The Effects of Antibiotics and Storage on the Viability and Ultrastructure of Fibroblasts in Canine Heart Valves Prepared for Grafting1

Abstract

lortac und pulmonary valve cusps f r o m mongrel dogs were suspended tit a nutrient medium and exposed for one week at 4' C to an antibiotic solution and were thereafter stored in nutrient medium without antibiotics at 4" C. The cusps were subjected to tissue culture and ncirroscopic exainination at intervals ranging f r o m one day to five weeks after collectzon. Growlh of fibroblasts was noted on tissue culture in 93% of ousps after 24 hours, in 61% rrftcr oiw zc'cek and in 15% after two weeks. There wus no growth beyond two zc$ecks. Elertron iiiicrosropx fxamination showed progressively severe ultrastructural changes recog?ki;ablc cifter the cusps had been in the antibiotic solution for 24 hours. This and other studies on human material make it clear that satisfactory function of antibiotic-sterilized valve allografts is not primarily dependent on viable graft fibroblasts.THE clinical results of cardiac valve replacements with aortic and pulmonary valve allografts have improved a great deal in recent years. This has been contributed to by modifications in the methods of preparing the grafts (Rirratt-&yes and Roche, 1969 ; Gerbode, ivoci: Barratt-noyes et a%, 1972), and some workers have suggested that maintenance of (lonor cell viability is an important consideration (Angell r t a%, I972 ; Angell et alii, 1 9 7 3~) .This paper reports and discusses the effects produced by preserving canine aortic and pulmonary valve cusps by the methods currently in clinical use at Green Lane Hospital. MATERIALS A N D METHODSAortic and pulmonary valve cusps were obtained from 63 mongrel dogs within one hour of death. The cusp\ were removed by a clean, but not a sterile tcchniqiie, and were immediately placed in Hanks's halanced salt solution. The cusps were then taken to the tissue culture lahoratory, where they were transferred to jars containing Medium 199 (Commonwealth Serum Laboratory, Melbourne). Membranefiltcretl fetal calf 5erum (Australian Laboratory Services, Rockdale) was added to make up 10% of the volume of the solution. A stock solution of antibiotics was finally added to give a concentration per milli-Supported hy a grant from The Medical Re-Reprint?. Sir Brian Barratt-Boyes, Green Lane search Council. I I m p i t a l , \iickland 3, New Zealand. litre of 50 units of penicillin, I mg of streptomycin,

Pathology Of Explanted Cryopreserved Allograft Heart Valves: Comparison With Aortic Valves From Orthotopic Heart Transplants

“…Although cell injury during ischemia and cryopreservation of allograft valves is well documented, 11,12 some workers report long-term survival of certain cellular elements in both experimental systems and explanted allografts from human recipients. 2,[13][14][15] In one study, viable fibroblasts were routinely cultured from explanted cryopreserved allografts. 2 Some of these may derive from recipient pannus, as our identification of vimentin and smooth-muscle actinpositive cells in one long-term implant suggests.…”

Tracheal Homograft as Aortic Conduit: Early Phase Results

“…Sterilization procedures have also been shown to affect negatively the two factors thought to influence long-term survival: fibroblast viability and host ingrowth into and onto the implants. [16][17][18][19][20] Many different formulas have been advocated since 1968 to overcome these problems . [20][21][22] The potential for microorganisms in tracheal grafts because of atmospheric communication necessitates antibiotic treatment.…”

A comparison of antibiotic-sterilized, stent-mounted pulmonary and aortic valve allografts in the mitral region of dogs

“…In the present experimental study the same antibiotic solution as that in use clinically since 1968 (Barratt-Boyes, 1971) has been employed. With this method, tissue culture (Girinath, Gavin, Strickett, and Barratt-Boyes, 1974) and electron microscopic studies (Gavin, Monro, Wall, and Chalcroft, 1973c) indicate that the fibroblasts are structurally damaged and following even short periods of contact with the antibiotics they do not survive implantation in the host for longer than a few weeks (Gavin, Herdson, Monro, and Barratt-Boyes, 1973b). Persistent normal function of the leaflet is thus dependent primarily on the integrity of the fibrous tissue.…”