Research ArticleAtrial Fibrillation

Cardiac glial cells release neurotrophic S100B upon catheter-based treatment of atrial fibrillation

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Science Translational Medicine  22 May 2019:
Vol. 11, Issue 493, eaav7770
DOI: 10.1126/scitranslmed.aav7770
  • Fig. 1 S100B in the human ICNS.

    (A) Photograph of a human heart showing a posterior view of the left atrium (LA) and the pulmonary veins where cardiac ganglia and nerves are located. (B) Anatomical three-dimensional map of the LA (posterior view). The red dots show the areas in which AF ablation via PVI is performed. (C) Preprocedural S100B plasma concentrations in patients receiving a sole diagnostic EPS versus patients receiving an ablation of the muscular CTI versus AF ablation (PVI) [EPS: n = 19, CTI: n = 20, PVI: n = 112; data presented as box plots (minimum to maximum); P < 0.05 was considered statistically significant; compared using Kruskal-Wallis test]. ns, not significant. (D) S100B content of human atrial pectinate muscles per gram of tissue (n = 5 tissue samples, data presented as means ± SEM). (E) Immunohistological staining of S100B, TUBB3, and RAGE in intracardiac ganglia, cardiac nerves, and delicate nerve fibers within the atrial myocardium. LSPV, left superior pulmonary vein; RSPV, right superior pulmonary vein; LIPV, left inferior pulmonary vein; RIPV, right inferior pulmonary vein; LAA, left atrial appendage; RA, right atrium; LV, left ventricle; RV, right ventricle.

  • Fig. 2 Plasma S100B in patients undergoing AF ablation.

    (A) Pre- to postprocedural S100B concentrations (ΔS100B) in patients receiving AF ablation (PVI) compared with sole diagnostic EPS or ablation of the muscular CTI [EPS: n = 19, CTI: n = 20, PVI: n = 112; data presented as box plots (minimum to maximum); ****P < 0.0001, compared using Kruskal-Wallis test]. (B) Changes of pre- to postprocedural troponin I (ΔhsTnI) between the groups (EPS: n = 14, CTI: n = 19, PVI: n = 101; ****P < 0.0001, compared using Kruskal-Wallis test). (C) Normalization of ΔS100B/ΔhsTnI was performed to account for tissue damage (****P < 0.0001, compared using Mann-Whitney test). (D) Change in patients’ HR after AF ablation, EPS, or CTI (only patients in sinus rhythm; EPS: n = 15, CTI: n = 9, PVI: n = 72; ***P = 0.0008, compared using Kruskal-Wallis test with Dunn’s posttest for multiple comparison against EPS group). (E) S100B concentrations in patients with and without recurrences of AF [number of patients: none, n = 67; 0 to 3 months, n = 29; 3 to 6 months, n = 19; data are presented as box plots (minimum to maximum); *P = 0.0076, compared using Kruskal-Wallis test]. (F) Kaplan-Meier curve of freedom from AF stratified by plasma concentrations of ΔS100B (n = 103; P = 0.028).

  • Fig. 3 S100B release from the ICNS in murine hearts ex vivo.

    S100B expression in the murine ICNS in nerve fibers (A) and intracardiac ganglia (B), as shown by the costaining with choline acetyltransferase (ChAT). White boxed region is shown at higher magnification in the rightmost panel. S100B+ glial cells are marked with white arrows in the magnification. (C) Photograph of a murine heart showing the area surrounding the pulmonary veins where cryogenic damage was generated (black box). (D) S100B measured in the perfusion fluid before and after cryogenic damage in ex vivo mouse hearts (n = 8; **P = 0.0045, compared using paired t test). (E) Histological characterization of a murine heart after acute cryoablation. H&E staining of a murine cardiac ganglion without (left) and with acute signs of thermal damage (right) from a heart after ex vivo cryoablation. Cellular shrinkage marked by black arrows. (F) Staining of ChAT and S100B in cryodamaged ganglia. Glial cells are marked by white arrows. White boxed region in the merged panel is shown at higher magnification in the rightmost panel.

