Primary plexogenic pulmonary hypertension shows imperfect formation of the internal elastic lamina of the pulmonary arteries

Age-related changes among 25 patients with congenital cardiac left-to-right shunts and irreversible plexogenic pulmonary arteriopathy

BACKGROUND

Some patients with congenital heart disease and irreversible plexogenic pulmonary arteriopathy survive into adulthood. The purpose of this study was to compare histopathological and antigen expression patterns in adults and children with congenital heart disease and plexogenic pulmonary arteriopathy.

METHODS

Autopsy/explant lung tissues from 25 patients with congenital heart disease and plexogenic pulmonary arteriopathy were reviewed for 24 histopathological parameters associated with plexogenic pulmonary arteriopathy, including the prevalence and character of plexiform lesions. Immunohistochemistry using antibodies against CD31, C-kit, smooth muscle actin, CD68, and Fli-1 was performed to evaluate plexiform lesions.

RESULTS

Group 1 consisted of 14 patients aged <20 years, and Group 2 included 11 patients aged >or=20 years (range, 20-69 years). Cellular plexiform lesions trended toward greater prevalence in Group 1 than in Group 2 (P=.081), whereas involuted plexiform lesions more frequently affected Group 2 than Group 1 (P=.0037). In addition, recent platelet-fibrin thrombi within plexiform lesions occurred more often in Group 1 than in Group 2 (P=.0419). Intimal proliferation/fibrosis of elastic arteries and pulmonary vein dilation were more common in Group 2 (P=.0172 and P=.0048, respectively). CD31 and C-kit staining in non-lumen-lining cells of plexiform lesions was more frequent in Group 2 than in Group 1 (P=.0858 and P=.0173, respectively). No statistically significant differences in expression patterns between cellular and involuted plexiform lesions existed.

CONCLUSIONS

Among patients with congenital heart disease and plexogenic pulmonary arteriopathy, histopathological differences were observed between those surviving into adulthood and those dying in childhood/adolescence. Plexiform lesions in adults undergo remodeling from a cellular morphology to an involuted morphology. It is unclear whether this simply represents the natural progression of plexiform lesions or also confers a survival advantage.

Suppression subtractive hybridization identifies distinctive expression markers for coronary and internal mammary arteries

OBJECTIVE

We sought to identify differentially expressed genes in the athero-prone coronary artery and athero-resistant internal mammary arteries.

METHODS AND RESULTS

Using suppressive subtraction hybridization, we generated reciprocal cDNA collections of representative mRNAs specific to porcine coronary arteries versus porcine mammary arteries. We screened 1000 suppressive subtraction hybridization cDNA clones by dot blot array and sequenced 600 of those showing the most marked expression differences. Northern blot, in situ hybridization, and immunostaining confirmed the differential gene expression patterns identified by the dot blot arrays. Genes associated with mammary arteries included claudin-10 and h-cadherin, which are genes associated with tight junctions and intermediate junctions. In contrast, genes associated with proatherosclerotic processes, such as lipid retention and metabolism, inflammation, and cell growth, were preferentially expressed in coronary arteries.

CONCLUSIONS

Normal coronary arteries have gene expression program that is significantly different than internal mammary arteries. These differences may partly explain the resistance of coronary arteries and internal mammary arteries to atherosclerosis.