Glycocalyx damage biomarkers in healthy controls, abdominal surgery, and sepsis: a scoping review

Objective: Despite wide interest in glycocalyx biomarkers, their values in healthy individuals, patients after abdominal surgery, and septic patients have been poorly understood. Methods: We searched MEDLINE, CENTRAL and EMBASE for papers measured glycocalyx biomarkers in healthy individuals, patients after abdominal surgery and septic patients. Results: We extracted 3948 titles and identified 58 eligible papers. Syndecan 1 was the most frequently measured biomarker (48 studies). Its mean or median value in healthy individuals varied to a biologically implausible degree, from 0.3 to 58.5 ng/ml, according to assay manufacturer. In post-operative patients, syndecan 1 levels increased after pancreatic surgery or liver surgery, however, they showed minor changes after hysterectomy or laparoscopic surgery. In septic patients, biomarker levels were higher than in healthy volunteers when using the same assay. However, six healthy volunteer studies reported higher syndecan 1 values than after pancreatic surgery and 24 healthy volunteer studies reported higher syndecan 1 values than the lowest syndecan 1 value in sepsis. Similar findings applied to other glycocalyx biomarkers. Conclusion: Glycocalyx damage biomarkers values are essentially defined by syndecan 1. Syndecan 1 levels, however, are markedly affected by assay type and show biologically implausible values in normal, post-operative, or septic subjects.