Combination of ALX and FSK preserved cardiac function during CCS
Cardiac function assessed at the end of animal models using echocardiogram demonstrated cardiac function deteriorated during CCS. Compared with the PCH mice and ALX single therapy, FSK single therapy improved cardiac function to some extent, but it was accompanied by arrhythmias. However, the combination of ALX and FSK preserved cardiac function most effectively compared to the single therapy groups (Fig. 5a-5c, Supplementary Fig. S4 and Table S2). There was no statistical significance upon comparing cardiac functions of mice from the PCH-preventive combine therapy group with Ctrl and Vhl mice. The Vhl mice group is representing the Ctrl mice group as well in results illustrations due to similarity in their data.
A further critical assessment of molecular alterations in the apical myocardium across all groups demonstrated that overall, the combination of ALX and FSK preserved cardiac function during CCS by normalizing expressions of the proteins and TFs that play critical roles in cardiac function and immune response modulation.
Among the therapeutic groups, β1AR depletion was minimized by the combined therapy, while β2AR expression was somewhat maintained across all the groups. Compared to the Vhl and PCH mice, the expression of AC5 and AC7 were mostly normalized by the combined therapy, although FSK single treatment did better against ALX single treatment. AC6 was still observed increasing its expression in stress intensity-dependent manner across groups. Even though ALX alone inhibited GRK5 activities, it had no inhibitory effect on GRK2; neither did only FSK. FSK single treatment also minimized the upregulation of GRK5 but not as effective as ALX single treatment and their combined treatment. The combination therapy again was the best in regulating ANP and BNP expressions during CCS (Fig. 6a). The normalization of ACs by the combination therapy was translated into normalized cAMP concentrations as well (Fig. 6b).
Intriguingly, despite the inhibition GRK5 by the ALX single treatment, ERK1/2 was maladaptively engaged, and the TFs; GATA4, NFAT, MEF2, and NF-κB were upregulated just like in PCH mice. FSK single therapy did better at modulating the overexpression of these cardiac and inflammatory TFs, but the ALX and FSK combination therapy did best (Fig.7)