Increased polymorphonuclear infiltration and iatrogenic amniotic band after closure of fetoscopic access sites with a bioactive membrane in the rabbit at midgestation

Biomaterial-based treatments for the prevention of preterm birth after iatrogenic rupture of the fetal membranes

Minimally invasive interventions to ameliorate or correct fetal abnormalities are becoming a clinical reality. However, the iatrogenic premature preterm rupture of the fetal membranes (FMs) (iPPROM), which may result in...

Why Do the Fetal Membranes Rupture Early after Fetoscopy? A Review

Iatrogenic preterm premature rupture of the fetal membranes (iPPROM) remains the Achilles' heel of keyhole fetal surgery (fetoscopy) despite significant efforts in preclinical models to develop new therapies. This limited success is partially due to incomplete understanding why the fetal membranes rupture early after fetoscopy and notable differences in membrane physiology between humans and domestic species. In this review, we summarize aspects of fetoscopy that may contribute to iPPROM, the previous efforts to develop new therapies, and limitations of preclinical models commonly used in fetal membrane research.

Application of Tissue Engineering and Regenerative Medicine in Prelabor Rupture of Membranes: a Review of the Current Evidence

Preterm prelabor rupture of membranes (PPROM) is the main cause of preterm delivery, resulting in increased perinatal morbidity and mortality. Several techniques have been studied for the healing of ruptured membranes, with some success. Before new techniques using tissue/organ engineering are applied in clinical practice, these techniques must be validated in clinical trials. To address this issue, the objective of this study was to summarize the current literature on interventions to seal or heal the amniotic membranes after PPROM. An electronic search was conducted using the keywords "fetal membranes," "premature rupture," "amnion," "tissue engineering," "fibrin tissue adhesive," "regenerative medicine," "tissue adhesive," "wound healing," and "fetoscopy" through the MEDLINE, Embase, and Cochrane CENTRAL databases, with the limitation of English-language studies. Through a review of the identified studies, it was found that spontaneous healing of the fetal membrane has not been successful. Several efforts have been made to seal membranes before or after rupture using different methods, including amniopatches, collagen, tissue patches, fibrin sealant, mussel-mimetic sealant, engineered cell matrix, and immunological supplements. However, most studies have been conducted in ex vivo or in vivo settings, so the safety and applicability of these techniques to spontaneous rupture of membranes in clinical settings have not been sufficiently tested. Overall, the current evidence is limited regarding the safety and effectiveness of interventions against PPROM.

Potential sealing and repair of human FM defects after trauma with peptide amphiphiles and Cx43 antisense

OBJECTIVE

We examined whether peptide amphiphiles functionalised with adhesive, migratory or regenerative sequences could be combined with amniotic fluid (AF) to form plugs that repair fetal membrane (FM) defects after trauma and co-culture with connexin 43 (Cx43) antisense.

METHODS

We assessed interactions between peptide amphiphiles and AF and examined the plugs in FM defects after trauma and co-culture with the Cx43antisense.

RESULTS

Confocal microscopy confirmed directed self-assembly of peptide amphiphiles with AF to form a plug within minutes, with good mechanical properties. SEM of the plug revealed a multi-layered, nanofibrous network that sealed the FM defect after trauma. Co-culture of the FM defect with Cx43 antisense and plug increased collagen levels but reduced GAG. Culture of the FM defect with peptide amphiphiles incorporating regenerative sequences for 5 days, increased F-actin and nuclear cell contraction, migration and polarization of collagen fibers across the FM defect when compared to control specimens with minimal repair.

CONCLUSIONS

Whilst the nanoarchitecture revealed promising conditions to seal iatrogenic FM defects, the peptide amphiphiles need to be designed to maximize repair mechanisms and promote structural compliance with high mechanical tolerance that maintains tissue remodeling with Cx43 antisense for future treatment.

Body wall defects and amniotic band syndrome in pig (Sus scrofa domesticus)

The amniotic band syndrome is a congenital condition. It is characterized by the presence of fibrous amniotic bands that may entangle or entrap different foetal parts in utero, resulting in deformation, malformation or disruption. We report on a female piglet presenting amniotic band adherences in the right abdominal flank, several body wall defects (gastroschisis, abdominoschisis with omphalocele), severe scoliosis, anomalous umbilical cord with single umbilical artery, anal atresia, anomalous liver and absent gall bladder, hypoplastic genitalia, ankylosis and arthrogryposis in pelvic limbs, and bilateral patellar agenesia. The ethiopatogenia is discussed, as well as the comparative and embryological implications.

