PAC1 deficiency reduces chondrogenesis in atherosclerotic lesions of hypercholesterolemic ApoE-deficient mice.

BACKGROUND: Induction of chondrogenesis is associated with progressive atherosclerosis. Deficiency of the ADCYAP1 gene encoding pituitary adenylate cyclase-activating peptide (PACAP) aggravates atherosclerosis in ApoE deficient (ApoE-/-) mice. PACAP signaling regulates chondrogenesis and osteogenesis during cartilage and bone development. Therefore, this study aimed to decipher whether PACAP signaling is related to atherogenesis-related chondrogenesis in the ApoE-/- mouse model of atherosclerosis and under the influence of a high-fat diet. METHODS: For this purpose, PACAP-/-/ApoE-/-, PAC1-/-/ApoE-/-, and ApoE-/- mice, as well as wildtype (WT) mice, were studied under standard chow (SC) or cholesterol-enriched diet (CED) for 20 weeks. The amount of cartilage matrix in atherosclerotic lesions of the brachiocephalic trunk (BT) with maximal lumen stenosis was monitored by alcian blue and collagen II staining on deparaffinized cross sections. The chondrogenic RUNX family transcription factor 2 (RUNX2), macrophages [(MΦ), Iba1+], and smooth muscle cells (SMC, sm-α-actin) were immunohistochemically analyzed and quantified. RESULTS: ApoE-/- mice fed either SC or CED revealed an increase of alcian blue-positive areas within the media compared to WT mice. PAC1-/-/ApoE-/- mice under CED showed a reduction in the alcian blue-positive plaque area in the BT compared to ApoE-/- mice. In contrast, PACAP deficiency in ApoE-/- mice did not affect the chondrogenic signature under either diet. CONCLUSIONS: Our data show that PAC1 deficiency reduces chondrogenesis in atherosclerotic plaques exclusively under conditions of CED-induced hypercholesterolemia. We conclude that CED-related chondrogenesis occurs in atherosclerotic plaques via transdifferentiation of SMCs and MΦ, partly depending on PACAP signaling through PAC1. Thus, PAC1 antagonists or PACAP agonists may offer therapeutic potential against pathological chondrogenesis in atherosclerotic lesions generated under hypercholesterolemic conditions, especially in familial hypercholesterolemia. This discovery opens therapeutic perspectives to be used in the treatment against the progression of atherosclerosis.

Characterization of atherosclerotic plaques in blood vessels with low oxygenated blood and blood pressure (Pulmonary trunk): role of growth differentiation factor-15 (GDF-15).

BACKGROUND: Growth differentiation factor (GDF)-15 is linked to inflammation, cancer, and atherosclerosis. GDF-15 is expressed in most tissues but is extremely induced under pathological conditions. Elevated serum levels are suggested as a risk factor and a marker for cardiovascular diseases. However, the cellular sources and the effects of GDF-15 on the cardiovascular system have not been completely elucidated including progression, and morphology of atherosclerotic plaques. Thus, this work aimed to characterize the influence of GDF-15 deficiency on the morphology of atherosclerotic plaques in blood vessels with low-oxygen blood and low blood pressure as the pulmonary trunk (PT), in hypercholesterolemic ApoE-/- mice. METHODS: GDF-15-/- ApoE-/- mice were generated by crossbreeding of ApoE-/-- and GDF-15-/- mice. After feeding a cholesterol-enriched diet (CED) for 20 weeks, samples of the brachiocephalic trunk (BT) and PT were dissected and lumen stenosis (LS) was measured. Furthermore, changes in the cellularity of the PT, amounts of apoptosis-, autophagy-, inflammation- and proliferation-relevant proteins were immunohisto-morphometrically analyzed. Additionally, we examined an atherosclerotic plaque in a human post mortem sample of the pulmonary artery. RESULTS: After CED the body weight of GDF-15-/-ApoE-/- was 22.9% higher than ApoE-/-. Double knockout mice showed also an 35.3% increase of plasma triglyceride levels, whereas plasma cholesterol was similar in both genotypes. LS in the BT and PT of GDF-15-/-ApoE-/- mice was significantly reduced by 19.0% and by 6.7% compared to ApoE-/-. Comparing LS in PT and BT of the same genotype revealed a significant 38.8% (ApoE-/-) or 26.4% (GDF-15-/-ApoE-/-) lower LS in the PT. Immunohistomorphometry of atherosclerotic lesions in PT of GDF-15-/-ApoE-/- revealed significantly increased levels (39.8% and 7.3%) of CD68 + macrophages (MΦ) and α-actin + smooth muscle cells than in ApoE-/-. The density of TUNEL + , apoptotic cells was significantly (32.9%) higher in plaques of PT of GDF-15-/-ApoE-/- than in ApoE-/-. Analysis of atherosclerotic lesion of a human pulmonary artery showed sm-α-actin, CD68+, TUNEL+, Ki67+, and APG5L/ATG+ cells as observed in PT. COX-2+ and IL-6+ immunoreactivities were predominantly located in endothelial cells and subendothelial space. In BT and PT of GDF15-/-ApoE-/- mice the necrotic area was 10% and 6.5% lower than in ApoE-/-. In BT and PT of GDF15-/-ApoE-/- we found 40% and 57% less unstable plaques than ApoE-/- mice. CONCLUSIONS: Atherosclerotic lesions occur in both, BT and PT, however, the size is smaller in PT, possibly due to the effect of the low-oxygen blood and/or lower blood pressure. GDF-15 is involved in atherosclerotic processes in BT and PT, although different mechanisms (e.g. apoptosis) in these two vessels seem to exist.