  • Fig. 4 S100B diminishes neuronal, but not myocardial, AP firing.

    (A) Exemplary trains of APs evoked by long-lasting (500 ms) depolarizing current pulses (150 pA, amplitude) in control conditions (upper trace), and 10 min after application of recombinant S100B (100 ng/ml) (lower trace) in single murine intracardiac neurons. (B) Plot showing the time course of the effect of S100B on firing frequency in single murine intracardiac neurons. (C) Averaged normalized AP frequency from intracardiac neurons as a function of time in the absence (TimeCTRL) and the presence of S100B [TimeCTRL n = 6 cells, S100B n = 5 cells; *P < 0.05, compared using two-way repeated-measures analysis of variance (ANOVA)]. (D) Exemplary AP shape in human atrial pectinate muscles at basal state and upon exposure to S100B (100 ng/ml) (n = 3 independent experiments). (E) Continuous measurement of AP duration at 90% of repolarization (APD90) in human atrial myocardium (paced at 1 Hz) from 5 min before to 20 min after the superfusion with S100B (100 ng/ml). (F) Cardiac electrophysiological parameters in control hearts and hearts infused with recombinant S100B [n = 6 per group; data are presented as box plots (minimum to maximum); compared using Mann-Whitney or unpaired t test as appropriate; P < 0.05 was considered statistically significant]. ARP, atrial refractory period; WBP, Wenckebach period; AVNRP, AV nodal recovery period; VRP, ventricular refractory period.

  • Fig. 5 S100B is taken up by intracardiac neurons and increases neurite outgrowth.

    (A) Ex vivo murine hearts stained for S100B showing enrichment in intracardiac nerves and ganglia after infusion of recombinant S100B (100 ng/ml, 90 min). Boxed regions are shown at higher magnification. (B) Images and (C) quantification of neurite lengths in murine intracardiac neurons cultivated for 18 hours with recombinant S100B (100 ng/ml) [positive control: 5% fetal calf serum n = 29, negative control n = 108, S100B (100 ng/ml) n = 113; data are presented as means ± SEM and represent five independent experiments with two to four replicates per condition; **P = 0.0011, ***P = 0.0009; groups were compared with Kruskal-Wallis and Dunn’s posttest for multiple comparisons against negative control]. (D) Quantification of S100B in plasma from patients before and 1 day after ablation (n = 17; **P = 0.002, compared using paired t test).

Supplementary Materials

  • stm.sciencemag.org/cgi/content/full/11/493/eaav7770/DC1

    Fig. S1. S100B-expressing glial cells ensheathing nerve fibers are interspersed within the human atrial myocardium.

    Fig. S2. S100B-expressing glial cells ensheathing sympathetic nerve fibers.

    Fig. S3. Patient with reduced phrenic nerve activity during ablation presents a higher increase in S100B plasma concentration.

    Fig. S4. Activin A increase independent of ablation type.

    Table S1. Baseline characteristics of patients.

    Table S2. Changes in HR variability parameters in patients after AF ablation.

    Table S3. Electrophysiological measurements in human atrial pectinate muscles after exposure to S100B.

    Table S4. Primary antibodies used in this study.

    Table S5. Secondary antibodies used in this study.

    Reference (66)

  • This PDF file includes:

    • Fig. S1. S100B-expressing glial cells ensheathing nerve fibers are interspersed within the human atrial myocardium.
    • Fig. S2. S100B-expressing glial cells ensheathing sympathetic nerve fibers.
    • Fig. S3. Patient with reduced phrenic nerve activity during ablation presents a higher increase in S100B plasma concentration.
    • Fig. S4. Activin A increase independent of ablation type.
    • Table S1. Baseline characteristics of patients.
    • Table S2. Changes in HR variability parameters in patients after AF ablation.
    • Table S3. Electrophysiological measurements in human atrial pectinate muscles after exposure to S100B.
    • Table S4. Primary antibodies used in this study.
    • Table S5. Secondary antibodies used in this study.
    • Reference (66)

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