P-804 Endometrial recovery via implantable CD133+ stem cells scaffold in Asherman’s syndrome therapy
Authors: Pardo Figuerez M , Venkatesan N , Fernandez E , Santamaría X , Simon C 
Published: June 2023

Abstract

Study question
Can we use CD133+ bone marrow derived stem cell (BMDSCs) loaded scaffolds to aid endometrial regeneration locally in Asherman syndrome (AS)?

Summary answer
Gelatin scaffolds supported transdifferentiation via decidualization of CD133+ BMDSCs. Implantable CD133+ scaffolds showed a certain degree of endometrial recovery in an AS rat model.

What is known already
We have demonstrated that CD133+ BMDSCs contribute to endometrial proliferation, and functional recovery in murine models of AS (Cervelló et al., 2015) and humans (Santamaria et al., 2016). This advanced cell therapy is already in Phase II Clinical trial regulated by EMA. Here, we use bioengineered loaded-cell scaffolds to obtain a more localized cell therapy.

Study design, size, duration
Gelatin scaffolds were prepared by cryogelation and analyzed by micro-computed tomography. For in vitro studies, CD133+ were cultured into the scaffolds and decidualized with 1 mM of 8-Bromoadenosine 3´5´-cyclic monophosphate sodium salt (cAMP) for 7 days. For studies in vivo, the scaffolds used as the control group (gelatin scaffold only) and the CD133+ loaded gelatin scaffolds were implanted into acid-damaged horns of rat AS induced model followed after one and three weeks.

Participants/materials, setting, methods
DNA quantification was carried out for cell viability on the scaffolds, whereas immunofluorescence, single cell RNA sequencing and RT-qPCR were used to assess decidualization. For studies in vivo, endometrial recovery was screened by scanning electron microscopy (SEM), hematoxylin and eosin staining (H&E) and RT-qPCR.

Main results and the role of chance
Cell spreading and proliferation was observed in gelatin loaded scaffolds due to its high pore size and similarity to the native extracellular matrix. IGFBP1 and Prolactin expression determined by immunofluorescence and RT-qPCR demonstrated that gelatin scaffold supported decidualization of CD133 into stromal decidual cells. Additionally, single cell data revealed a higher expression of stromal specific canonical markers (ENG, CXCL12, PDGFRB) and decidual associated genes (IRS2, COCH) in the decidualized scaffold. During the in vivo studies of the implanted scaffolds in a rat model of AS, we studied a set of inflammatory genes and paracrine secretory molecules. For the CD133+ loaded gelatin scaffold, we obtained a decrease in the expression of NF-kB (p ≤ 0.01). Additionally, the number of glands as well as endometrial thickness showed an increasing trend for the bioengineered cell loaded scaffolds after 3 weeks of implantation.

Limitations, reasons for caution
Endometrial functionality should be further analysed to needed full endometrial recovery.

Wider implications of the findings
Our bioengineered scaffolds mimic the native extracellular matrix, contributing to the viability, proliferation and decidualization of CD133+ BMDSCs. The herein implanted CD133+ BMDSCs scaffolds open new avenues to localized cell therapy for endometrial regeneration, especially for AS patients.

Trial registration number
Not applicable