Immune-inflammatory dysregulation modulates the incidence of progressive fibrosis and diastolic stiffness in the aging heart.
Diastolic dysfunction in the aging heart is a grave condition that challenges the life and lifestyle of a growing segment of our population. This report seeks to examine the role and interrelationship of inflammatory dysregulation in interstitial myocardial fibrosis and progressive diastolic dysfunction in aging mice. We studied a population of C57BL/6 mice that developed progressive diastolic dysfunction over 30 months of life. This progressive dysfunction was associated with increasing infiltration of CD45(+) fibroblasts of myeloid origin. In addition, increased rates of collagen expression as measured by cellular procollagen were apparent in the heart as a function of age. These cellular and functional changes were associated with progressive increases in mRNA for MCP-1 and IL-13, which correlated both temporally and quantitatively with changes in fibrosis and cellular procollagen levels. MCP-1 protein was also increased and found to be primarily in the venular endothelium. Protein assays also demonstrated elevation of IL-4 and IL-13 suggesting a shift to a Th2 phenotype in the aging heart. In vitro studies demonstrated that IL-13 markedly enhanced monocyte-fibroblast transformation. Our results indicate that immunoinflammatory dysregulation in the aging heart induces progressive MCP-1 production and an increased shift to a Th2 phenotype paralleled by an associated increase in myocardial interstitial fibrosis, cellular collagen synthesis, and increased numbers of CD45(+) myeloid-derived fibroblasts that contain procollagen. The temporal association and functional correlations suggest a causative relationship between age-dependent immunoinflammatory dysfunction, fibrosis and diastolic dysfunction.
Baylor College of Medicine, One Baylor Plaza, M.S. BCM620, Houston, TX 77030, USA. cieslik@bcm.edu
Katarzyna A
KA
Cieslik
George E
GE
Taffet
Signe
S
Carlson
Jesus
J
Hermosillo
Joann
J
Trial
Mark L
ML
Entman
D000375:Aging / Q000502:physiology*; D000818:Animals; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism; D003971:Diastole / Q000235:genetics / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005355:Fibrosis / Q000235:genetics / Q000378:metabolism*; D005434:Flow Cytometry; D007150:Immunohistochemistry; D018793:Interleukin-13 / Q000235:genetics / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009206:Myocardium / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D040081:Protein Array Analysis
D018932:Chemokine CCL2; D018793:Interleukin-13; D017493:Leukocyte Common Antigens