Phenotypic expression of a novel desmin gene mutation: hypertrophic cardiomyopathy followed by systemic myopathy.

Hypertrophic cardiomyopathy is a heterogeneous disease caused by gene mutations. Most of the disease-causing mutations were found in the genes for sarcomeric proteins, but there are several cases carrying mutations in genes for extra-sarcomeric cytoskeletons. Desmin is a member of extra-sarcomeric cytoskeletons and plays an important role in muscle contraction. Mutations in the desmin gene cause various type of general myopathy and/or cardiomyopathy, known as desmin-related myopathies. We identified a novel desmin missense mutation, Thr219Pro, in the homozygous state in a patient, who first manifested with hypertrophic cardiomyopathy and later progressed to general myopathy. His parents were heterozygous for the mutation, but showed no clinical abnormality, suggesting the recessive inheritance of the mutation. We here report a severe phenotype of hypertrophic cardiomyopathy preceded the onset of general myopathy caused by a novel homozygous missense mutation in the 1B α-helix domain of desmin.

Reduction in morning blood pressure is a key factor for ameliorating urinary albumin excretion in patients with morning hypertension irrespective of treatment regimen.

BACKGROUND: The Morning Hypertension and Angiotensin Receptor Blocker/Hydrochlorothiazide Combination Therapy (MAPPY) study has shown that losartan/hydrochlorothiazide (HCTZ) combination is superior to high-dose losartan in not only reducing morning systolic blood pressure (SBP) but also ameliorating urinary albumin excretion (UAE) after 3-month treatment. The purpose of the present study was to investigate factors associated with UAE reduction in on-treatment patients with morning hypertension. METHODS AND RESULTS: A total of 95 patients registered in the MAPPY study were analyzed. Patients were treated with either a losartan/HCTZ combination regimen (n=47) or a high-dose losartan regimen (n=48). Three-month treatment significantly reduced morning SBP, evening SBP, and clinic SBP (P<0.001, P<0.05, and P<0.01, respectively). UAE and serum uric acid were significantly decreased (P<0.01 for both) without the change in estimated glomerular filtration rate. Multiple linear regression analysis indicated that %morning SBP reduction and baseline UAE were independent determinants of the UAE reduction (P=0.001 for both). After adjustments for the reduction in morning-evening SBP difference, baseline UAE, and %uric acid reduction, estimated %UAE reduction level was positively correlated with the tertiles of the increasing %morning SBP reduction level (P=0.031 for trend). Moreover, subgroup analysis showed that morning SBP reduction was an independent determinant of UAE reduction in both treatment regimens. CONCLUSIONS: Reduction in morning SBP was a key factor in UAE reduction in patients with morning hypertension, irrespective of treatment regimen.

Postnatal blocking of interferon-gamma function prevented atherosclerotic plaque formation in apolipoprotein E-knockout mice.

It is unknown whether interferon-gamma has a positive or negative impact on atherosclerotic plaque formation. Thus, we examined the effects of postnatal interferon-gamma function blocking on plaque formation in apolipoprotein E-knockout (apoEKO) mice by overexpressing a soluble mutant of interferon-gamma receptor (sIFNgammaR), an interferon-gamma inhibitory protein. Mice were fed a Western-type diet from 8 weeks of age. sIFNgammaR or mock plasmid (control) was injected into the thigh muscle at 8 and 10 weeks' age, because serum sIFNgammaR protein was transiently increased with a peak at 2 days after a single sIFNgammaR gene transfer and remained elevated for 2 weeks. At 12 weeks' age, control apoEKO mice showed marked atherosclerotic plaques from the ascending aorta to the aortic arch. The plaques in the aortic root had massive lipid cores and macrophage infiltration with thin fibrous cap and few smooth muscle cells, demonstrating low plaque stability. In contrast, the luminal plaque area was remarkably reduced in sIFNgammaR-treated apoEKO mice. sIFNgammaR treatment not only reduced lipid core areas and macrophage infiltration but also increased smooth muscle cell count and fibrotic area, suggesting improved plaque stability. In controls, interleukin-1beta, monocyte chemoattractant protein-1, and vascular cell adhesion molecules-1 were remarkably upregulated in the aortic wall. These changes were significantly reversed by sIFNgammaR. sIFNgammaR treatment had no effects on serum cholesterol levels. In conclusion, sIFNgammaR treatment prevented plaque formation in apoEKO mice by inhibiting inflammatory changes in the arterial wall. The present study provides insight into a new strategy for preventing atherosclerosis.

Inhibition of progression and stabilization of plaques by postnatal interferon-gamma function blocking in ApoE-knockout mice.

