Additional file 1: of Association of sublingual microcirculation parameters and endothelial glycocalyx dimensions in resuscitated sepsis

Table S1. Summary of microcirculation and endothelial glycocalyx parameters [16, 25]. Figure S1. Analysis of the endothelial glycocalyx (eGC) in cell culture via atomic force microscopy (AFM). Surface approach: the cantilever (AFM tip) approaches the sample surface vertically. The reflection of a laser beam from the back of the cantilever is continuously detected by a photodiode. First slope: reaching the surface, the cantilever, serving as a soft spring, is deflected while indenting into the sample. The changing laser beam reflection is plotted as a function of sample position along the z-axis. By including the cantilever’s spring constant and the optical lever sensitivity, a force-versus-indentation curve can be generated to provide information about how much force (in pN) is needed to indent a certain distance (in nm) into the sample. The first slope of the curve reflects the indentation of the eGC. Second slope: in the second slope, more force is needed to indent into the surface, which reflects the cell cortex with the plasma membrane and actin web. Due to the linearity of the first slope, a regression line can be generated manually through the starting points of both slopes using PUNIAS (protein unfolding and nano-indentation analysis software, version 1.0, release 2.1, http://punias.free.fr). Projected to the x-axis, the distance between both starting points represents the thickness of the eGC [38, 39]. Table S2. Baseline characteristics of septic patients stratified for sepsis duration. Figure S2. Endothelial glycocalyx dimensions measured in vivo and in vitro. Scatter plot showing the association between AFM-derived eGC thickness (in vitro) and corresponding PBR values (in vivo) in three apparently healthy individuals (white circles) and in three septic patients (black circles). Each circle represents the mean of three independent experiments (consisting of ≥ 5 indentation curves in each of ≥ 10 cells) for each individual serum. Incubation without human serum served as control. Data are presented as mean ± SEM. Table S3. Correlations of PBR, PPV, MFI, age, sex, and comorbidities in the septic cohort. Spearman correlation was used. The p values are indicated in brackets. Table S4. Simple and multiple linear regression (PBR as dependent variable). Dependent variable: PBR. Table S5. Correlations of microcirculatory and eGC parameters in the septic cohort. Spearman correlation was used. The p values are indicated in brackets. Figure S3. Correlations of microcirculation and endothelial glycocalyx parameters. (A–C): Correlation of PBR with PVD, PPV, and MFI. (D–F): Correlation of syndecan-1 with PVD, PPV, and MFI. Figure S4. MFI (eyeballing) obtained in real-time with the two different systems. (A): Correlation between the MFI (eyeballing) values obtained at the bedside. (B): Bland-Altman plot showing the limits of agreement (bias ± 1.96 SD) between paired MFI values for the Cytocam and GlycoCheck™ system (eyeballing). One point can represent more than one individual. (DOCX 606 kb)