Circulating syndecans during critical illness

Circulating syndecans are proposed to be markers of glycocalyx degradation and previous investigations have found higher plasma levels of syndecan-1 among patients with different pathological conditions. We wanted to investigate if levels of other syndecans (-2,-3 and -4) are altered during critical illness and compare the levels to syndecan-1. In 137 consecutive intensive care unit (ICU) patients with sepsis, cardiac arrest, gastrointestinal bleeding, intoxication or trauma, plasma levels of syndecan-1, -2, -3 and -4 were measured using ELISA. Syndecan-1 and syndecan-3 levels were similar among the different ICU patient groups but higher than controls. No differences in plasma levels of syndecan-2 or syndecan-4 were found neither among the different ICU patient groups nor compared to controls. All syndecans showed an association with mortality and the levels of syndecan-1 and -3 and correlated with each other. The results indicate that syndecan release is triggered by the physiological stress of critical illness in general and involves several subtypes such as syndecan-1 and syndecan-3.