Perchiazzi, G. | Search bioRxiv

bioRxiv2026

Exploring Ventilator-Induced Lung Injury: A Comprehensive Ex-Vivo Study Using Phase-Contrast MicroCT and Atomic Force Microscopy

Mechanical ventilation (MV) can induce or exacerbate ventilator-induced lung injury (VILI), particularly in mechanically heterogeneous lungs with pre-existing injury. We investigated VILI in a rat model of bleomycin-induced lung injury and compared it with healthy controls using a combined in-vivo and ex-vivo imaging approach. Previously acquired in-vivo data from four-dimensional (4D) phase-contrast synchrotron micro-computed tomography (microCT) and forced oscillation measurements showed increased lung elastance and reduced local acinar strain in bleomycin-induced injured lungs at baseline and after injurious MV. To identify structural and mechanical correlates, we performed automated three-dimensional (3D) pore analysis and atomic force microscopy (AFM) on formalin-fixed, paraffin-embedded lung tissue, complemented by histology and spatial co-registration. Ex-vivo analysis revealed pronounced airspace enlargement after injurious MV of healthy lungs, whereas this effect was attenuated in fibrotic lungs. AFM demonstrated region-specific mechanical responses, and correlation analyses linked pore geometry and nanoscale stiffness to in-vivo lung mechanics. Spatial analysis further showed colocalization of VILI-associated airspace damage with injured regions. Overall, extracellular matrix remodelling modifies the lungs mechanical response to injurious MV. This multiscale correlative approach provides mechanistic insight into the interplay between lung injury and VILI and informs ventilation strategies in structurally altered lungs.

pathology↗

bioRxiv2023

Fluid restrictive resuscitation with high molecular weight hyaluronan infusion in early peritonitis-sepsis

Sepsis is a condition with high morbidity and mortality. Prompt recognition and initiation of treatment is essential. Despite forming an integral part of sepsis management, fluid resuscitation may also lead to volume overload, which in turn is associated with increased mortality. The optimal fluid strategy in sepsis resuscitation is yet to be defined. Hyaluronan, an endogenous glycosaminoglycan with high affinity to water is an important constituent of the endothelial glycocalyx. We hypothesized that exogenously administered hyaluronan would contribute to endothelial glycocalyx integrity and counteract intravascular volume depletion in a fluid restrictive model of peritonitis. In a prospective, blinded model of porcine peritonitis-sepsis, we randomized animals to intervention with hyaluronan (n=8) or 0.9% saline (n=8). The animals received an infusion of 0.1% hyaluronan 6 ml/kg/h, or the same volume of saline, during the first two hours of peritonitis. Stroke volume variation and hemoconcentration were comparable in the two groups throughout the experiment. Cardiac output (p=0.008 and p=0.017) and diastolic blood pressure (p=0.015 and p=0.019) were higher in the intervention group during the infusion of hyaluronan, but these effects disappeared as the experiment proceeded. The increase in lactate was more pronounced in the intervention group (p=0.041) throughout the experiment, while concentrations of surrogate markers of glycocalyx damage; syndecan 1 (0.6 {+/-} 0.2 ng/ml vs 0.5 {+/-} 0.2 ng/ml, p=0.292), heparan sulphate (1.23 {+/-} 0.2 vs 1.4 {+/-} 0.3 ng/ml, p=0.211) and vascular adhesion protein 1 (7.0 {+/-} 4.1 vs 8.2 {+/-} 2.3 ng/ml, p=0.492) were comparable in the two groups at the end of the experiment. In conclusion, hyaluronan did not counteract intravascular volume depletion in early peritonitis sepsis. The intervention was associated with higher cardiac output and diastolic blood pressure, than placebo, during the infusion. However, the increase in lactate throughout the experiment was more pronounced in the intervention group.

pharmacology and toxicology↗