Mammalian target of rapamycin inhibitors have shown promising results in the management of kaposiform hemangioendothelioma (KHE). The purpose of this study was to present our experience involving sirolimus therapy for KHE. A retrospective study was conducted to review the medical documents of 26 patients with KHE who were treated with sirolimus at our hospital between March 2012 and December 2016. Fifteen males and 11 females manifested KHE in infancy with an average age of 2.9 ± 1.8 months. Multiple anatomical sites were involved. Four patients had multifocal lesions, while 22 patients had solitary lesions. Twenty‐five patients had Kasabach–Merritt phenomenon (KMP). Twenty patients completed sirolimus therapy in 28.3 ± 12.5 months. Nineteen KHE lesions reduced to small residuals with platelet counts reaching normal levels 3.7 ± 2.8 weeks after treatment; one KHE lesion had no response to therapy. One patient with multifocal lesions died due to a severe infection, although the patient had previously responded to sirolimus. Five patients remained in treatment and had good responses with normal platelet counts. Nineteen patients with anemia had normal hemoglobin levels after 3.5 ± 1.9 weeks of treatment. Mild side effects were observed. The median follow‐up time was 32 months (26–60 months), with no evidence of recurrences. Sirolimus was shown to be efficacious in the management of KHE with an average course of 28 months. The time‐to‐response was variable, with an average of 1 week. After 4 weeks of treatment, the platelet count and hemoglobin level had normalized. Multifocal KHE with KMP is more severe than solitary KHE.

Derivation of bona fide porcine pluripotent stem cells is still a critical issue because porcine embryonic stem cells (ESCs) are not available yet, and most of the culture conditions to maintain porcine induced pluripotent stem cells (piPSCs) are based on conditions for mouse and human iPS cells. In this study, we generated a doxycycline-inducible porcine iPS cell line (DOX-iPSCs) and used it to screen the optimal culture condition to sustain the self-renewal of piPSCs. We found that LIF and b-FGF were required for porcine cell reprogramming, but were not essential cytokines for maintaining the self-renewal and pluripotency of piPSCs. A serum-free 3i medium, which includes three inhibitors CHIR99021, SB431542, and PD0325901, three cytokines BMP4, SCF, and IL-6, and human platelet lysates (PL), was made through serious selections. In 3i condition, the doxycycline-inducible iPSCs could be passaged for a long term without the addition of doxycycline, and the flattened morphology of intermediate state piPSCs could convert to the naïve-like morphology with the increase in endogenous pluripotent gene expressions. Additionally, pPSC cell line isolated from 5.5 days blastocysts could be sustained in 3i medium and the expression of endogenous pluripotent genes OCT4, ESRRB, and STELLA was significantly increased. Our finding directed a new reprogramming strategy by using 3i condition to maintain and convert primed piPSCs into naïve-like pluripotent state. A combination of traditional LIF/b-FGF conditions and 3i condition may help us to find out an appropriate reprogramming approach to generate the naïve state of porcine iPSCs.

Reported pig induced pluripotent stem cells (piPSCs) have shown either a bFGF-dependent state with human embryonic stem cell (ESC) and mouse epiblast stem cell (EpiSC) morphology and molecular features or piPSCs exist in a LIF-dependent state and resemble fully reprogrammed mouse iPSCs. The features of authentic piPSCs and molecular events during the reprogramming are largely unknown. In this study, we assessed the transcriptome profile of multiple piPSC lines derived from different laboratories worldwide and compared to mouse and human iPSCs to determine the molecular signaling pathways that might play a central role in authentic piPSCs. The results demonstrated that the up-regulation of endogenous epithelial cells adhesion molecule (EpCAM) was correlated with the pluripotent state of pig pluripotent cells, which could be utilized as a marker for evaluating pig cell reprogramming. Comparison of key signaling pathways JAK-STAT, NOTCH, TGFB1, WNT and VEGF in pig, mouse and human iPSCs showed that the core transcriptional network to maintain pluripotency and self-renewal in pig were different from that in mouse, but had significant similarities to human. Pig iPSCs, which lacked expression of specific naïve state markers KLF2/4/5 and TBX3, but expressed the primed state markers of Otx2 and Fabp7, share defining features with human ESCs and mouse EpiSCs. The cluster of imprinted genes delineated by the delta-like homolog 1 gene and the type III iodothyronine deiodinase gene (DLK1-DIO3) were silenced in piPSCs as previously seen in mouse iPSCs that have limited ability to contribute to chimaeras. These key differences in naïve state gene and imprinting gene expression suggests that so far known piPSC lines may be more similar to primed state cells. The primed state of these cells may potentially explain the rare ability of piPSCS to generate chimeras and cloned offspring.

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