An adaptable research platform for ex vivo normothermic machine perfusion of the liver.

PURPOSE: This paper presents an assessment of a low-cost organ perfusion machine designed for use in research settings. The machine is modular and versatile in nature, built on a robotic operating system (ROS2) pipeline allowing for the addition of specific sensors for different research applications. Here we present the system and the development stages to achieve viability of the perfused organ. METHODS: The machine's perfusion efficacy was assessed by monitoring the distribution of perfusate in livers using methylene blue dye. Functionality was evaluated by measuring bile production after 90 min of normothermic perfusion, while viability was examined using aspartate transaminase assays to monitor cell damage throughout the perfusion. Additionally, the output of the pressure, flow, temperature, and oxygen sensors was monitored and recorded to track the health of the organ during perfusion and assess the system's capability of maintaining the quality of data over time. RESULTS: The results show the system is capable of successfully perfusing porcine livers for up to three hours. Functionality and viability assessments show no deterioration of liver cells once normothermic perfusion had occurred and bile production was within normal limits of approximately 26 ml in 90 min showing viability. CONCLUSION: The developed low-cost perfusion system presented here has been shown to keep porcine livers viable and functional ex vivo. Additionally, the system is capable of easily incorporating several sensors into its framework and simultaneously monitor and record them during perfusion. The work promotes further exploration of the system in different research domains.

Evaluation of A Novel Organ Perfusion Research Platform.

This paper presents a novel, low cost, organ perfusion machine designed for use in research. The modular and versatile nature of the system allows for additional sensing equipment to be added or adapted for specific use. Here we introduce the system and present its preliminary evaluation by assessing its ability to maintain a predetermined input pressure. A proportional-integral-derivative (PID) controller was implemented and tested on a porcine liver to maintain input pressure to the hepatic artery and compared to bench tests. The results confirmed the effectiveness of the controller for maintaining input through the hepatic artery (HA) in a timely manner. Clinical Relevance-Machine Perfusion (MP) is proving to be an invaluable adjunct in clinical practice. With its ongoing success in the transplant arena, we propose MP for use in research. A cost-effective, versatile system that can be modified for specific research use to test new pharmacological therapies, imaging techniques or develop simulation training would be beneficial.

The effect of pH on citric acid cough challenge: A randomised control trial in chronic cough and healthy volunteers.

INTRODUCTION: Citric acid has been used for over six decades to induce cough; however the mechanism of its pro-tussive effect is still not fully understood. We assessed the response to inhalation of citric acid at varying levels of acidity to determine if the pH of the solution plays a role in the induction of cough. Data was collected from both healthy volunteers and patients with chronic cough. METHODS: 20 chronic cough patients and 20 healthy volunteers were recruited and underwent three cough challenges on separate days. Each visit involved 5 repeated one second inhalations of 300 mM citric acid solution. The concentration of the citrate cation remained constant, but the pH of the solution altered by the addition of sodium bicarbonate to 3, 5 and 6, representing the pKa values of the individual acid moieties. The total number of coughs elicited was recorded for each inhalation. RESULTS: Two subjects withdrew and were not included in the analysis. Participants were gender matched, each group consisting of 12 females. 74% of chronic coughers coughed at pH 3 (mean coughs 16), 89% coughed at pH 5 (18) and 63% coughed at pH 6 (7). In healthy volunteers, 60% of subjects coughed at pH 3 (9), 30% of subjects coughed at pH 5 (3), and 10% of subjects coughed at pH 6 (0). Thus chronic cough patients coughed more than healthy volunteers and did not exhibit a clear pH concentration response. There was also a greater variability in their response to individual challenges.