Old Drug, New Trick: Tilorone, a Broad-Spectrum Antiviral Drug as a Potential Anti-Fibrotic Therapeutic for the Diseased Heart

Figure 1. Anti-fibrotic effects of tilorone in human left ventricular cardiac fibroblasts in vitro. Tilorone attenuates TGFβ stimulated collagen synthesis in human left ventricular cardiac fibroblasts. Data analysed using a one-way ANOVA with Tukey’s post hoc test. Data passed Shapiro–Wilk test for normality. n = 3 independent experiments (average of 6 technical replicates per experiment). Lines indicate the mean. * p < 0.05.

Figure 2. Tilorone does not attenuate TAC-induced cardiac hypertrophy. Heart weight (HW) and atria weight (AW) normalised to tibial length (TL). Data analysed using a two-way ANOVA with Fisher’s post hoc test. n = 3 (sham groups), 7 (TAC groups). Lines indicate the mean. * p < 0.05.

Figure 3. Tilorone attenuates TAC-induced fibrosis and is associated with a favourable fibrotic gene expression profile. (A) Representative left ventricular cross-sections stained with Masson’s trichrome from sham and TAC male mice treated with either saline or tilorone, and quantification of fibrosis. Scale bar = 200 μM. Data analysed by a one-way ANOVA with Fisher’s post hoc test. Lines represent the mean. n = 3 (sham groups), 7 (TAC groups). (B) qPCR quantification of Col1a1 and Ctgf gene expression relative to Hprt1 in Sham and TAC saline and tilorone treated hearts. Data analysed using a two-way ANOVA with Fisher’s post hoc test. Lines represent the mean. n = 3 (Sham groups), 7 (TAC groups). * p < 0.05.

Figure 4. Treatment with tilorone is associated with a favourable cardiac stress gene expression profile. qPCR quantification of Nppa (Anp), Nppb (Bnp), Acta1 (α skeletal actin) and Myh7 (β-MHC) gene expression relative to Hprt1 in Sham and TAC saline and Tilorone treated hearts. Data analysed using a two-way ANOVA with Fisher’s post hoc test. Lines represent the mean. n = 3 (sham groups), 7 (TAC groups). * p < 0.05.

Figure 5. Treatment with tilorone prevented a further decline in cardiac function. Top: Representative M-modes at baseline, 4 weeks post-TAC and endpoint. Bottom: Quantification of fractional shortening at baseline (pre-surgery), 4 weeks post-TAC (prior to saline/tilorone administration), and 8 weeks post-treatment (i.e., 12 weeks post-TAC). Saline/tilorone treatment commenced at 4 weeks post-TAC. Data analysed using a two-way Repeated Measures ANOVA with Fisher’s post hoc test. Lines represent the mean. n = 7 (TAC groups). * p < 0.05.

Figure 6. Experimental Outlines. (A) Timeline of animal study design. (B) Schematic demonstrating experimental workflow for the radioisotopic assay to determine collagen synthesis in vitro.

Figure 7. Experimental Animals and exclusions. A flowchart for the reporting of animal use, allocation, experimental analysis and exclusions following the CONsolidated Standards of Animal Experiment ReporTing (CONSAERT).