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Peripheral nerve fibrosis and painful adhesions are common, recurring pathological sequelae following injury. In this study, vital human amnion (hAM), an increasingly interesting biomaterial for regenerative medicine, was investigated as a novel therapy. hAM was first analyzed in vitro regarding its anti-adhesive characteristics. Then, the reflected region of hAM which was identified as more suitable, was transplanted into female Sprague Dawley rats with recurring sciatic nerve scarring (n = 24) and compared with untreated controls (n = 30) at one, four and twelve weeks. Immune response and fibrosis were investigated by (immuno)histochemical analysis. Nerve structure was examined and function determined using electrophysiology and gait analysis. Here we identified strongly reduced adhesions in the hAM-treated rats, displaying a significant difference at four weeks post transplantation compared to untreated controls (p = .0052). This correlated with the in vitro cell attachment test on hAM explants, which demonstrated a distinctly limited ability of fibroblasts to adhere to amniotic epithelial cells. Upon hAM transplantation, significantly less intraneural fibrosis was identified at the later time points. Moreover, hAM-treated rats exhibited a significantly higher sciatic functional index (SFI) after four weeks compared to controls (p .05), which indicated a potentially pro-regenerative effect of hAM. As a possible explanation, an impact of hAM on the endogenous immune response, including T cell and macrophage subsets, was indicated. We conclude that hAM is strongly effective against recurring nerve scarring and induces an anti-fibrotic and pro-regenerative effect, making it highly promising for treating adhesion-related disorders.Abnormal fibrotic bonding of tissues, frequently involving peripheral nerves, affects millions of people worldwide. These so-called adhesions usually cause severe pain and drastically reduce quality of life. To date, no adequate treatment exists and none is routinely used in the clinical practice. In this study, vital human amnion, the innermost of the fetal membranes, was transplanted in a rat model of peripheral nerve scarring and recurring adhesions as novel therapeutic approach. Amniotic cells have already demonstrated to feature stem-cell like properties and produce pro-regenerative factors, which makes the amnion an increasingly promising biomaterial for regenerative medicine. We identified that its transplantation was very effective against peripheral nerve scarring and distinctly reduced recurring adhesions. Moreover, we identified a pro-regenerative effect. This study showed that the amnion is a highly promising novel therapeutic approach for adhesion-related disorders.

Background aims Lipedema is a hormone-related disease of women characterized by enlargement of the extremities caused by subcutaneous deposition of adipose tissue. In healthy patients application of autologous adipose tissue–derived cells has shown great potential in several clinical studies for engrafting of soft tissue reconstruction in recent decades. The majority of these studies have used the stromal vascular fraction (SVF), a heterogeneous cell population containing adipose-derived stromal/stem cells (ASC), among others. Because cell identity and regenerative properties might be affected by the health condition of patients, we characterized the SVF cells of 30 lipedema patients in comparison to 22 healthy patients. Methods SVF cells were analyzed regarding cell yield, viability, adenosine triphosphate content, colony forming units and proliferative capacity, as well as surface marker profile and differentiation potential in vitro. Results Our results demonstrated a significantly enhanced SVF cell yield isolated from lipedema compared with healthy patients. In contrast, the adipogenic differentiation potential of SVF cells isolated from lipedema patients was significantly reduced compared with healthy patients. Interestingly, expression of the mesenchymal marker CD90 and the endothelial/pericytic marker CD146 was significantly enhanced when isolated from lipedema patients. Discussion The enhanced number of CD90+ and CD146+ cells could explain the increased cell yield because the other tested surface marker were not reduced in lipedema patients. Because the cellular mechanism and composition in lipedema is largely unknown, our findings might contribute to a better understanding of its etiology.

Cells of the human amniotic membrane (hAM) have stem cell characteristics with low immunogenicity and anti-inflammatory properties. While hAM is an excellent source for tissue engineering, so far, its sub-regions have not been taken into account. We show that placental and reflected hAM differ distinctly in morphology and functional activity, as the placental region has significantly higher mitochondrial activity, however significantly less reactive oxygen species. Since mitochondria may participate in processes such as cell rescue, we speculate that amniotic sub-regions may have different potential for tissue regeneration, which may be crucial for clinical applications.

Amniotic membrane is a highly promising cell source for tissue engineering. Being part of the placenta, this tissue is abundantly available. It can be processed easily to yield large amounts of epithelial and mesenchymal cells that have shown broad differentiation potential. For tissue-engineering purposes, cells may be applied either directly after isolation from the tissue or after a period of in vitro expansion to obtain higher cell numbers. In order to investigate the advantages and drawbacks of these strategies we compared freshly isolated and cultivated human amniotic epithelial cells (hAEC) regarding their surface antigen (Ag) expression profile and osteogenic differentiation capacity.Expression of surface Ag that are characteristic for mesenchymal stromal and embryonic stem cells was analyzed by flow cytometry. Different protocols for osteogenic and adipogenic differentiation were compared.We have demonstrated that expression of surface Ag changes dramatically during cultivation of hAEC. While not or only weakly expressed on primary isolates, the mesenchymal markers CD13, CD44, CD49e, CD54, CD90 and CD105 are strongly up-regulated during in vitro propagation. In contrast, expression of the embryonic markers TRA-1-60 and TRA-1-81, but not SSEA-4, rapidly decreases upon cultivation. This phenotypic shift is associated with a reduction in osteogenic differentiation.Our results suggest that phenotypic alterations of hAEC during in vitro cultivation might be responsible for a functional reduction of the differentiation potential, which has to be considered for the potential application of these cells in regenerative medicine.