Allen M D, Shoji Y, Fujimura Y, Gordon D, Thomas R, Brockbank K G, Disteche C M
Department of Surgery, University of Washington, Seattle 98195.
Circulation. 1991 Nov;84(5 Suppl):III94-9.
Growth characteristics and cell viability of aortic and pulmonic valve homografts in the systemic circulation were compared in a growing sheep model. Seven aortic and seven pulmonic cryopreserved homografts were implanted in the descending aortae of recipient female lambs. Of seven sheep per group, three were killed at 8 months, three at 12 months, and one at 15 months. Tissue cultures were obtained on homograft valve and root wall specimens. Male donor cells were identified by chromosome analysis. Preimplant to explant changes in pulmonic homograft external diameters at the valve annulus and sinotubular junction increased significantly more than in aortic roots. The postoperative dimensions of the distal anastomotic diameter and length of the graft increased significantly more in pulmonic than in aortic roots by time of explant. Leaflet calcification and valvular stenosis did not develop in either pulmonic or aortic homografts over the period of observation. Calcification in the root wall was significantly less in pulmonic than aortic homografts. Growth on tissue culture was obtained from over 70% of homograft specimens. Viable donor cells were demonstrated in none and 43% of aortic and pulmonic leaflets, respectively, and 71% and 57% of aortic and pulmonary arterial homograft walls, respectively. In conclusion, both aortic and pulmonic homograft valves provide freedom from calcification and stenosis in this model. Continuing expansion of pulmonic root diameters under systemic pressure might lead to late aneurysm formation. Although host cell repopulation of grafts may be advantageous, the presence of viable donor cells in leaflet tissue does not seem necessary to prevent calcific degeneration.
在一个绵羊生长模型中，比较了主动脉和肺动脉瓣同种异体移植物在体循环中的生长特性和细胞活力。将七个主动脉和七个肺动脉冷冻保存的同种异体移植物植入受体雌性羔羊的降主动脉。每组七只绵羊中，三只在8个月时处死，三只在12个月时处死，一只在15个月时处死。从同种异体移植瓣膜和根壁标本上获取组织培养物。通过染色体分析鉴定雄性供体细胞。肺动脉同种异体移植物在瓣环和窦管交界处的外径从植入前到取出时的变化明显大于主动脉根部。到取出时，肺动脉移植物远端吻合口直径和长度的术后尺寸增加明显大于主动脉根部。在观察期内，肺动脉或主动脉同种异体移植物均未出现瓣叶钙化和瓣膜狭窄。肺动脉根壁的钙化明显少于主动脉同种异体移植物。超过70%的同种异体移植标本在组织培养中生长。在主动脉和肺动脉瓣叶中，分别没有和有43%的活供体细胞被证实，在主动脉和肺动脉同种异体移植壁中，分别有71%和57%的活供体细胞被证实。总之，在这个模型中，主动脉和肺动脉同种异体移植瓣膜均无钙化和狭窄。在体循环压力下肺动脉根部直径的持续扩大可能导致晚期动脉瘤形成。尽管宿主细胞重新填充移植物可能是有利的，但瓣叶组织中存在活供体细胞似乎不是防止钙化变性所必需的。
