Growth Differentiation Factor 15 Inhibits Cardiac Fibrosis, Oxidative Stress, Inflammation, and Apoptosis in a Rat Model of Heart Failure with Preserved Ejection Fraction.

Background: Heart failure with preserved ejection fraction (HFpEF) is a systemic syndrome primarily associated with fibrosis, oxidative stress, inflammation, and cellular apoptosis. Growth differentiation factor 15 (GDF15), a biomarker commonly used in clinical studies, exhibits protective effects on the myocardium. Therefore, the focus of the present study is to determine the mechanism by which GDF15 protects cardiac function in HFpEF.

Methods: We conducted functional enrichment analysis and protein-protein interaction network analysis on genes highly expressed in HFpEF but lowly expressed in normal samples. We established an HFpEF rat model by feeding the rats with a high-fat diet and administering N-omega-nitro-l-arginine-methyl ester (L-NAME) in their drinking water and silenced GDF15 by tail vein injection of lentivirus (L3110). After 12 weeks of feeding, echocardiographic examinations were performed. Following euthanasia of the rats, blood and heart tissue samples were collected. Heart tissue sections were stained using Masson's trichrome and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining methods. Western blot (WB) analysis was employed to determine the concentrations of relevant proteins.

Results: The echocardiographic results showed that compared with the HFpEF + MOCK group, the HFpEF+silencing GDF15 (siGDF15) group exhibited more severe cardiac dysfunction, with significant decreases in ejection fraction (p < 0.05) and E/A ratio (p < 0.001). WB results demonstrated that, compared with the HFpEF + MOCK group, the HFpEF+siGDF15 group exhibited increased expression of cardiac fibrosis-associated proteins, including collagen I (p < 0.01), collagen III (p < 0.01), and α-smooth muscle actin (α-SMA) (p < 0.01). Additionally, oxidative stress-associated biomarkers such as myeloperoxidase (MPO) (p < 0.01) and oxidized low-density lipoprotein (ox-LDL) (p < 0.01), inflammation-associated biomarkers, including interleukin-1 beta (IL-1β) (p < 0.01), interleukin-6 (IL-6) (p < 0.01), interleukin-8 (IL-8) (p < 0.01), and tumor necrosis factor α (TNFα) (p < 0.01), and apoptosis-associated biomarkers like cleaved caspase-3 (p < 0.01) and BCL2-associated X (BAX) (p < 0.01) were also upregulated in HFpEF+siGDF15 group.

Conclusions: Our research indicates that GDF15 preserves cardiac function by inhibiting myocardial fibrosis, reducing myocardial cell oxidative stress, alleviating cardiac inflammation, and suppressing myocardial cell apoptosis.