Preterm premature rupture of membranes (PPROM) is a major cause of preterm birth and neonatal morbidity, with no established treatment to restore membrane integrity. Mese... More
Preterm premature rupture of membranes (PPROM) is a major cause of preterm birth and neonatal morbidity, with no established treatment to restore membrane integrity. Mesenchymal stem cells (MSCs), known for their regenerative and immunomodulatory properties, harbor promising therapeutic potential for fetal membranes repair. This study aimed to evaluate the rapid barrier reinforcement effect of Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) using in vitro and ex vivo models of PPROM. A wound healing assay was conducted to assess the effect of WJ-MSCs on human amniotic epithelial cells proliferation and migration. An ex vivo PPROM model was established using incised human fetal membranes to simulate membrane rupture. WJ-MSCs were directly applied to the lesion site at varying doses. Therapeutic efficacy was evaluated by a leak test and histological analysis. WJ-MSCs and their conditioned medium significantly enhanced epithelial wound closure in vitro, demonstrating that soluble paracrine factors secreted by WJ-MSCs have the potential to aid membrane injury restoration. In the ex vivo PPROM model, WJ-MSCs treatment reduced both leakage area and frequency of fetal membranes, with the most significant effect observed at a medium dose (5.0×105 cells). Histological evaluations revealed partial recovery of the fetal membranes, particularly the chorion layer. These findings suggest that WJ-MSCs contribute to rapid barrier reinforcement of injured fetal membranes. Taken together, WJ-MSCs enhance epithelial healing and support restoration of membrane integrity, highlighting their potential as a therapeutic approach for PPROM. Further, in vivo studies are required to confirm therapeutic efficacy and evaluate safety. Less
Autophagy, a type II programmed cell death, is essential for cell survival under stress, e.g. lung injury, and bone marrow-derived mesenchymal stem cells (BM-MSCs) have g... More
Autophagy, a type II programmed cell death, is essential for cell survival under stress, e.g. lung injury, and bone marrow-derived mesenchymal stem cells (BM-MSCs) have great potential for cell therapy. However, the mechanisms underlying the BM-MSC activation of autophagy to provide a therapeutic effect in ischaemia/reperfusion-induced lung injury (IRI) remain unclear. Thus, we investigate the activation of autophagy in IRI following transplantation with BM-MSCs. Seventy mice were pre-treated with BM-MSCs before they underwent lung IRI surgery in vivo. Human pulmonary micro-vascular endothelial cells (HPMVECs) were pre-conditioned with BM-MSCs by oxygen-glucose deprivation/reoxygenation (OGD) in vitro. Expression markers for autophagy and the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signalling pathway were analysed. In IRI-treated mice, administration of BM-MSCs significantly attenuated lung injury and inflammation, and increased the level of autophagy. In OGD-treated HPMVECs, co-culture with BM-MSCs attenuated endothelial permeability by decreasing the level of cell death and enhanced autophagic activation. Moreover, administration of BM-MSCs decreased the level of PI3K class I and p-Akt while the expression of PI3K class III was increased. Finally, BM-MSCs-induced autophagic activity was prevented using the inhibitor LY294002. Administration of BM-MSCs attenuated lung injury by improving the autophagy level via the PI3K/Akt signalling pathway. These findings provide further understanding of the mechanisms related to BM-MSCs and will help to develop new cell-based therapeutic strategies in lung injury. Less
Exposure to hyposmotic solution causes release of ATP from lens cells via hemichannels. Because hemichannel opening feasibly could swamp the cells with calcium, we carrie... More
Exposure to hyposmotic solution causes release of ATP from lens cells via hemichannels. Because hemichannel opening feasibly could swamp the cells with calcium, we carried out studies to measure the magnitude of the increase in cytoplasmic calcium concentration caused by hemichannel opening. In studies on porcine lens epithelial cells in primary culture, propidium iodide (PI) uptake was measured as an index of hemichannel opening. PI uptake was increased significantly in cells exposed to hyposmotic solution. The PI increase under hyposmotic conditions was suppressed by GAP 27, a connexin inhibitor peptide. In studies on cells loaded with Fura-2, continuous exposure to hyposmotic solution caused a cytoplasmic calcium concentration increase that peaked within ~30 sec then remained elevated at or below the peak response for more than 60 min. The peak calcium concentration was 186 ± 2.3 nM compared to a baseline value of 98.0 ± 1.4 nM. The calcium concentration increased a lot further in cells exposed to A23187 (2.5 µM) or the sodium-calcium exchange inhibitor SN-6 (10 µM) added after the onset of the calcium rise in hyposmotic solution. The cytoplasmic calcium increase in hyposmotic solution was abolished by GAP 27. Calcium returned to baseline in cells exposed to hyposmotic solution then treated with GAP 27 starting 2 min after the onset of the calcium rise. The calcium increase in hyposmotic solution did not occur when calcium was eliminated from the bathing medium. The responses to hyposmotic and hyperosmotic stress were different. There was no detectable increase in calcium or PI entry in cells exposed to hyperosmotic solution (500 mOsm). In summary, GAP 27-sensitive accumulation of PI by cultured lens epithelium points to connexin hemichannel opening and associated calcium entry. Even though connexins form channels with a large carrying capacity, calcium entry does not increase the cytoplasmic calcium concentration beyond a tolerable physiological range. Keywords: Calcium, connexin hemichannel, hyposmotic stress, lens epithelium, propidium iodide uptake Less