Amnion-Analogous Medical Device for Fetal Membrane Healing: A Preclinical Long-Term Study

Although recent invasive fetal surgeries have improved fetal outcomes, fetal membrane rupture remains a major complication, leading to premature delivery, thus undermining the complete benefits of such procedures. A biocompatible amnion-analogous medical device (AMED) consisting of polycaprolactone framework and decellularized amniotic membrane (dAM)-derived hydrogel for restoration of amniotic membrane defect is developed using 3D printing technology. Its efficacy on healing iatrogenic fetal membrane defects in vitro is evaluated, showing that the dAM gel contains migratory and proliferative properties. The fetoscope feasibility of the developed AMED is assessed using a pregnant swine model. All animals had successfully recovered from anesthesia and the fetoscopic procedure and maintained a healthy condition until the end of the pregnancy. AMED exhibits superior surgical handling characteristics and is easy to manufacture, nonimmunogenic, biocompatible, and suitable for storage and transport for off-the-shelf use; hence, it can be used in successfully sealing defect sites, thus improving the preservation of the amniotic fluid, which in turn improves fetal survival and development.

Tissuepatch is biocompatible and seals iatrogenic membrane defects in a rabbit model

OBJECTIVE

To evaluate novel sealing techniques for their biocompatibility and sealing capacity of iatrogenic fetal membrane defects in a pregnant rabbit model.

METHOD

At day 23 of gestation (term = d31), a standardized fetoscopy was performed through a 14G cannula. The resulting fetal membrane defect was closed with condensed collagen, collagen with fibrinogen, Tissuepatch, Duraseal, or a conventional collagen plug (Lyostypt) as reference. At d30, the fetuses were harvested and full thickness fetal membrane samples were analyzed. The study consisted of 2 consecutive parts: (1) biocompatibility testing by fetal survival, apoptosis, and infiltration of polymorphonuclear cells in the membranes and (2) the efficacy to seal fetal membrane defects.

RESULTS

Three sealants (collagen with fibrinogen, Duraseal, or Lyostypt) were associated with a higher fetal mortality compared to control unmanipulated littermates and hence were excluded from further analysis. Tissuepatch was biocompatible, and amniotic fluid levels were comparable to those of control untouched littermates. Compared to the condensed collagen, Tissuepatch was also easier in surgical handling and induced limited cell proliferation.

CONCLUSION

Tissuepatch had the best biocompatibility and efficacy in sealing an iatrogenic fetal membrane defect in the pregnant rabbit compared to other readily available sealants.

Engineered cell instructive matrices for fetal membrane healing

Iatrogenic preterm prelabour rupture of fetal membranes (iPPROM) occurs in 6-45% of the cases after fetoscopic procedures, posing a significant threat to fetal survival and well-being. The number of diagnostic and therapeutic prenatal interventions available is increasing, thus developing treatment options for iPPROM is becoming more important than ever before. Fetal membranes exhibit very restricted regeneration and little is known about factors which might modulate their healing potential, rendering various materials and strategies to seal or heal fetal membranes pursued over the past decades relatively fruitless. Additionally, biocompatible materials with tunable in vivo stability and mechanical and biological properties have not been available. Using poly(ethylene glycol)-based biomimetic matrices, we provide evidence that, upon presentation of appropriate biological cues in three dimensions, mesenchymal progenitor cells from the amnion can be mobilized, induced to proliferate and supported in maintaining their native extracellular matrix production, thus creating a suitable environment for healing to take place. These data suggest that engineering materials with defined mechanical and biochemical properties and the ability to present migration- and proliferation-inducing factors, such as platelet-derived growth factor, basic fibroblast growth factor or epidermal growth factor, could be key in resolving the clinical problem of iPPROM and allowing the field of fetal surgery to move forward.

Amniopatch for iatrogenic rupture of the fetal membranes

With the increased use of invasive fetal procedures, the number of women facing post-procedure membrane rupture is increasing. Here we review the use of platelets and fresh frozen plasma for sealing iatrogenic fetal membrane defects by describing the mechanisms of action of the amniopatch procedure as well as published experience. In cases of iatrogenic preterm pre-labour rupture of the membranes, amniopatch effectively seals the fetal membranes in over two-thirds of cases. There is a risk of 16% of in utero fetal death, which may occur at varying intervals from the procedure and often for unknown reasons. Amniopatch has also been used as a treatment of chorionic membrane separation. In summary, current experience suggests that in cases of early onset but persistent amniotic fluid leakage following an invasive fetal procedure, amniopatch is an option.

[Amniopatch to treat iatrogenic rupture of the fetal membranes]

OBJECTIVE

With the increased use of invasive fetal procedures, the number of patients facing postprocedure membrane rupture is increasing. We aimed to describe the use of platelets and fresh frozen plasma for sealing iatrogenic fetal membrane defects.

PATIENTS AND METHODS

We describe the mechanisms of action of the amniopatch procedure as well as published experience.

RESULTS

Amniopatch effectively sealed the fetal membranes in over two thirds of published cases (n=44). There is a risk of 17% of in utero fetal death, which may occur remotely from the procedure and is often unexplained.

DISCUSSION AND CONCLUSION

In case of early onset but persistent amniotic fluid leakage following an invasive fetal procedure, amniopatch may be offered.

