Humoral immune responses to hyaluronan oligosaccharides in patients undergoing prosthetic valve surgery

Figures

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  Figure 1. Serum antibodies against the disaccharide unit of hyaluronan (HA2) measured via ELISA. (A) IgG antibodies. (B) IgM antibodies. Longitudinal analyses are shown for cohorts B1 (de novo BHV implantation) and B1C (de novo MHV or CABG), with serum samples collected before surgery (I) and at 1, 6, 12, and 24 months post-operatively (M-1, M-6, M-12, and M-24). For cohorts B2 (≥4 years post-BHV without SVD), B2C (≥4 years post-MHV implantation or CABG), and A (SVD), only the initial sample obtained at study inclusion was analyzed. The results are expressed in μg/mL as median values with interquartile ranges (25th–75th percentiles). (*p < 0.05; **p < 0.01; ***p < 0.001).

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  Figure 2. Serum antibodies against the hyaluronan fragment HA24 (12 disaccharide units) measured by ELISA. (A) IgG antibodies. (B) IgM antibodies. Longitudinal analyses are shown for cohorts B1 (de novo BHV implantation) and B1C (de novo MHV or CABG), with serum samples collected before surgery (I) and at 1, 6, 12, and 24 months post-operatively (M-1, M-6, M-12, and M-24). For cohorts B2 (≥4 years post-BHV without SVD), B2C (≥4 years post-MHV implantation or CABG), and A (SVD), only the initial sample obtained at study inclusion was analyzed. The results are expressed in μg/mL as median values with interquartile ranges (25th–75th percentiles). (*p < 0.05; **p < 0.01; ***p < 0.001).

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  Figure 3. Serum antibodies against the hyaluronan fragment HA84 (42 disaccharide units) measured by ELISA. (A) IgG antibodies. (B) IgM antibodies. Longitudinal analyses are shown for cohorts B1 (de novo BHV implantation) and B1C (de novo MHV or CABG), with serum samples collected before surgery (I) and at 1, 6, and 12 months post-operatively (M-1, M-6, and M-12). The results are expressed in μg/mL as median values with interquartile ranges (25th–75th percentiles). (*p < 0.05; **p < 0.01; ***p < 0.001).

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  Figure 4. Antibody recognition of HA oligosaccharides assessed via PGA analysis. The heatmap depicts log2 reactivity against 20 structurally defined HA oligosaccharides, ranging from the disaccharide unit (HA2) to 20 repeating disaccharide units (HA40). (A) Longitudinal analysis for Group B1 (de novo BHV implantation; n = 12) with serum samples collected before surgery (I) and at 1, 6, 12, and 24 months post-surgery (M-1, M-6, M-12, and M-24). (B) Longitudinal analysis for Group B1C (de novo MHV or CABG; n = 8) with samples collected at the same time points as those for Group B1. (C) Baseline and 12-month (M-12) analysis for Group B2 (≥4 years post-BHV without SVD). (D) Baseline and 12-month (M-12) analysis for Group B2C (≥4 years post-MHV implantation or CABG). (E) serum sample obtained from Group A (SVD) patients. The color scale applies to all the heatmaps.

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  Figure 5. Fragment-length-dependent generation, function, and immune recognition of hyaluronan (HA). (A) During tissue injury, inflammation, and remodeling, high–molecular–weight HA is degraded by hyaluronidases and oxidative processes, generating a spectrum of HA fragments rather than a random distribution. (B) HA fragment size determines biological activity. Short fragments (HA2–HA20) primarily function as damage-associated molecular patterns, activating innate immune pathways, whereas intermediate fragments (HA32–HA40) more efficiently engage receptors such as CD44 and RHAMM, promoting cell migration, angiogenesis, and matrix remodeling. (C) Antibody recognition of HA is fragment-length– and assay-dependent. ELISA preferentially detects abundant, low- to moderate-affinity antibodies that bind short fragments such as HA2, while PGA analysis highlights higher-affinity, conformation-sensitive antibodies that recognize intermediate-length fragments, particularly HA34.