Effect of cholesterol re-supplementation and atorvastatin on plaque composition in the thoracic aorta of New Zealand white rabbits.

BACKGROUND: Effects of re-supplementation of a cholesterol-enriched diet (CEDrs) on size, cholesterol content and morphology of already existing plaques are not known to date. METHODS: A group of rabbits received standard chow (SC) for 6 weeks ("negative control"; for plasma lipid measurements only). Group I-IV received 2% CED (induction) for 6 weeks; thereafter, groups II-IV have been fed a SC (= cholesterol withdrawal) for 68 weeks. Afterwards, feeding of groups II-IV was continued as follows: Group II - 10 weeks SC, group III - 4 weeks 0.5% CED (~re-supplementation), afterwards 6 weeks SC (~withdrawal again); group IV - 4 weeks 0.5% CED (re-supplementation) + atorvastatin (2.5 mg/kg body weight/day), afterwards 6 weeks SC (~withdrawal again) + atorvastatin. Plasma lipids, but also plaque size, morphology and cholesterol contents of thoracic aortas were quantified. RESULTS: After CEDrs, plasma cholesterol levels were increased. However, after withdrawal of CEDrs, plasma cholesterol levels decreased, whereas the cholesterol content of the thoracic aorta was increased in comparison with the group without CEDrs. Plaque size remained unaffected. Atorvastatin application did not change plasma cholesterol level, cholesterol content of the thoracic aorta and plaque size in comparison with the group without drug treatment. However, atorvastatin treatment increased the density of macrophages (MΦ) compared with the group without treatment, with a significant correlation between densities of MΦ (Mac-1+) and apoptotic (TUNEL+; TP53+), antigen-presenting (HLA-DR+) or oxidatively stressed (SOD2+) cells. CONCLUSIONS: In rabbits with already existing plaques, CEDrs affects plaque morphology and cellular composition, but not plaque size. Despite missing effects on plasma cholesterol levels, cholesterol content of the thoracic aorta and size of already existing atherosclerotic plaques, atorvastatin treatment transforms the already existing lesions to a more active form, which may accelerate the remodelling to a more stable plaque.

[Rise in gamma-GT during anticonvulsive therapy]. / Erhöhung der Gamma-GT bei antikonvulsiver therapie.

There have been several reports of the isolated occurrence of raised serum gamma GT levels in the course of long-term anticonvulsive treatment. The findings concerning the correlation between this elevation of gamma GT and various dimensions of epilepsy or treatment regimens are equivocal. In a retrospective study of 158 epileptics, the mean values of the serum gamma GT level have been grouped according to anticonvulsive regimen and compared with one another, as well as correlated to the serum concentration of the antiepileptic drug. An elevation of serum gamma GT was found in 103 patients. Among the different subgroups the mean value for serum gamma GT was raised in cases under treatment with PHT, PB or PRM. No such elevation was found in cases under monotherapy with CBZ or VPR. The elevation of serum gamma GT is considered to reflect hepatic enzyme induction rather than hepatic impairment.

Hospitalized chronic alcoholic patients without field-dependent performance in the rod-and-frame test.

Hospitalized male chronic alcoholics (n = 60) fully employed and with no history of malnutrition were compared with matched nonalcoholic controls (n = 50) on the Rod-and-Frame Test (RFT). The RFT scores of the alcoholics were not significantly worse than those of the controls. This is in marked contrast to earlier reports of RFT field dependence in unemployed, indigent alcoholics and supports Burdick's findings with the Embedded Figures Test.