(1/12919) Myocardial osteopontin expression coincides with the development of heart failure.
To identify genes that are differentially expressed during the transition from compensated hypertrophy to failure, myocardial mRNA from spontaneously hypertensive rats (SHR) with heart failure (SHR-F) was compared with that from age-matched SHR with compensated hypertrophy (SHR-NF) and normotensive Wistar-Kyoto rats (WKY) by differential display reverse transcriptase-polymerase chain reaction. Characterization of a transcript differentially expressed in SHR-F yielded a cDNA with homology to the extracellular matrix protein osteopontin. Northern analysis showed low levels of osteopontin mRNA in left ventricular myocardium from WKY and SHR-NF but a markedly increased (approximately 10-fold) level in SHR-F. In myocardium from WKY and SHR-NF, in situ hybridization showed only scant osteopontin mRNA, primarily in arteriolar cells. In SHR-F, in situ hybridization revealed abundant expression of osteopontin mRNA, primarily in nonmyocytes in the interstitial and perivascular space. Similar findings for osteopontin protein were observed in the midwall region of myocardium from the SHR-F group. Consistent with the findings in SHR, osteopontin mRNA was minimally increased (approximately 1.9-fold) in left ventricular myocardium from nonfailing aortic-banded rats with pressure-overload hypertrophy but was markedly increased (approximately 8-fold) in banded rats with failure. Treatment with captopril starting before or after the onset of failure in the SHR reduced the increase in left ventricular osteopontin mRNA levels. Thus, osteopontin expression is markedly increased in the heart coincident with the development of heart failure. The source of osteopontin in SHR-F is primarily nonmyocytes, and its induction is inhibited by an angiotensin-converting enzyme inhibitor, suggesting a role for angiotensin II. Given the known biological activities of osteopontin, including cell adhesion and regulation of inducible nitric oxide synthase gene expression, these data suggest that it could play a role in the pathophysiology of heart failure. (+info)
(2/12919) Effects of amlodipine on sympathetic nerve traffic and baroreflex control of circulation in heart failure.
Short-acting calcium antagonists exert a sympathoexcitation that in heart failure further enhances an already elevated sympathetic activity. Whether this is also the case for long-acting formulations is not yet established, despite the prognostic importance of sympathetic activation in heart failure. It is also undetermined whether in this condition long-acting calcium antagonists favorably affect a mechanism potentially responsible for the sympathetic activation, ie, the baroreflex impairment. In 28 heart failure patients (NYHA functional class II) under conventional treatment we measured plasma norepinephrine and efferent postganglionic muscle sympathetic nerve activity (microneurography) at rest and during arterial baroreceptor stimulation and deactivation induced by stepwise intravenous infusions of phenylephrine and nitroprusside, respectively. Measurements were performed at baseline and after 8 weeks of daily oral amlodipine administration (10 mg/d, 14 patients) or before and after an 8-week period without calcium antagonist administration (14 patients). Amlodipine caused a small and insignificant blood pressure reduction. Heart rate, left ventricular ejection fraction, and plasma renin and aldosterone concentrations were not affected. This was the case also for plasma norepinephrine (from 2.43+/-0.41 to 2.50+/-0.34 nmol/L, mean+/-SEM), muscle sympathetic nerve activity (from 54.4+/-5.9 to 51.0+/-4.3 bursts/min), and arterial baroreflex responses. No change in the above-mentioned variables was seen in the control group. Thus, in mild heart failure amlodipine treatment does not adversely affect sympathetic activity and baroreflex control of the heart and sympathetic tone. This implies that in this condition long-acting calcium antagonists can be administered without untoward neurohumoral effects anytime conventional treatment needs to be complemented by drugs causing additional vasodilatation. (+info)
(3/12919) Gender-related differences in myocyte remodeling in progression to heart failure.
Gender-related differences responsible for the better prognosis of females with heart failure have not been clearly established. To address this issue, we investigated potential gender-related differences in myocyte remodeling in spontaneously hypertensive heart failure rats. Echocardiograms and myocyte growth were compared between males and females at compensated (2, 4, and 6 months) and decompensated (18 months in males and 24 months in females) stages of cardiac hypertrophy. Although left ventricular diastolic dimensions did not differ significantly between failing male and female rats, fractional shortening declined significantly only in failing males. Myocyte cross-sectional area did not change after 4 months of age in both genders, which is likely to be responsible for the absence of a change in left ventricular wall thickness during the progression to heart failure. Myocyte volume and cross-sectional area were significantly larger in males than females at 2, 4, and 6 months of age, although there were no significant differences at the failing stage. Reduced adaptive hypertrophic reserve was observed in males, which is likely to contribute to the higher morbidity and mortality of males with chronic heart failure. (+info)
(4/12919) Hereditary juvenile haemochromatosis: a genetically heterogeneous life-threatening iron-storage disease.
