Tricuspid valve biopsy: a potential source of cardiac myofibroblast cells for tissue-engineered cardiac valves.
OBJECTIVE
As progress is made in the development of a tissue-engineered cardiac valve, the need for a reliable cell source is particularly important. A technique has been developed for the reliable biopsy of tricuspid valve leaflets. Expanding the harvested cells in culture is feasible and provides a source of leaflet cells that are structurally and functionally similar to the pulmonary and aortic valve leaflet cells that they may replace.


METHODS
Thirteen sheep underwent tricuspid valve biopsy. Transthoracic echocardiography (TTE) was performed to evaluate function and guide the subsequent biopsy. Myofibroblasts were isolated from the biopsy samples, expanded in culture through 10 passages, and evaluated with immunocytochemistry for valve cell markers. Two animals were sacrificed acutely, two animals died during the immediate postoperative period, and nine animals survived for four weeks or more.


RESULTS
All preoperative and pre-explantation echocardiograms were normal. Both animals sacrificed acutely showed that the tricuspid valve leaflet was indeed biopsied with this technique. Two perioperative deaths occurred; one animal died secondary to injury of the chorda tendinea with subsequent destruction of the posterior leaflet; another died from disruption of the superior vena cava that led to irreversible cardiac tamponade. At sacrifice (2 to 17 weeks), all other animals showed intact tricuspid valves with normal leaflet anatomy. All cultured biopsies generated myofibroblasts that were immunocytochemically positive for alpha smooth muscle actin, chondroitin sulfate, vimentin and fibronectin.


CONCLUSIONS
Biopsy of the tricuspid valve to obtain recipient cardiac valve leaflet cells is possible, and the technique is simple and reliable. Biopsy of the leaflet does not compromise function. Interstitial cells can be harvested and expanded in culture. Cellular structure and function is preserved and is similar to that of other cardiac leaflet cells. Tricuspid valve leaflet biopsies are a potential source for harvesting cells to be used in the development of a tissue-engineered cardiac valve.
Maish
Mary S
MS
Department of Surgery, Brown University School of Medicine and The Collis Cardiac Surgery Research Laboratory of the Rhode Island Hospital, Providence, Rhode Island, USA.
Hoffman-Kim
Diane
D
Krueger
Paula M
PM
Souza
Jason M
JM
Harper
James J
JJ
Hopkins
Richard A
RA
D000199:Actins / Q000378:metabolism; D000818:Animals; D001706:Biopsy; D002478:Cells, Cultured; D002809:Chondroitin Sulfates / Q000378:metabolism; D004195:Disease Models, Animal; D017548:Echocardiography, Transesophageal; D004801:Eosine Yellowish-(YS); D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D005456:Fluorescent Dyes; D006416:Hematoxylin; D007150:Immunohistochemistry; D008297:Male; D008955:Models, Cardiovascular; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology; D012756:Sheep; D013194:Staining and Labeling; D023822:Tissue Engineering; D014261:Tricuspid Valve / Q000378:metabolism / Q000473:pathology*; D014481:United States; D014746:Vimentin / Q000378:metabolism
D000199:Actins; D016326:Extracellular Matrix Proteins; D005456:Fluorescent Dyes; D014746:Vimentin; D002809:Chondroitin Sulfates; D004801:Eosine Yellowish-(YS); D006416:Hematoxylin