Respiratory muscle dysfunction in congestive heart failure--the role of pulmonary hypertension.

BACKGROUND: Inspiratory muscle weakness has been described in patients with congestive heart failure (CHF), and only recently in patients with idiopathic pulmonary arterial hypertension. However, the relationship between pulmonary hemodynamics and respiratory muscle function has not been investigated in patients with CHF. METHODS AND RESULTS: In two tertial referral centers for CHF patients, 532 consecutive CHF patients (159 female, age 59 ± 12 years, NYHA I-IV) were studied by right heart catheterization, maximal inspiratory mouth occlusion pressure (Pi(max)) and pressure 0.1s after beginning of inspiration during tidal breathing at rest (P(0.1)). There was a significant correlation between Pi(max) and mean pulmonary artery pressure (PAPm) (r=-0.65, p=0.0023), mean pulmonary capillary wedge pressure (PCWPm) (r=-0.56; p=0.0018), PVR (r=-0.73; p=0.0031), and cardiac output (r=0.51; p=0.0022). Moreover, the ratio P(0.1)/Pi(max) showed a linear correlation with PAPm (r=0.54; p=0.0019), and with TPG (r=0.64; p=0.0014) respectively. Vital capacity was reduced in relation to increased PAPm (r=-0.54; p=0.0029). Pi(max) and P(0.1)/Pi(max) were independent from VC. CONCLUSIONS: This study provides the first evidence of a close relation between inspiratory muscle dysfunction, increased ventilatory drive and pulmonary hypertension in a large patient cohort with CHF. Pi(max) and P(0.1) can easily be measured in clinical routine and might become an additional parameter for the non-invasive monitoring of the hemodynamic severity of disease.

Pulmonary hypertension: Hemodynamic evaluation. Updated Recommendations of the Cologne Consensus Conference 2011.

The 2009 European Guidelines on Diagnosis and Treatment of Pulmonary Hypertension have been adopted for Germany. The guidelines contain detailed recommendations for the diagnosis of pulmonary hypertension. However, the practical implementation of the European Guidelines in Germany requires the consideration of several country-specific issues and already existing novel data. This requires a detailed commentary to the guidelines, and in some aspects an update already appears necessary. In June 2010, a Consensus Conference organized by the PH working groups of the German Society of Cardiology (DGK), the German Society of Respiratory Medicine (DGP) and the German Society of Pediatric Cardiology (DGPK) was held in Cologne, Germany. This conference aimed to solve practical and controversial issues surrounding the implementation of the European Guidelines in Germany. To this end, a number of working groups was initiated, one of which was specifically dedicated to the invasive hemodynamic evaluation of pulmonary hypertension. This manuscript describes in detail the results and recommendations of the working group which were last updated in October 2011.

Expression of toll-like receptor 4, tumor necrosis factor- alpha, matrix metalloproteinase-9 and effects of benazepril in patients with acute coronary syndromes.

OBJECTIVES: The study aims to explore the relationship between expressions of toll-like receptor 4 (TLR4) on peripheral blood monocytes, serum tumor necrosis factor-alpha (TNF-α) and matrix metalloproteinase-9 (MMP-9) in patients with acute coronary syndromes(ACS), and to investigate the possible mechanisms of Benazepril stabilizing atherosclerosis plaques. METHODS: 70 patients selected were randomly divided into Benazepril treatment group (35 patients) and regular treatment group (35 patients). Meanwhile, Stable angina pectoris (SAP) group of 32 patients and control group of 22 patients were also set up. With the help of flow-cytometry, expressions of TLR4 on peripheral blood monocytes of the four groups were analyzed and compared to show differences, correlations and changes of the above mentioned indicators. The concentration of TNF-α and MMP-9 in serum were measured by enzyme linked immunosorbent assay (ELISA). RESULTS: (1) Expressions of TLR4, levels of TNF-α and MMP-9 were increased and the rate was rising from the control group, to SAP group and then to ACS group. All these indicators in ACS group are significantly higher than those in other groups (P < 0.05). (ACS versus SAP, control; all (P < 0.05). (2) Multi-linear regression analysis indicates that there was a positive correlation between the expression level of TLR4 and serum levels of TNF-α and MMP-9 in patients with ACS (P < 0.01). (3) There is no significant differences between the expression level of TLR4 and serum levels of TNF-α and MMP-9 in Benazepril treatment group and regular treatment group before treatment (P > 0.05) while they all fell after treatment (P < 0.05). In addition, all the indicators decreased more greatly than the regular treatment group. CONCLUSIONS: TLR4 on peripheral blood monocytes and serum TNF-α and MMP-9 in patients with coronary arteriosclerosis disease may be effective markers of the vulnerable plaque. Benazepril can inhibit over-expression of TLR4 and reduce serum levels of TNF-α and MMP-9, thus stabilize the vulnerable plaques and improve the condition of the patients with ACS.

