Increased expression of peroxisome proliferator-activated receptor (PPAR)-alpha and PPAR-gamma in human atherosclerosis.

To clarify the mechanism of atherosclerosis development in humans, we studied the mRNA and protein expression of PPAR subtypes in various types of atherosclerotic lesions and their correlation with cell proliferation and macrophage invasion. Human aortas were obtained from 35 autopsied cases, and each sample was divided into halves. One half was used for the analysis of mRNA or protein expression with RT-PCR or Western blotting, respectively. The other was microscopically classified into atheromatous plaque (AP), fatty streak (FS), and diffuse intimal thickening (DIT), and was analyzed immunohistochemically. The mRNA levels of both PPARs increased significantly in atherosclerosis and tended to increase in proportion to the severity of the lesion, and the expression of PPAR-alpha correlated with that of PPAR-gamma in FS and AP. The PPAR-gamma protein increased in AP. Monocytes/macrophages, as well as endothelial and smooth muscle cells, expressed the PPAR-gamma protein in plaques. This expression in the DIT was noted mainly in macrophages but was not correlated with the density of macrophages, suggesting that only certain macrophages express the PPARs in DIT. Cell proliferation did not correlate with PPARs expression in any lesion type. These findings suggest that PPARs may be associated with atheromatous plaque formation, and that PPAR-gamma may be involved in the early stages of human atherosclerosis.

Ubiquitin-positive foam cells are identified in the aortic and mitral valves with atherosclerotic involvement.

AIM: Our aim was to determine the roles of the ubiquitin (Ub)-proteasome system (UPS) in valvular diseases by immunohistochemically identifying Ub-positive cells in aortic and mitral valves and determining if Ub+cells were associated with the severity of valvular diseases. METHODS: We evaluated surgically removed aortic and mitral valves from 60 patients (mean age, 64.5 years) for thickening, fibrosis, foam cell infiltration, thrombus, and atheromatous plaques by using grading scores. U+cells were detected immunohistochemically. RESULTS: We found Ub+cells in 16 (26.7%) of the 60 patients. Eleven (28.2%) of the 39 aortic valves and 5 (23.8%) of the 21 mitral valves were Ub-positive. Ub was found with granular depositions in the cytoplasm of monocyte-derived foam cells that were CD68+. The aortic valvular thickness of the Ub+group was significantly greater than that of the Ub- group (3.9+/-1.6mm vs. 3.2+/-1.6mm, p<0.05). Foam cells and fibrosis were greater in the Ub+group (p<0.05), and calcifications were prominent in aortic valves. There was no difference in the number of apoptotic cells in Ub+ and Ub- groups. Ub+cells were present in the affected valves and ubiquitinated proteins were accumulated in macrophage-derived foam cells. CONCLUSIONS: Ub+ foam cells are present in valves that are vulnerable to valvular disease, and UPS may contribute to the development of atherosclerosis through the inflammatory process.

Reduced airway inflammation and remodeling in parallel with mucin 5AC protein expression decreased by s-carboxymethylcysteine, a mucoregulant, in the airways of rats exposed to sulfur dioxide.

BACKGROUND: Human obstructive airway diseases are histopathologically characterized by inflammatory cell infiltration, goblet cell hyperplasia, and mucus hypersecretion in airways. We prepared a rat model of airway injury by exposure of sulfur dioxide (SO2) and then evaluated the effects of S-carboxymethylcysteine (S-CMC), a mucoregulant. METHODS: Rats were exposed to SO2 gas for 44 days and orally given S-CMC at 250 mg/kg, twice daily, from 21 to 44 days of exposure for histopathological and immunohistochemical evaluation. RESULTS: SO2 exposure induced inflammatory cell infiltration and mucus cell increase in rat airways. S-CMC treatment significantly decreased this inflammatory cell infiltration in proximal and peripheral airways. Morphometrically, SO2 exposure significantly increased the number of Alcian blue (pH 2.5)- and periodic acid-Schiff (AB/PAS)-positive cells in rat airways (11.8 x 10(-2) cell/nuclear profiles per micrometer basement membrane) compared to normal rat airways (1.6 x 10(-2) cell/nuclear profiles per micrometer basement membrane). S-CMC treatment significantly decreased the number of AB/PAS-positive cells (4.4 x 10(-2) cell/nuclear profiles per micrometer basement membrane, p < 0.01 vs. SO2-exposed rats). Immunohistochemically, SO2 exposure increased the expression of mucin 5AC (MUC5AC) protein in the airway epithelium of rats, but S-CMC treatment inhibited the increase. CONCLUSIONS: The increased mucus cells and MUC5AC protein expression seem associated with SO2-induced airway inflammation in rats. The fact that S-CMC suppresses airway inflammation and the increase in mucus cells and MUC5AC protein expression suggests that this mucoregulant may be advantageous in the treatment of inflammatory airway diseases with goblet cell hyperplasia.

[Atherosclerotic regression in the aortas of elderly. (4). Expression of peroxisome proliferator-activated receptors with references of centrally depressed atherosclerotic plaque].

Peroxisome proliferator-activated receptors (PPARs) play an important role in vascular events during progression of atherosclerosis, associated with lipid metabolism, inflammatory response and others. To clarify relationships between the expression of PPARs subtypes and regression, we studied mRNA expression of PPARs subtypes with reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry, especially in centrally depressed atherosclerotic plaques (depressed plaque) in the aortas of elderly patients, and proposed morphological feature of atherosclerotic regression. Samples were separated from the depressed plaque, atheromatous plaque, and diffuse intimal thickening (DIT) in the aortas of elderly patients at autopsy and they were analyzed for RT-PCR. The depressed plaques obtained were divided into two parts: depressed area and surrounding elevated area. Total RNA was prepared, using the TRIzol Reagent, and was reverse transcribed using random hexamer primers and Thermoscript kit for RT-PCR. Immunohistochemical analysis was processed for mouse anti-PPAR gamma antibody, detected by the ABC method. 1) Decreased foam cells were found in the depressed area than in the surrounding elevated area of the depressed plaque. These foam cells were immunohistochemically positive for HAM56 and strong reactivities for PPAR gamma were found in the nuclei of macrophage-derived foam cells. PPAR gamma was also detected in the nuclei of endothelial cells and smooth muscle cells. 2) Expressions of PPAR alpha and PPAR gamma were found in the depressed plaques with RT-PCR. These expressions were found both in the depressed area and the surrounding elevated area without significant differences. 3) PPAR gamma mRNA expression both in the depressed area and the surrounding elevated area, was greater than in DIT, and was less than in the atheromatous plaque. 4) Expression of PPAR gamma mRNA was intense and increased in the surrounding elevated area than in the depressed area. 5) A significant increase of PPAR gamma expression was found in the atheromatous plaque than in the DIT. 6) There was no significant difference of PPAR alpha mRNA expression between the depressed area and the surrounding elevated area. The depressed plaque has been considered to be a morphological characteristic of regression in recent studies. Expression of mRNA for PPARs was detected in the depressed plaque as well as the atheromatous plaque, furthermore, there were different expressions and intensity of PPARs between the depressed area and the surrounding elevated area of the depressed plaque. These findings suggest that the expression of PPARs may be involved not only in the progression of atherosclerosis but also in regression.