Juvenile haemochromatosis is a rare inborn error of iron metabolism with clinical manifestations before 30 years of age. Unlike adult haemochromatosis which principally affects men, juvenile haemochromatosis affects the sexes equally; it causes early endocrine failure, dilated cardiomyopathy and joint disease. We report four patients (two of each sex) from three pedigrees affected by juvenile haemochromatosis with a mean onset at 22 years (range 14-30). All had endocrine deficiency with postpubertal gonadal failure secondary to pituitary disease; two suffered near-fatal cardiomyopathy with heart failure. Mean time to diagnosis from the first clinical signs of disease was 9.8 years (range 0.5-20) but general health and parameters of iron storage responded favourably to iron-depletion therapy. A 24-year-old man listed for heart transplantation because of cardiomyopathy [left ventricular (LV) ejection fraction 16%] responded to intravenous iron chelation with desferrioxamine combined with phlebotomy (ejection fraction 31%). A 27-year-old woman with subacute biventricular heart failure refractory to medication required orthotopic cardiac transplantation before the diagnosis was established (LV ejection fraction 25%). Genetic studies showed that these two patients with cardiomyopathy from unrelated families were heterozygous for the HFE 845G-->A (C282Y) mutation and wild-type at the H63D locus: complete sequencing of the intron-exon boundaries and entire coding sequence of the HFE gene failed to identify additional lesions. Two siblings in a pedigree without cardiomyopathy were wild-type at the HFE C282Y locus; although the brother harboured a single copy of the 187C-->G (H63D) allele, segregation analysis showed that in neither sibling was the iron-storage disease linked to MHC Class I markers on chromosome 6p. Juvenile haemochromatosis is thus a genetically heterogenous disorder distinct from the common adult variant. (+info)
(5/12919) Sympathetic nerve alterations assessed with 123I-MIBG in the failing human heart.
Norepinephrine (NE) reuptake function is impaired in heart failure and this may participate in myocyte hyperstimulation by the neurotransmitter. This alteration can be assessed by 123I-metaiodobenzylguanidine (MIBG) scintigraphy. METHODS: To determine whether the impairment of neuronal NE reuptake was reversible after metoprolol therapy, we studied 18 patients (43+/-7 y) with idiopathic dilated cardiomyopathy who were stabilized at least for 3 mo with captopril and diuretics. Patients underwent, before and after 6 mo of therapy with metoprolol, measurements of radionuclide left ventricular ejection fraction (LVEF), maximal oxygen consumption and plasma NE concentration. The cardiac adrenergic innervation function was scintigraphically assessed with MIBG uptake and release measurements on the planar images obtained 20 min and 4 h after tracer injection. To evaluate whether metoprolol had a direct interaction with cardiac MIBG uptake and release, six normal subjects were studied before and after a 1-mo metoprolol intake. RESULTS: In controls, neither cardiac MIBG uptake and release nor circulating NE concentration changed after the 1-mo metoprolol intake. Conversely, after a 6-mo therapy with metoprolol, patients showed increased cardiac MIBG uptake (129%+/-10% versus 138%+/-17%; P = 0.009), unchanged cardiac MIBG release and decreased plasma NE concentration (0.930+/-412 versus 0.721+/-0.370 ng/mL; P = 0.02). In parallel, patients showed improved New York Heart Association class (2.44+/-0.51 versus 2.05+/-0.23; P = 0.004) and increased LVEF (20%+/-8% versus 27%+/-8%; P = 0.0005), whereas maximal oxygen uptake remained unchanged. CONCLUSION: Thus, a parallel improvement of myocardial NE reuptake and of hemodynamics was observed after a 6-mo metoprolol therapy, suggesting that such agents may be beneficial in heart failure by directly protecting the myocardium against excessive NE stimulation. (+info)
(6/12919) Premature morbidity from cardiovascular and cerebrovascular diseases in women with systemic lupus erythematosus.
