Authors' Reply.

This correspondence is a reply to Galectin-3, Cardiac Function, and Fibrosis by Wouter C. Meijers et al.

Myocardial Galectin-3 Expression Is Associated with Remodeling of the Pressure-Overloaded Heart and May Delay the Hypertrophic Response without Affecting Survival, Dysfunction, and Cardiac Fibrosis.

The β-galactoside-binding animal lectin galectin-3 is predominantly expressed by activated macrophages and is a promising biomarker for patients with heart failure. Galectin-3 regulates inflammatory and fibrotic responses; however, its role in cardiac remodeling remains unclear. We hypothesized that galectin-3 may be up-regulated in the pressure-overloaded myocardium and regulate hypertrophy and fibrosis.

CXCR3-independent actions of the CXC chemokine CXCL10 in the infarcted myocardium and in isolated cardiac fibroblasts are mediated through proteoglycans.

Aims: The CXC chemokine CXCL10 is up-regulated in the infarcted myocardium and limits cardiac fibrosis by inhibiting growth factor-mediated fibroblast migration. CXCL10 signals by binding to its receptor CXCR3; however, recently CXCR3-independent CXCL10 actions have been suggested. Our study explores the role of CXCR3 signalling in myocardial infarction and investigates its involvement in mediating the anti-fibrotic effects of CXCL10.

Thrombospondin-1 induction in the diabetic myocardium stabilizes the cardiac matrix in addition to promoting vascular rarefaction through angiopoietin-2 upregulation.

Rationale: Diabetes mellitus is associated with cardiac fibrosis. Matricellular proteins are induced in fibrotic conditions and modulate fibrogenic and angiogenic responses by regulating growth factor signaling.

Objective: Our aim was to test the hypothesis that the prototypical matricellular protein thrombospondin (TSP)-1, a potent angiostatic molecule and crucial activator of transforming growth factor-β, may play a key role in remodeling of the diabetic heart.