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ABSTRACT: Aortic valve stenosis (AS) is the most common form of valvular heart disease in the Western world, affecting ~40% of the population over the age of 80; to date the only established treatment is valve replacement. However, AS progression occurs over many years, and is associated from its earliest stages with increased risk of coronary events. Recent insight into the pathophysiology of AS has included central roles for angiotensin II, for diminished nitric oxide effect at the level of valve endothelium and matrix, and for inflammatory activation/redox stress culminating in activation of pro-calcific stimuli. Despite the presence of atheroma within the stenotic valve, hyperlipidemia per se does not play a critic role in the development of obstructive disease. We review emerging options for pharmacotherapy of AS, including in particular retardation of disease progression. The various clinical evaluations of lipid-reducing therapy have been uniformly unsuccessful in slowing AS progression. However, recent studies in animal models and retrospective evaluations in humans suggest that ACE inhibitors and/or angiotensin receptor blockers may be effective in this regard. Furthermore, agents normally utilized to treat osteoporosis also offer promise in retarding AS. Given the considerable morbidity, mortality and health care costs associated with AS, such therapeutic developments should be expedited.
Pharmacology [?] Therapeutics 04/2012; 135(1):78-93. · 8.56 Impact Factor
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Journal of Internal Medicine 02/2012; 271(6):569-72. · 5.48 Impact Factor
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ABSTRACT: Nitric oxide (NO) is a modulator of left ventricular hypertrophy (LVH) and myocardial relaxation. The impact of NO availability on development of LVH has never been demonstrated in humans. We tested the hypotheses that elevation of asymmetric dimethylarginine (ADMA) concentrations (biochemical marker of decreased NO generation), and impairment of vascular responsiveness to NO donor GTN, would each predict the presence of LVH and associated LV diastolic dysfunction in a normal aging population.
In 74 subjects aged 68±6 years, LV volumes and mass indexed to height(2.7) (LVMI) were calculated from cardiac MRI. Despite the absence of clinically-defined LVH, there was a relationship (r=0.29; p=0.01) between systolic BP and LVMI. Both elevation of ADMA levels to the highest quartile or impairment of GTN responsiveness (determined by applanation tonometry) to the lowest quartile were determinants of LVMI independent of systolic BP (p=0.01 and p=0.03, respectively). Filling pressure (E/E' ratio from echocardiography) was increased in patients with impaired vascular NO responsiveness (p<0.05) irrespective of LVMI. ADMA remained a significant determinant of LVMI on multivariate analysis.
These data imply that NO bioavailability within the myocardium modulates earliest stages of LVH development and facilitates development of diastolic dysfunction at a given LV mass.
Nitric Oxide 06/2011; 25(1):41-6. · 3.55 Impact Factor
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D T M Ngo,
W P Chan,
S Rajendran,
T Heresztyn,
A Amarasekera, A L Sverdlov,
P D O'Loughlin,
H A Morris,
Y Y Chirkov,
R J Norman,
J D Horowitz
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ABSTRACT: Polycystic ovary syndrome (PCOS) is associated with incremental risk of atherosclerosis and possibly of cardiovascular events. Insulin resistance (IR) occurs frequently in PCOS subjects, which might be one of the mechanisms involved in engendering such risk. We sought to evaluate whether the impact of other factors potentially associated both with PCOS and with IR might differentially modulate degree of IR in women with and without PCOS.
We measured body mass index (BMI), hs-CRP, plasma concentrations of asymmetric dimethylarginine (ADMA), vitamin D (25(OH)D3) levels and platelet responsiveness to nitric oxide donor sodium nitroprusside (NO responsiveness) in 47 young women (n=27 with PCOS and n=20 weight-matched controls) without metabolic syndrome, hypertension or overt cardiovascular disease. We performed univariate and multivariate regression analyses to establish correlates of the quantitative insulin-sensitivity check index (QUICKI), as a marker of IR. On univariate analysis, plasma 25(OH)D3 levels and low NO responsiveness tended to be direct correlates with QUICKI in the entire subject group. BMI, hs-CRP, and ADMA levels were significant inverse correlates of QUICKI in PCOS subjects, but not in subjects without PCOS. On multivariate analysis, NO responsiveness, and 25(OH)D3 levels, but not PCOS per se were significant correlates of QUICKI.
In the entire cohort of young women, low NO responsiveness and vitamin D deficiency are associated with low QUICKI, while elevated ADMA, inflammatory activation and obesity are selectively associated with low QUICKI in PCOS subjects; this may contribute to the increased cardiovascular risk associated with this syndrome.
Nitric Oxide 06/2011; 25(3):326-30. · 3.55 Impact Factor
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D.T.M. Ngo,
W.P. Chan,
S. Rajendran,
T. Heresztyn,
A. Amarasekera, A.L. Sverdlov,
P.D. O’Loughlin,
H.A. Morris,
Y.Y. Chirkov,
R.J. Norman,
J.D. Horowitz
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ABSTRACT: Background
Polycystic ovary syndrome (PCOS) is associated with incremental risk of atherosclerosis and possibly of cardiovascular events. Insulin resistance (IR) occurs frequently in PCOS subjects, which might be one of the mechanisms involved in engendering such risk. We sought to evaluate whether the impact of other factors potentially associated both with PCOS and with IR might differentially modulate degree of IR in women with and without PCOS.Methods and resultsWe measured body mass index (BMI), hs-CRP, plasma concentrations of asymmetric dimethylarginine (ADMA), vitamin D (25(OH)D3) levels and platelet responsiveness to nitric oxide donor sodium nitroprusside (NO responsiveness) in 47 young women (n = 27 with PCOS and n = 20 weight-matched controls) without metabolic syndrome, hypertension or overt cardiovascular disease. We performed univariate and multivariate regression analyses to establish correlates of the quantitative insulin-sensitivity check index (QUICKI), as a marker of IR.On univariate analysis, plasma 25(OH)D3 levels and low NO responsiveness tended to be direct correlates with QUICKI in the entire subject group. BMI, hs-CRP, and ADMA levels were significant inverse correlates of QUICKI in PCOS subjects, but not in subjects without PCOS. On multivariate analysis, NO responsiveness, and 25(OH)D3 levels, but not PCOS per se were significant correlates of QUICKI.Conclusions
In the entire cohort of young women, low NO responsiveness and vitamin D deficiency are associated with low QUICKI, while elevated ADMA, inflammatory activation and obesity are selectively associated with low QUICKI in PCOS subjects; this may contribute to the increased cardiovascular risk associated with this syndrome.Highlights► Polycystic ovarian syndrome (PCOS) is associated with endothelial dysfunction and platelet NO resistance. ► However, PCOS is also associated with insulin resistance (IR) and obesity. ► In these young PCOS subjects and controls, platelet NO resistance and low plasma vitamin D levels correlated with IR. ► However, in PCOS subjects only, high BMI, elevated CRP and elevation of ADMA concentrations were correlates of IR. ► These differential relationships may contribute to incremental atherogenic risk in PCOS.
Nitric Oxide. 25(3):326-330.