A role of interferon-gamma is suggested in early development of atherosclerosis. However, the role of interferon-gamma in progression and destabilization of advanced atherosclerotic plaques remains unknown. Thus, the aim of this study was to determine whether postnatal inhibition of interferon-gamma signaling could inhibit progression of atherosclerotic plaques and stabilize the lipid- and macrophage-rich advanced plaques. Atherosclerotic plaques were induced in ApoE-knockout (KO) mice by feeding high-fat diet from 8 weeks old (w). Interferon-gamma function was postnatally inhibited by repeated gene transfers of a soluble mutant of interferon-gamma receptors (sIFNgammaR), an interferon-gamma inhibitory protein, into the thigh muscle every 2 weeks. When sIFNgammaR treatment was started at 12 w (atherosclerotic stage), sIFNgammaR not only prevented plaque progression but also stabilized advanced plaques at 16 w: sIFNgammaR decreased accumulations of the lipid and macrophages and increased fibrotic area with more smooth muscle cells. Moreover, sIFNgammaR downregulated expressions of proinflammatory cytokines, chemokines, adhesion molecules, and matrix metalloproteinases but upregulated procollagen type I. sIFNgammaR did not affect serum cholesterol levels. In conclusion, postnatal blocking of interferon-gamma function by sIFNgammaR treatment would be a new strategy to inhibit plaque progression and to stabilize advanced plaques through the antiinflammatory effects.

Inhibition of intrinsic interferon-gamma function prevents neointima formation after balloon injury.

It is still controversial whether intrinsic interferon (IFN)-gamma promotes or attenuates vascular remodeling in hyperproliferative vascular disorders, such as neointima formation after balloon injury. Thus, we investigated whether inhibition of intrinsic IFN-gamma function prevents neointima formation. For this purpose, naked DNA plasmid encoding a soluble mutant of IFN-gamma receptor alpha-subunit (sIFNgammaR; an IFN-gamma inhibitory protein) or mock plasmid was injected into the thigh muscle of male Wistar rats 2 days before balloon injury (day -2). sIFNgammaR gene transfer significantly elevated serum levels of sIFNgammaR protein for 2 weeks. In mock-treated rats, balloon injury induced smooth muscle cell proliferation in the neointima with a peak at day 7 and produced thick neointima at day 14. sIFNgammaR treatment reduced the number of proliferating intimal smooth muscle cells by 50% at day 7 and attenuated neointima formation with a 45% reduction of the intima/media area ratio at day 14. In mock-treated rats, at day 7, balloon injury induced phosphorylation of signal transducer and activator of transcription-1 and upregulations of IFN regulatory factor-1 (a transcription factor mediating IFN-gamma signal). Balloon injury also upregulated the key molecules of neointima formation, such as intercellular adhesion molecule-1 and platelet-derived growth factor beta-receptor. These changes were suppressed by sIFNgammaR treatment. In conclusion, it is suggested that intrinsic IFN-gamma promotes neointima formation probably through IFN regulatory factor-1/intercellular adhesion molecule-1-mediated and platelet-derived growth factor-mediated mechanisms. Thus, inhibition of IFN-gamma signaling may be a new therapeutic target for prevention of neointima formation of hyperproliferative vascular disorders.

Roles of intercellular adhesion molecule-1 in hypertensive cardiac remodeling.

Recently, we have shown that in rats with a suprarenal abdominal aortic constriction (AC), pressure overload induces early perivascular fibro-inflammatory changes (transforming growth factor [TGF]-beta induction and fibroblast proliferation) within the first week after AC and then causes the development of cardiac remodeling (myocyte hypertrophy and reactive myocardial fibrosis) associated with diastolic dysfunction. Intercellular adhesion molecule (ICAM)-1 is implicated in the recruitment of leukocytes, especially macrophages, in various inflammatory situations. Thus, we sought to investigate the causal relation of ICAM-1 to macrophage recruitment and cardiac remodeling in AC rats. In AC rats, immunoreactive ICAM-1 was observed transiently on endothelial cells of the intramyocardial coronary arterioles after day 1, with a peak at day 3, returning to baseline by day 7. Also, ED1+ macrophage accumulation was found in the area adjacent to the arteries expressing ICAM-1. Chronic treatment with an anti-ICAM-1 neutralizing antibody, but not with control IgG, remarkably reduced the accumulations of macrophages and proliferative fibroblasts and inhibited the upregulation of TGF-beta expression. Furthermore, the neutralizing antibody significantly prevented myocardial fibrosis without affecting arterial pressure and left ventricular and myocyte hypertrophy. In conclusion, ICAM-1 expression was induced by pressure overload in the intramyocardial arterioles, and triggered perivascular macrophage accumulation. In pressure-overloaded hearts, a crucial role in ICAM-1-mediated macrophage accumulation was suggested in the development of myocardial fibrosis, through TGF-beta induction and fibroblast activation.

