Safety, acceptability, and feasibility of acquiring endothelial cells from guidewires in patients having major surgery or with acute critical illness

Abstract Background Endothelial cells (EC) play a key role in vascular homeostasis, and endothelial dysfunction has been linked to the development of cardiovascular disease. While most EC research relies on indirect assessment of EC function in humans, in vitro systems and in vivo animal models, the development of a safe protocol to isolate EC from patients would provide a new window into EC function. Purpose To assess (a) the feasibility of isolating EC from discarded guidewires used as part of the standard of care (SOC) in surgical patients and patients admitted to intensive care (ICU) and (b) to compare EC phenotypes in the patient cohorts. Methods Discarded guidewires were collected from arterial lines and central venous catheters (CVC) from 15 patients before abdominal surgery and 16 patients admitted to ICU requiring organ support. Additionally, J-wires were inserted into forearm veins using an proven technique for EC biopsy (ECBx) in all surgical patients. ECs were dissociated from guidewires, stained for CD31, CD144, CD202b, and nuclear integrity then analysed using flow-cytometry. EC were characterised based on surface marker expression and granularity. Blood biomarkers and clinical information was collected. Organ function was assessed using sequential organ failure assessment (SOFA). Tolerability and adverse event (AE) data was also collected using structured interviews to support the analysis. Results From the surgical cohort 6 arterial lines, 14 CVC and 15 ECBx were collected. From the ICU patients, 8 arterial lines and 9 CVC were collected. EC were identified as live and triple positive for CD31, CD144, CD202b. A median of 536 (IQR 160-796 ) EC were obtained from arterial lines, 622 (IQR 329-1045) from CVCs and 768 (IQR 210-1001) from ECBx with no significant difference between method of collection (Kruskal-Wallis p>0.05). Median granularity showed a significant increase in granularity in EC collected from ICU patients compared to the surgical patients. This could be attributed to internalisation of cell surface proteins or apoptosis caused by the hyperinflammatory conditions in ICU patients (SOFA 7, IQR 5-8.25, CRP 118, IQR 66.2-298) when compared to the surgical patients (SOFA 1, IQR 0-2, CRP <4mg/l). Median fluorescent intensity analysis of all three markers did not show a significant difference between patient groups. AEs to ECBx reported only 4 patients experienced light bruising. High tolerability was reported for ECBx by structured interview, with patients agreeing that they theoretically would tolerate up to 3 ECBx. Conclusion(s) It is feasible to isolate ECs from patients during SOC using discarded guidewires. As an isolated procedure, ECBx from forearm veins is well tolerated and carries low risk. This enables the characterisation of EC phenotypes and obtain unique insight in their roles in health and disease.