3D Volumetric Mechanosensation of MCF7 Breast Cancer Spheroids in a Linear Stiffness Gradient GelAGE.

The tumor microenvironment presents spatiotemporal shifts in biomechanical properties with cancer progression. Hydrogel biomaterials like GelAGE offer the stiffness tuneability to recapitulate dynamic changes in tumor tissues by altering photo-energy exposures. Here, a tuneable hydrogel with spatiotemporal control of stiffness and mesh-network is developed. The volume of MCF7 spheroids encapsulated in a linear stiffness gradient demonstrates an inverse relationship with stiffness (p < 0.0001). As spheroids are exposed to increased crosslinking (stiffer) and greater mechanical confinement, spheroid stiffness increases. Protein expression (TRPV4, ß1 integrin, E-cadherin, and F-actin) decreases with increasing stiffness while showing strong correlations to spheroid volume (r2  > 0.9). To further investigate the role of volume, MCF7 spheroids are grown in a soft matrix for 5 days prior to a second polymerisation which presents a stiffness gradient to equally expanded spheroids. Despite being exposed to variable stiffness, these spheroids show even protein expression, confirming volume as a key regulator. Overall, this work showcases the versatility of GelAGE and demonstrates volume expansion as a key regulator of 3D mechanosensation in MCF7 breast cancer spheroids. This platform has the potential to further investigation into the role of stiffness and dimensionality in 3D spheroid culture for other types of cancers and diseases.

Living with Loss: study protocol for a randomized controlled trial evaluating an internet-based perinatal bereavement program for parents following stillbirth and neonatal death.

BACKGROUND: Stillbirth and neonatal death are devastating pregnancy outcomes with long-lasting psychosocial consequences for parents and families, and wide-ranging economic impacts on health systems and society. It is essential that parents and families have access to appropriate support, yet services are often limited. Internet-based programs may provide another option of psychosocial support for parents following the death of a baby. We aim to evaluate the efficacy and acceptability of a self-guided internet-based perinatal bereavement support program "Living with Loss" (LWL) in reducing psychological distress and improving the wellbeing of parents following stillbirth or neonatal death. METHODS: This trial is a two-arm parallel group randomized controlled trial comparing the intervention arm (LWL) with a care as usual control arm (CAU). We anticipate recruiting 150 women and men across Australia who have experienced a stillbirth or neonatal death in the past 2 years. Participants randomized to the LWL group will receive the six-module internet-based program over 8 weeks including automated email notifications and reminders. Baseline, post-intervention, and 3-month follow-up assessments will be conducted to assess primary and secondary outcomes for both arms. The primary outcome will be the change in Kessler Psychological Distress Scale (K10) scores from baseline to 3-month follow-up. Secondary outcomes include perinatal grief, anxiety, depression, quality of life, program satisfaction and acceptability, and cost-effectiveness. Analysis will use intention-to-treat linear mixed models to examine psychological distress symptom scores at 3-month follow-up. Subgroup analyses by severity of symptoms at baseline will be undertaken. DISCUSSION: The LWL program aims to provide an evidence-based accessible and flexible support option for bereaved parents following stillbirth or neonatal death. This may be particularly useful for parents and healthcare professionals residing in rural regions where services and supports are limited. This RCT seeks to provide evidence of the efficacy, acceptability, and cost-effectiveness of the LWL program and contribute to our understanding of the role digital services may play in addressing the gap in the availability of specific bereavement support resources for parents following the death of a baby, particularly for men. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, ACTRN12621000631808 . Registered prospectively on 27 May 2021.

Three-dimensional imaging of cell and extracellular matrix elasticity using quantitative micro-elastography.

Recent studies in mechanobiology have revealed the importance of cellular and extracellular mechanical properties in regulating cellular function in normal and disease states. Although it is established that cells should be investigated in a three-dimensional (3-D) environment, most techniques available to study mechanical properties on the microscopic scale are unable to do so. In this study, for the first time, we present volumetric images of cellular and extracellular elasticity in 3-D biomaterials using quantitative micro-elastography (QME). We achieve this by developing a novel strain estimation algorithm based on 3-D linear regression to improve QME system resolution. We show that QME can reveal elevated elasticity surrounding human adipose-derived stem cells (ASCs) embedded in soft hydrogels. We observe, for the first time in 3-D, further elevation of extracellular elasticity around ASCs with overexpressed TAZ; a mechanosensitive transcription factor which regulates cell volume. Our results demonstrate that QME has the potential to study the effects of extracellular mechanical properties on cellular functions in a 3-D micro-environment.

Optical coherence tomography-based contact indentation for diaphragm mechanics in a mouse model of transforming growth factor alpha induced lung disease.

This study tested the utility of optical coherence tomography (OCT)-based indentation to assess mechanical properties of respiratory tissues in disease. Using OCT-based indentation, the elastic modulus of mouse diaphragm was measured from changes in diaphragm thickness in response to an applied force provided by an indenter. We used a transgenic mouse model of chronic lung disease induced by the overexpression of transforming growth factor-alpha (TGF-α), established by the presence of pleural and peribronchial fibrosis and impaired lung mechanics determined by the forced oscillation technique and plethysmography. Diaphragm elastic modulus assessed by OCT-based indentation was reduced by TGF-α at both left and right lateral locations (p < 0.05). Diaphragm elastic modulus at left and right lateral locations were correlated within mice (r = 0.67, p < 0.01) suggesting that measurements were representative of tissue beyond the indenter field. Co-localised images of diaphragm after TGF-α overexpression revealed a layered fibrotic appearance. Maximum diaphragm force in conventional organ bath studies was also reduced by TGF-α overexpression (p < 0.01). Results show that OCT-based indentation provided clear delineation of diseased diaphragm, and together with organ bath assessment, provides new evidence suggesting that TGF-α overexpression produces impairment in diaphragm function and, therefore, an increase in the work of breathing in chronic lung disease.