Rho-kinase inhibition reduces neointima formation after vascular injury by enhancing Bax expression and apoptosis.

Recently, we have shown that a specific Rho-kinase inhibitor, Y27632 (R-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide), prevents neointima formation after vascular injury associated with increased terminal deoxynucleotidyl transferase-mediated dUTP nickend labeling (TUNEL)+ smooth muscle cells. Because the mechanism of the action of Y27632 remains unclear, we investigated the expression changes in Bcl family proteins, apoptosis regulators of smooth muscle cells, in the rat carotid artery after balloon injury (BI). Y27632 (BI + Y group) or saline (BI group) was administered peritoneally from Day 1 to Day 14 after BI. Y27632 markedly prevented neointima formation at Day 14. In the BI group, TUNEL+ smooth muscle cells were transiently increased in the neointima, but not in the media, with a peak at Day 7, returning to a lower level by Day 14. Y27632 significantly increased TUNEL+ smooth muscle cells at Days 7 and 14. Smooth muscle cell apoptosis was confirmed by electron microscopic examination. At Day 14, although proapoptotic Bax was slightly, but not significantly, increased in the BI group, it was significantly upregulated in the BI + Y group. Antiapoptotic Bcl-xL was upregulated in the BI group, and the upregulated Bcl-xL was not affected by Y27632. These findings indicate that Rho-kinase inhibition induces neointimal smooth muscle cell apoptosis through Bax upregulation, resulting in reduced neointima formation.

Coexistence of hypercholesterolemia and hypertension impairs adventitial vascularization.

We have shown that adventitial vasa vasorum (AVV) formation is enhanced in hypertensive rat aorta to compensate hypoxia in the thickened media and that hypercholesterolemia impairs angiogenesis in rat ischemic hindlimb. Thus, we examined the effects of coexistence of hypercholesterolemia and hypertension on AVV formation. In Wistar rats, hypercholesterolemia was established by high-cholesterol diet from Day -14 (HC rats), and hypertension was induced by a suprarenal aortic constriction at Day 0 (HT rats). At Day 28, we studied AVV density, adventitial area, and medial thickness in the ascending aorta of control (standard diet+sham operation), HC, HT, and HC+HT rats (n=5/group). In HC rats, although the adventitial area was modestly increased, the AVV density and medial thickness were unchanged versus controls. In addition to medial thickening, marked enlargement of the adventitial area accompanied by increased AVV density was observed in HT rats, compared with controls. HC+HT rats showed lower AVV density, despite larger adventitial area, than HT rats, whereas the medial thickness was similar in HT and HC+HT rats. Immunohistostaining revealed hypoxia-inducible factor-1alpha expression in the media only in HC+HT rats but not in the other 3 groups, suggesting persistent medial hypoxia in HC+HT rats. In conclusion, it is suggested that coexistence of hypercholesterolemia and hypertension impairs AVV formation, resulting in insufficient compensation for hypoxia in the thickened media. Our findings provide an insight into the mechanism of the aggravation of arteriosclerosis when both hypercholesterolemia and hypertension are present.

Hypoxia-inducible factor-1alpha/vascular endothelial growth factor pathway for adventitial vasa vasorum formation in hypertensive rat aorta.

The roles of adventitial vasa vasorum have been highlighted in vascular wall homeostasis. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor in physiological and pathophysiological conditions. However, little is known regarding the changes in adventitial vasa vasorum and the mechanism of the formation in hypertensive arteries. Accordingly, endothelial cell proliferation, adventitial vasa vasorum count, and expression of VEGF signaling axis proteins were examined in the ascending aorta of hypertensive Wistar rats that underwent suprarenal aortic constriction. Hypertension not only induced medial and adventitial thickening but also significantly increased adventitial vasa vasorum count by day 28. Preceding the medial thickening, BrdU(+)-proliferative endothelial cells were observed in the adventitia but not in the media and intima after day 3; they peaked at day 7 and remained modestly increased at day 28. The BrdU(+) endothelial cells showed induction of Ets-1, a transcription factor mediating angiogenic response of VEGF. Furthermore, concomitant expression of VEGF and a hypoxia-inducible transcription factor (HIF-1alpha) was observed in the outer layers of medial smooth muscle cells at day 3 and extended to the middle layers of medial smooth muscle cells at day 7, returning to lower levels by day 28. In conclusion, adventitial vasa vasorum formation was induced by hypertension through the HIF-1alpha/VEGF/Ets-1 pathway during hypertensive remodeling.