Stem cells implanted with nanofibrous mats for injured endometrial regeneration and immune-microenvironment remodeling.

Severe endometrial injury caused by invasive uterine operation and/or endometritis often results in intrauterine adhesions (IUAs), which are named Asherman's syndrome (AS), further leading to menstrual disorders, infertility and severe complications during pregnancy and delivery. IUAs or AS has been a challenging medical problem. Stem cells are a promising therapeutic modality for endometrial regeneration in patients with refractory AS. Here, we developed a new system of adipose-derived mesenchymal stem cells (ADMSCs) implantation on silk fibroin/polycaprolactone (SF/PCL) electrospun nanofibers (ADMSCs-SF/PCL) and used it in the damaged endometrium of a rat model. After SF/PCL enhanced the proliferation of transplanted ADMSCs, the results showed that the ADMSCs-SF/PCL system could recover morphology, promote regeneration of the glands and angiogenesis by increasing CD31 expression, and reverse endometrial fibrosis by decreasing TGF-β/Smad expression. In addition, the ADMSCs-SF/PCL system also increased the expression of differentiation and decidualization markers, including HOXA11, HAND2 and FOXO1. Most importantly, the ADMSCs-SF/PCL system could remodel the special immune microenvironment, resulting in dominant NK infiltration and a normal Th1/Th2 bias in the endometrium. Moreover, this treatment had a lower but more persistent effect than estrogen. Thus, the ADMSCs-SF/PCL system enhanced endometrial restoration, suggesting a promising strategy for damaged endometrial regeneration and immune microenvironment remodeling.