistent with those described for human gastroschisis specimens. We conclude that GWP, rather than UWP, seems to be responsible for the ID in gastroschisis.