Mechanical forces in fetal lung development: opportunities for translational research

Impact of fetal treatments for congenital diaphragmatic hernia on lung development

The extent of lung hypoplasia impacts the survival and severity of morbidities associated with congenital diaphragmatic hernia (CDH). The alveoli of CDH infants and in experimental models of CDH have thickened septa with fewer type II pneumocytes and capillaries. Fetal treatments of CDH-risk preterm birth. Therefore, treatments must aim to balance the need for increased gas exchange surface area with the restoration of pulmonary epithelial type II cells and the long-term respiratory and neurodevelopmental consequences of prematurity. Achievement of sufficient lung development in utero for successful postnatal transition requires adequate intra-thoracic space for lung growth, maintenance of sufficient volume and appropriate composition of fetal lung fluid, regular fetal breathing movements, appropriate gas exchange area, and ample surfactant production. The review aims to examine the rationale for current and future therapeutic strategies to improve postnatal outcomes of infants with CDH.

Apnoea of Prematurity and Neurodevelopmental Outcomes: Current Understanding and Future Prospects for Research

Infants who are born prematurely are at significant risk of apnoea. In addition to the short-term consequences such as hypoxia, apnoea of prematurity has been associated with long-term morbidity, including poor neurodevelopmental outcomes. Clinical trials have illustrated the importance of methylxanthine drugs, in particular caffeine, in reducing the risk of long term adverse neurodevelopmental outcomes. However, the extent to which apnoea is causative of this secondary neurodevelopmental delay or is just associated in a background of other sequelae of prematurity remains unclear. In this review, we first discuss the pathophysiology of apnoea of prematurity, previous studies investigating the relationship between apnoea and neurodevelopmental delay, and treatment of apnoea with caffeine therapy. We propose a need for better methods of measuring apnoea, along with improved understanding of the neonatal brain's response to consequent hypoxia. Only then can we start to disentangle the effects of apnoea on neurodevelopment in preterm infants. Moreover, by better identifying those infants who are at risk of apnoea, and neurodevelopmental delay, we can work toward a risk stratification system for these infants that is clinically actionable, for example, with doses of caffeine tailored to the individual. Optimising treatment of apnoea for individual infants will improve neonatal care and long-term outcomes for this population.

The characteristics of Ishikawa endometrial cancer cells are modified by substrate topography with cell-like features and the polymer surface

Conventional in vitro culture studies on flat surfaces do not reproduce tissue environments, which have inherent topographical mechanical signals. To understand the impact of these mechanical signals better, we use a cell imprinting technique to replicate cell features onto hard polymer culture surfaces as an alternative platform for investigating biomechanical effects on cells; the high-resolution replication of cells offers the micro- and nanotopography experienced in typical cell–cell interactions. We call this platform a Bioimprint. Cells of an endometrial adenocarcinoma cell line, Ishikawa, were cultured on a bioimprinted substrate, in which Ishikawa cells were replicated on polymethacrylate (pMA) and polystyrene (pST), and compared to cells cultured on flat surfaces. Characteristics of cells, incorporating morphology and cell responses, including expression of adhesion-associated molecules and cell proliferation, were studied. In this project, we fabricated two different topographies for the cells to grow on: a negative imprint that creates cell-shaped hollows and a positive imprint that recreates the raised surface topography of a cell layer. We used two different substrate materials, pMA and pST. We observed that cells on imprinted substrates of both polymers, compared to cells on flat surfaces, exhibited higher expression of β1-integrin, focal adhesion kinase, and cytokeratin-18. Compared to cells on flat surfaces, cells were larger on imprinted pMA and more in number, whereas on pST-imprinted surfaces, cells were smaller and fewer than those on a flat pST surface. This method, which provided substrates in vitro with cell-like features, enabled the study of effects of topographies that are similar to those experienced by cells in vivo. The observations establish that such a physical environment has an effect on cancer cell behavior independent of the characteristics of the substrate. The results support the concept that the physical topography of a cell’s environment may modulate crucial oncological signaling pathways; this suggests the possibility of cancer therapies that target pathways associated with the response to mechanical stimuli.