Summary
A medRxiv preprint analysed 344 postoperative drain-fluid samples from 67 pancreatic and colorectal surgery patients. It found that leakage was associated with different protein patterns over time in the two types of surgery.
A medRxiv preprint has mapped how proteins in postoperative drain fluid change over time in patients undergoing pancreatic or colorectal surgery. The analysis found that leakage associated with the two procedures followed different molecular patterns, suggesting that detection strategies may need to account for the type of operation.
The study included 33 pancreatic surgery patients, whose 201 drain-fluid samples were analysed, and 34 colorectal surgery patients, providing 143 samples. Samples were collected across an observation window of up to 10 days after surgery. The work is a preprint and is framed as biomarker discovery rather than as a validated clinical diagnostic study.
A time-resolved view of postoperative leakage
Anastomotic leakage is a complication in which fluid escapes from a surgically created connection in the gastrointestinal tract. Clinicians can test drain fluid for selected enzymes or other indicators, but postoperative inflammation and healing can make early interpretation difficult.
The researchers used longitudinal data-independent acquisition proteomics. Proteomics measures the abundance of many proteins in a biological sample; the data-independent approach is designed to capture broad protein information across repeated samples rather than restricting analysis to a small, predefined panel. This allowed the team to compare protein trajectories in patients with and without leakage during the postoperative period.
In pancreatic surgery, the established enzyme markers AMY2A and PNLIP showed strong early separation between leakage and non-leakage patients. The pancreatic leakage pattern was characterised first by enzyme enrichment during postoperative days 1 to 3, followed later by proteins associated with inflammation, antimicrobial activity, oxidative stress and tissue-matrix remodelling.
The colorectal results had a different timing and composition. The strongest divergence appeared around postoperative day 3, and the pattern was driven largely by lower levels of proteins involved in wound healing. These included proteins associated with endothelial integrity, extracellular-matrix organisation, complement regulation and coagulation balance.
Candidate markers for future validation
The procedure-specific patterns also produced four candidate proteins for further study. PRSS2 and AZU1 were identified in the pancreatic surgery analysis, while FBLN1 and CDH5 emerged from the colorectal surgery analysis. The authors describe these as candidates whose diagnostic potential requires follow-up validation studies.
The results suggest that leakage is not necessarily represented by one shared drain-fluid signature across gastrointestinal operations. Instead, the biological processes visible in drain fluid may depend on the tissues involved, the surgical reconstruction and the timing of sampling. That distinction could help guide the design of future biomarker panels that combine routine enzyme measurements with broader protein measurements.
The evidence currently comes from two relatively small patient cohorts and a postoperative observation period of up to 10 days. The four newly proposed markers therefore remain research candidates. The preprint also reports that Alexander Jessernig and Inge K. Herrmann are inventors on a patent for anastomotic-leak detection filed by ETH Zurich and Empa, an interest relevant to interpreting the findings.