Human amniotic membrane as newly identifed source of amniotic fuid pulmonary surfactant

Pulmonary surfactant (PS) reduces surface tension at the air-liquid interface in the alveolar epithelium of the lung, which is required for breathing and for the pulmonary maturity of the developing foetus. However, the origin of PS had never been thoroughly investigated, although it was assumed to be secreted from the foetal developing lung. Human amniotic membrane (hAM), particularly its epithelial cell layer, composes the amniotic sac enclosing the amniotic fuid. In this study, we therefore aimed to investigate a potential contribution of the cellular components of the hAM to pulmonary surfactant found in amniotic fuid. We identifed that cells within the native membrane contain lamellar bodies and express all four surfactant proteins as well as ABCA3. Lipidomic profling by nanoESI – MS/MS revealed the presence of the essential lipid species as found in PS. Also, the biophysical activity of conditioned cell culture supernatant obtained from hAM was tested with captive bubble surfactometry. hAM supernatant showed the ability to reduce surface tension, similar to human PS obtained from bronchoalveolar lavage. This means that hAM produces the essential PS-associated components and can therefore contribute as second potential source of PS in amniotic fuid aside from the foetal lung

Amnion: a versatile tissue and cell source in tissue repair and regeneration

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Mesenchymal Stem or Stromal Cells from Amnion and Umbilical Cord Tissue and Their Potential for Clinical Applications

Mesenchymal stem or stromal cells (MSC) have proven to offer great promise for cell-based therapies and tissue engineering applications, as these cells are capable of extensive self-renewal and display a multilineage differentiation potential. Furthermore, MSC were shown to exhibit immunomodulatory properties and display supportive functions through parakrine effects. Besides bone marrow (BM), still today the most common source of MSC, these cells were found to be present in a variety of postnatal and extraembryonic tissues and organs as well as in a large variety of fetal tissues. Over the last decade, the human umbilical cord and human amnion have been found to be a rich and valuable source of MSC that is bio-equivalent to BM-MSC. Since these tissues are discarded after birth, the cells are easily accessible without ethical concerns

Intact mitochondria migrate in membrane tubular network connections formed between human stem cells

The hypothesis of mitochondrial transfer between eukaryotic animal cells is intriguing, although its route of action and physiological role is unknown. Our goal was to examine intercellular connections among several types of stem cells and to observe whether intact functional mitochondria may travel via these connections. Time-lapse laser scanning confocal microscopy has shown that human amnion-derived stem cells as well as bone marrow derived mouse and human mesenchymal stem cells form cell-to-cell connections via a tubular membrane network. The maximal length of these micrometer-thick tubes is around 180 ?m. Interestingly, freshly isolated amniotic epithelial stem cells did not form these connections, only after several passages when the morphology of the cells is significantly altered. Large area cell-cell contacts can be retained as long thin membrane bridges after the cells depart and de novo tube formation is also observed. Using MitoTracker red staining we observed that intact mitochondria are moving in these tubes by 20 – 60 nm/s velocity, suggesting that mitochondria can leave one cell via the membrane tubes and can enter into another cell. These results suggest that specific types of stem cells form comprehensive tubular networks among each other. One physiological role of these networks may be that mitochondria can migrate from one cell to the other, which may be a novel way of communication among stem cells

Oxygen Tension Strongly Influences Metabolic Parameters and the Release of Interleukin-6 of Human Amniotic Mesenchymal Stromal Cells In Vitro

The human amniotic membrane (hAM) has been used for tissue regeneration for over a century. In vivo (in utero), cells of the hAM are exposed to low oxygen tension (1–4% oxygen), while the hAM is usually cultured in atmospheric, meaning high, oxygen tension (20% oxygen). We tested the influence of oxygen tensions on mitochondrial and inflammatory parameters of human amniotic mesenchymal stromal cells (hAMSCs). Freshly isolated hAMSCs were incubated for 4 days at 5% and 20% oxygen. We found 20% oxygen to strongly increase mitochondrial oxidative phosphorylation, especially in placental amniotic cells. Oxygen tension did not impact levels of reactive oxygen species (ROS); however, placental amniotic cells showed lower levels of ROS, independent of oxygen tension. In contrast, the release of nitric oxide was independent of the amniotic region but dependent on oxygen tension. Furthermore, IL-6 was significantly increased at 20% oxygen. To conclude, short-time cultivation at 20% oxygen of freshly isolated hAMSCs induced significant changes in mitochondrial function and release of IL-6. Depending on the therapeutic purpose, cultivation conditions of the cells should be chosen carefully for providing the best possible quality of cell therapy