Figure 1: Fstl1 Levels Are Increased in HFpEF

(A) Follistatin-like 1 (Fstl1) serum levels in patients with heart failure with preserved ejection fraction (HFpEF) (n = 32) versus control subjects (Control) (n = 8). (B) Fstl1 protein levels in adult rat cardiac myocytes (ARVM) stimulated with aldosterone (Aldo) 1 μmol/l (n = 5 per group). (C) Fstl1 mRNA and (D) protein levels and representative immunohistochemistry of Fstl1 staining in the left ventricle of Sham (E) and HFpEF (F) mice (n = 5 to 7 mice/group). Black arrows in E and F indicate Fstl1 staining. Data are mean ± SEM. Statistical analysis by 2-tailed Student t test. GAPDH = glyceraldehyde 3-phosphate dehydrogenase

Figure 6: Lack of Cardiac Myocyte Fstl1 in HFpEF Does Not Affect Cardiac Fibrosis

(A) Cardiac fibrosis in the left ventricle (LV) (left, representative Masson trichrome images, original magnification ×400) and myocardial fibrosis area (right) in WT and cFslt1-KO mice subjected to aldosterone (HFpEF) or saline (Sham) infusion. (B) Collagen 1 and 3 mRNA expression in WT and cFslt1-KO mice after aldosterone (HFpEF) or saline (Sham) infusion. n = 6 to 12 mice/group. Data are mean ± SEM. Statistical analysis by analysis of variance followed by (A) Newman-Keuls multiple comparison tests and (B) Kruskal-Wallis test followed by Dunn test

Figure 3: Systemic Intravenous Delivery of Fstl1 Ameliorates Cardiac Hypertrophy and Reduces E/A Ratio in Wild-Type HFpEF Mice

(A) Heart weight/body weight ratio. (B) Ratio of peak E velocity to peak A velocity (E/A). Wild-type HFpEF (aldosterone infusion) and Sham (saline infusion) mice were injected, 2 weeks after HFpEF induction, with an adenoviral vector producing either β-galactosidase (Ad-βgal: 1 × 109 plaque-forming units) as control, or Fstl1 (Ad-Fstl1: 1 × 109 plaque-forming units) (n = 3 to 4 mice/group). Data are mean ± SEM. Statistical analysis by analysis of variance (ANOVA) followed by Newman-Keuls multiple comparison tests. Abbreviations as in Figure 1

Visual Abstract - Follistatin-Like 1 Regulates Hypertrophy in Heart Failure With Preserved Ejection Fraction: 10.1016/j.jacbts.2016.04.002

• Fstl1, also known as transforming growth factor-β–stimulated clone 36, is an extra-cellular glycoprotein implicated in the pathophysiology of cardiac disease.• Fstl1 acts in a noncanonical manner relative to other follistatin family members, but its functions remain poorly understood.• Circulating Flst1 levels are increased in humans with chronic stable HFpEF.• Fstl1 treatment modulates cardiomyocyte hypertrophy in vitro and in vivo.• Cardiac myocyte deletion of Fstl1 worsens the HFpEF phenotype in mice.• These studies indicate that Fstl1 may be therapeutically effective in HFpEF by modulating cardiac hypertrophy and improving parameters of diastolic dysfunction.</div

Figure 5: Lack of Fstl1 Increases Cardiac Myocyte Hypertrophy in HFpEF Mice

(A) Cardiac myocyte hypertrophy in the left ventricle (LV) (left, representative hematoxylin and eosin images, scale bar: 10 μm) and quantitative measure of cardiac myocyte cross-sectional area (right). (B) Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) mRNA expression in WT and cFslt1-KO mice with aldosterone (HFpEF) or saline (Sham) infusion. n = 6 to 12 mice/group. Data are mean ± SEM. Statistical analysis by analysis of variance followed by Newman-Keuls multiple comparison tests. Abbreviations as in Figures 1 and 4

Figure 4: HFpEF Is Aggravated in Cardiac Myocyte-Specific Fstl1 KO Mice

(A) Tail cuff systolic blood pressure (BP) recorded weekly for 4 weeks in wild-type (WT) and cFslt1-KO mice infused with aldosterone (HFpEF) or saline (Sham) (n = 10-12 mice per group). (B) Heart weight/body weight ratio and (C) wet lung/dry lung ratio in WT and cardiac myocyte-specific Fstl1 knockout (cFslt1-KO) mice (n = 5 to 10 mice/group). Diastolic function assessed 4 weeks after aldosterone (HFpEF) or saline (Sham) infusion in WT and cFslt1-KO mice (n = 10 to 12 mice/group). (D) Representative pulse wave and tissue Doppler images. (E) Left ventricular compliance measured as ratio of peak E velocity to peak A velocity (E/A), and (F) diastolic filling pressure evaluated as ratio of peak E velocity to peak é velocity. Data are mean ± SEM. Statistical analysis by analysis of variance followed by Newman-Keuls multiple comparison tests. A = peak late transmitral flow velocity; E = peak early transmitral flow velocity; é = peak early diastolic myocardial velocity; other abbreviations as in Figure 1

Figure 2: Treatment With Fstl1 Decreases Cardiac Myocyte Hypertrophy Induced By Aldosterone in Adult Rat Ventricular Myocytes

(A)3H-Leucine incorporation and (B) atrial natriuretic peptide (ANP) mRNA expression in adult rat ventricular myocytes after 30-min pre-treatment with 100 ng/ml recombinant human Fstl1 protein (rFstl1) and 18-h treatment with 1 μmol/l aldosterone (Aldo). n = 6 to 12 samples/group. Data are mean ± SEM. Statistical analysis by Kruskal-Wallis test followed by Dunn test. Abbreviations as in Figure 1