OBJECTIVE: To determine rates of morbidity due to cardiovascular and cerebrovascular diseases among women with systemic lupus erythematosus (SLE). METHODS: I used the California Hospital Discharge Database, which contains information on all discharges from acute care hospitals in California, to identify women with SLE who had been hospitalized for treatment of either acute myocardial infarction (AMI), congestive heart failure (CHF), or cerebrovascular accident (CVA) from 1991 to 1994. I compared the proportions of hospitalizations for each cause among women with SLE with those in a group of women without SLE, for 3 age strata (18-44 years, 45-64 years, and > or =65 years). RESULTS: Compared with young women without SLE, young women with SLE were 2.27 times more likely to be hospitalized because of AMI (95% confidence interval [95% CI] 1.08-3.46), 3.80 times more likely to be hospitalized because of CHF (95% CI 2.41-5.19), and 2.05 times more likely to be hospitalized because of CVA (95% CI 1.17-2.93). Among middle-aged women with SLE, the frequencies of hospitalization for AMI and CVA did not differ from those of the comparison group, but the risk of hospitalization for CHF was higher (odds ratio [OR] 1.39, 95% CI 1.05-1.73). Among elderly women with SLE, the risk of hospitalization for AMI was significantly lower (OR 0.70, 95% CI 0.51-0.89), the risk of hospitalization for CHF was higher (OR 1.25, 95% CI 1.01-1.49), and the risk of hospitalization for CVA was not significantly different from those in the comparison group. CONCLUSION: Young women with SLE are at substantially increased risk of AMI, CHF, and CVA. The relative odds of these conditions decrease with age among women with SLE. (+info)
(7/12919) QT dispersion in patients with chronic heart failure: beta blockers are associated with a reduction in QT dispersion.
OBJECTIVE: To compare QT dispersion in patients with impaired left ventricular systolic function and in matched control patients with normal left ventricular systolic function. DESIGN: A retrospective, case-control study with controls matched 4:1 for age, sex, previous myocardial infarction, and diuretic and beta blocker treatment. SETTING: A regional cardiology centre and a university teaching hospital. PATIENTS: 25 patients with impaired left ventricular systolic function and 100 patients with normal left ventricular systolic function. MAIN OUTCOME MEASURES: QT and QTc dispersion measured by three methods: the difference between maximum and minimum QT and QTc intervals, the standard deviation of QT and QTc intervals, and the "lead adjusted" QT and QTc dispersion. RESULTS: All measures of QT/QTc dispersion were closely interrelated (r values 0.86 to 0.99; all p < 0.001). All measures of QT and QTc dispersion were significantly increased in the patients with impaired left ventricular systolic function v controls (p < 0.001): 71.9 (6.5) (mean (SEM)) v 46.9 (1.7) ms for QT dispersion, and 83.6 (7.6) v 54.3 (2.1) ms(-1-2) for QTc dispersion. All six dispersion parameters were reduced in patients taking beta blockers (p < 0.05), regardless of whether left ventricular function was normal or impaired-by 9.4 (4.6) ms for QT dispersion (p < 0.05) and by 13.8 (6. 5) ms(-1-2) for QTc dispersion (p = 0.01). CONCLUSIONS: QT and QTc dispersion are increased in patients with systolic heart failure in comparison with matched controls, regardless of the method of measurement and independently of possible confounding factors. beta Blockers are associated with a reduction in both QT and QTc dispersion, raising the possibility that a reduction in dispersion of ventricular repolarisation may be an important antiarrhythmic mechanism of beta blockade. (+info)
(8/12919) Expression of skeletal muscle sarcoplasmic reticulum calcium-ATPase is reduced in rats with postinfarction heart failure.
OBJECTIVE: To determine whether heart failure in rats is associated with altered expression of the skeletal muscle sarcoplasmic reticulum Ca2+-ATPase (SERCA). METHODS: SERCA protein and mRNA were examined in the soleus muscles of eight female rats with heart failure induced by coronary artery ligation, six weeks after the procedure (mean (SEM) left ventricular end diastolic pressure 20.4 (2.2) mm Hg) and in six sham operated controls by western and northern analyses, respectively. RESULTS: SERCA-2a isoform protein was reduced by 16% (112 000 (4000) v 134 000 (2000) arbitrary units, p < 0.001), and SERCA-2a messenger RNA was reduced by 59% (0.24 (0. 06) v 0.58 (0.02) arbitrary units, p < 0.001). Although rats with heart failure had smaller muscles (0.54 mg/g v 0.66 mg/g body weight), no difference in locomotor activity was observed. CONCLUSIONS: These results may explain the previously documented abnormalities in calcium handling in skeletal muscle from animals with the same model of congestive heart failure, and could be responsible for the accelerated muscle fatigue characteristic of patients with heart failure. (+info)