Green tea extract as a treatment for patients with wild-type transthyretin amyloidosis: an observational study

Abstract

Background: Causative treatment of patients with wild-type transthyretin amyloid cardiomyopathy (wtATTR-CM) is lacking. Recent reports indicate the potential use of epigallocatechin-3-gallate (EGCG), the most abundant catechin in green tea, to inhibit amyloid fibril formation. We sought to investigate changes of cardiac function and morphology in patients with wtATTR-CM after consumption of green tea extract (GTE).

Methods: Twenty-five male patients (71 [64; 80] years) with wtATTR-CM were submitted to clinical examination, echocardiography, cardiac magnetic resonance imaging (cMRI) (n=14), and laboratory testing before and after daily consumption of GTE capsules containing 600 mg epigallocatechin-3-gallate for at least 12 months.

Results: A significant decrease of left ventricular (LV) myocardial mass by 6% (196 [100; 247] vs 180 [85; 237] g; P=0.03) by cMRI and total cholesterol by 8.4% (191 [118; 267] vs 173 [106; 287] mg/dL; P=0.006) was observed after a 1-year period of GTE consumption. LV ejection fraction by cMRI (53% [33%; 69%] vs 54% [28%; 71%]; P=0.75), LV wall thickness (17 [13; 21] vs 18 [14; 25] mm; P=0.1), and mitral annular plane systolic excursion (10 [5; 23] vs 8 [4; 13] mm; P=0.3) by echocardiography remained unchanged.

Conclusion: This study supports LV mass stabilization in patients with wtATTR-CM consuming GTE potentially indicating amyloid fibril reduction.

Keywords: EGCG; cardiomyopathy; polyphenol; wild-type ATTR.

Figure 1

Laboratory testing. Notes: Levels of cholesterol (A), LDL cholesterol (B), NT-proBNP (C), and glomerular filtration rate calculated using the MDRD formula (D) of individual patients with wtATTR-CM determined by cMRI before and after 12 months of green tea extract consumption. Abbreviations: cMRI, cardiac magnetic resonance imaging; LDL, low-density lipoprotein; MDRD, modified diet in renal disease; t₀, baseline; t₁₂, at 12 months; wtATTR-CM, wild-type transthyretin amyloid cardiomyopathy; NT-proBNP, N-terminal prohormone of brain natriuretic peptide.

Figure 2

Echocardiography findings. Notes: Interventricular septum thickness (A) and inferior wall thickness (B) of individual patients with wtATTR-CM determined by echocardiography before and after 12 months of green tea extract consumption. Abbreviations: t₀, baseline; t₁₂, at 12 months; wtATTR-CM, wild-type transthyretin amyloid cardiomyopathy.

Figure 3

cMRI findings. Notes: LV myocardial mass (A) and LVEF (B) of individual patients with wtATTR-CM determined by cMRI before and after 12 months of green tea extract consumption. Abbreviations: cMRI, cardiac magnetic resonance imaging; LV, left ventricular; LVEF, LV ejection fraction; t₀, baseline; t₁₂, at 12 months; wtATTR-CM, wild-type transthyretin amyloid cardiomyopathy.

Figure 4

LV myocardial mass (A) and LVEF (B) of patients with wtATTR-CM who underwent assessment by cMRI with green tea extract consumption for longer than 1 year. Abbreviations: cMRI, cardiac magnetic resonance imaging; LV, left ventricular; LVEF, LV ejection fraction; t₀, baseline; t₁₂, at 12 months; t₁₇, at 17 months; t₂₅, at 25 months; t₃₀, at 30 months; t₄₄, at 44 months; wtATTR-CM, wild-type transthyretin amyloid cardiomyopathy.