PROMINENCE OF APOLIPOPROTEIN-B, APOLIPOPROTEIN-(A), AND APOLIPOPROTEIN-E IN THE INTIMAE OF CORONARY-ARTERIES IN TRANSPLANTED HUMAN HEARTS -GEOGRAPHIC RELATIONSHIP TO VESSEL WALL PROTEOGLYCANS

Background: Transplant arteriopathy (TA) is characterized by vessel wa ll thickening with prominent glycosaminoglycan and lipid deposits. In this light, we have recently demonstrated the distribution of proteogl ycans in allograft coronary arteries. The aim of this study is to exam ine the distribution of apolipoproteins within allograft coronary arte ries and to investigate their localization in relation to proteoglycan s. Method: Particular transverse sections of left and right epicardial coronary arteries from 46 human cardiac allografts, 11 normal hearts, and 11 hearts with native atherosclerosis were stained immunohistoche mically for apolipoprotein B, apolipoprotein (a) (apo[a]), apolipoprot ein E (apoE), biglycan, decorin, and versican by use of an automated i mmunostainer. Results: Apo(a) and apoE immunopositivity in TA was much more intense than that in native atherosclerosis, whereas the reverse was true for apoB. Prominent apoE deposits were evident circumferenti ally in endothelia and extracellularly in superficial intima of mildly diseased TA, as well as in deeper intima of severely diseased TA. Apo (a) had a staining pattern very similar to apoE except for a patchy de position also seen in TA media. The intimal areas staining prominently with apoE or apo(a) in TA arteries corresponded very closely to the a reas with proteoglycan deposits, especially versican. Conclusion: The distinctive patterns of apolipoprotein accumulation in TA and native a therosclerosis appear to reflect different pathogenetic processes in t he two conditions. The colocalization of proteoglycans and apolipoprot eins in TA intima supports the hypothesis that interactions between pr oteoglycans and apolipoproteins influence lipid retention and overload in allograft coronary arteries.