Thin endometrium is a primary cause of failed embryo transfer, resulting in long‐term infertility and negative family outcomes. While hormonal treatments have greatly improved fertility results for some women, these responses remain unsatisfactory due to damage and infection of the complex endometrial microenvironment. In this study, a multifunctional microenvironment‐protected exosome‐hydrogel is designed for facilitating endometrial regeneration and fertility restoration via in situ microinjection and endometrial regeneration. This exosome hydrogel is formulated via Ag+‐S dynamic coordination and fusion with adipose stem cell‐derived exosomes (ADSC‐exo), yielding an injectable preparation that is sufficient to mitigate infection risk while also possessing the antigenic contents and paracrine signaling activity of the ADSC source cells, enabling regeneration of the endometrial microenvironment. In vitro, this exosome‐hydrogel exerts an outstanding neovascularization‐promoting effect, increased human umbilical vein endothelial cell proliferation and tube formation for 1.87 and 2.2 folds. In vivo, microenvironment‐protected exosome‐hydrogel also reveals to promote neovascularization and tissue regeneration while suppressing local tissue fibrosis. Importantly, regenerated endometrial tissue is more receptive to give embryos and birth to a healthy newborn. This microenvironment‐protected exosome‐hydrogel system offers a convenient, safe, and noninvasive approach for repairing thin endometrium and fertility restoration.

This work was supported by grants from the National Natural Science Foundation of China (NSFC) (31770989 to Y.W.) and the Shanghai Ninth People's Hospital Foundation of China (JYLJ030 to Y.W.). None of the authors have any conflicts of interest to declare.

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Pig epiblast-derived pluripotent stem cells are considered to have great potential and broad prospects for human therapeutic model development and livestock breeding. Despite ongoing attempts since the 1990s, no stably defined pig epiblast-derived stem cell line has been established. Here, guided by insights from a large-scale single-cell transcriptome analysis of pig embryos from embryonic day (E) 0 to E14, specifically, the tracing of pluripotency changes during epiblast development, we developed an in vitro culture medium for establishing and maintaining stable pluripotent stem cell lines from pig E10 pregastrulation epiblasts (pgEpiSCs). Enabled by chemical inhibition of WNT-related signaling in combination with growth factors in the FGF/ERK, JAK/STAT3, and Activin/Nodal pathways, pgEpiSCs maintain their pluripotency transcriptome features, similar to those of E10 epiblast cells, and normal karyotypes after more than 240 passages and have the potential to differentiate into three germ layers. Strikingly, ultradeep in situ Hi-C analysis revealed functional impacts of chromatin 3D-spatial associations on the transcriptional regulation of pluripotency marker genes in pgEpiSCs. In practice, we confirmed that pgEpiSCs readily tolerate at least three rounds of successive gene editing and generated cloned gene-edited live piglets. Our findings deliver on the long-anticipated promise of pig pluripotent stem cells and open new avenues for biological research, animal husbandry, and regenerative biomedicine.