Enrichment of collagen plugs with platelets and amniotic fluid cells increases cell proliferation in sealed iatrogenic membrane defects in the foetal rabbit model

OBJECTIVES

The purpose of this study was to evaluate cell proliferation in platelet-enriched collagen plugs with and without addition of amniotic fluid-derived heterologous foetal cells to seal an iatrogenic membrane defect in the foetal rabbit model.

METHODS

Amniotic fluid cells were harvested from three donor does at 23 days of gestation (term = 32 days) and labelled with carboxyfluorescein diacetate succinimidyl ester (CFDA-SE). In 42 other does, foetal membrane defects were induced by foetoscopic needle puncture at 23 days of gestation, and closed with either a platelet-enriched collagen plug with (n = 44) or without (n = 32) amniotic fluid cells. At 30 days of gestation, the defects were harvested and assessed microscopically.

RESULTS

The plugs enriched with heterologous amniotic fluid cells more commonly had proliferating cells in the centre of the plug than those without cell addition. CFDA-SE labelling confirmed the presence of heterologous amniotic fluid cells over the entire membrane plug. Cell typing showed a mixture of fibroblasts and epithelial cells at the wound edges, whereas in the centre, there was an abundance of fibroblasts.

CONCLUSION

When sealing iatrogenic membrane defects in the foetal rabbit model, enrichment of collagen plugs with platelets and amniotic fluid-derived heterologous foetal cells increases local cell proliferation.

Enhancing sealing of fetal membrane defects using tissue engineered native amniotic scaffolds in the rabbit model

OBJECTIVE

The purpose of this study was to compare the efficacy of native engineered amniotic scaffolds (AS) and polyesterurethane scaffolds (DegraPol) and document wound healing response when sealing iatrogenic fetal membrane defects in the rabbit model.

STUDY DESIGN

Native AS were engineered from freshly harvested membranes of 23 days' gestational age (GA; term = 31-2 d). Acellularity of AS was assessed by histology, light and scanning electron microscopy. Fetal membrane defects were created by 14 gauge-needle puncture at GA 23 days and primarily closed with AS (n = 10) or DegraPol (n = 10) or left unclosed (positive controls; n = 10). Sixty-one sacs served as negative controls. At GA 30 days a second look hysterotomy was performed to assess presence of amniotic fluid (AF) and harvest plugging sites for microscopic evaluation.

RESULTS

Engineered AS had a cell-free collagenous fiber network. AF was significantly higher only in the DegraPol group (78%; P < .05) compared to the AF in positive controls (17%). Integration of plugs in the fetal membrane defect was better with AS than DegraPol, with higher reepithelialization rates (AS: 52.5% +/- 6.5%; DegraPol: 11.6% +/- 2.6%; P < .001) and proliferation indices (AS: 0.47 +/- 0.03; DegraPol: 0.28 +/- 0.04; P = .001). In both treatment groups, cell proliferation in the myometrium was increased (P < .05).

CONCLUSION

Native AS seal iatrogenic fetal membrane defects better than DegraPol. Within a week, there is abundant reepithelilization and minimal local inflammation. This yields the proof of principle that engineered native, amniotic membrane scaffolds enhance fetal membrane wound healing response.

Fetal membrane healing after spontaneous and iatrogenic membrane rupture: a review of current evidence

In view of the important protective role of the fetal membranes, wound sealing, tissue regeneration, or wound healing could be life saving in cases of preterm premature rupture of the membranes. Although many investigators are studying the causes of preterm premature rupture of membranes, the emphasis has not been on the wound healing capacity of the fetal membranes. In this review, the relevant literature on the pathophysiologic condition that leads to preterm premature rupture of membranes will be summarized to emphasize a continuum of events between rupture and repair. We will present the current knowledge on fetal membrane wound healing and discuss the clinical implications of these findings. We will critically discuss recent experimental interventions in women to seal or heal the fetal membranes after preterm premature rupture of membranes.

A histological study of fetoscopic membrane defects to document membrane healing

OBJECTIVE

To evaluate the rate of spontaneous healing in human fetal membranes after fetoscopy.

STUDY DESIGN

Membranes from patients that had undergone fetoscopic interventions and delivered in one of the two treatment centers were included in the study. The membranes were examined macroscopically for any remaining defects and if present, the size of the defect in chorion and amnion was measured. Subsequently, the defect was excised and stained with HE for histological evaluation. Additional immunohistochemical staining was performed with Ki-67, cytokeratin and vimentin. The proliferation index (percentage of proliferating cells) was calculated in amnion and chorion.

RESULTS

Nineteen membrane defects were included in the study. The median time interval between invasive procedures and delivery was 60 days (range 3-112). All fetoscopic defects (n=19) could be identified in the gestational sac and in none spontaneous closure had occurred. Proliferation indices as measured by inmunohistochemistry were very low (median 2.8%, range 0-7%) in the chorion and 0% in the amnion.

CONCLUSION

No evidence of spontaneous membrane healing was found after fetoscopic procedures, suggesting that the membrane defect normally persists until delivery. Absence of amniotic fluid leakage after invasive procedures may be based on mechanisms other than histologic membrane repair.