Lung endothelial dysfunction in congestive heart failure: role of impaired Ca2+ signaling and cytoskeletal reorganization.

RATIONALE: Congestive heart failure (CHF) frequently results in remodeling and increased tone of pulmonary resistance vessels. This adaptive response, which aggravates pulmonary hypertension and thus, promotes right ventricular failure, has been attributed to lung endothelial dysfunction. OBJECTIVE: We applied real-time fluorescence imaging to identify endothelial dysfunction and underlying molecular mechanisms in an experimental model of CHF induced by supracoronary aortic banding in rats. METHODS AND RESULTS: Endothelial dysfunction was evident in lungs of CHF rats as impaired endothelium-dependent vasodilation and lack of endothelial NO synthesis in response to mechanical stress, acetylcholine, or histamine. This effect was not attributable to downregulation of endothelial NO synthase. Imaging of the cytosolic Ca(2+) concentration ([Ca(2+)](i)) revealed a singular impairment of endothelial [Ca(2+)](i) homeostasis and signaling characterized by a lack of [Ca(2+)](i) oscillations and deficient or attenuated [Ca(2+)](i) responses to mechanical stress, histamine, acetylcholine, or thapsigargin. Reconstitution of a [Ca(2+)](i) signal by ionophore treatment restored endothelial NO production, but lack of endothelial responsiveness was not primarily attributable to downregulation of Ca(2+) influx channels in CHF. Rather, we identified a massive remodeling of the endothelial cytoskeleton in the form of an increased expression of beta-actin and F-actin formation which contributed critically to endothelial dysfunction in CHF because cytoskeletal disruption by cytochalasin D largely reconstituted endothelial [Ca(2+)](i) signaling and NO production. CONCLUSIONS: Our findings characterize a unique scenario of endothelial dysfunction in CHF that is caused by a singular impairment of [Ca(2+)](i) signaling, and identify cytoskeletal reorganization as a major regulator of endothelial signaling and function.

Long-term therapy with inhaled iloprost in patients with pulmonary hypertension.

AIMS: To investigate the long-term safety of inhaled iloprost in patients with pulmonary hypertension (pH), including idiopathic PAH (IPAH group) and other forms of pulmonary hypertension (PHother). METHODS AND RESULTS: Sixty-three patients (IPAH group, n=40, PHother n=23) were enrolled to receive inhaled iloprost either from baseline or after 3 months in a prospective, open-label 2-year study. Iloprost was inhaled 6-9 times daily with a night pause employing a jet nebulizer delivering an inhaled single dose of 4microg at the mouthpiece. In the case of side effects the single dose was reduced to 2microg. Sixty patients received at least 1 dose of inhaled iloprost. Thirty-six patients completed at least 630 days of therapy (25 IPAH, 11 PHother), 19 patients dropped out prematurely and 8 patients died (3 IPAH, 5 PHother). There were no drug-induced toxicities and only mild to moderate side effects. The most common side effects were coughing and flushing. Two-year survival was estimated at 85% (IPAH group 91%, PHother 78%). A modified analysis was performed to correct for differential drop-out. It included follow-up data from the premature discontinuations and revealed a 2-year survival of 87% [95% CI, 76%-98%] in the IPAH group while the predicted survival was 63%. The iloprost dose increased by 16% over 2 years. CONCLUSION: Inhaled iloprost is well tolerated as long-term therapy and no substantial dose increase is required. Although uncontrolled, the data suggest a long-term clinical benefit from continued therapy with inhaled iloprost.

Endothelin receptor antagonist and airway dysfunction in pulmonary arterial hypertension.

BACKGROUND: In idiopathic pulmonary arterial hypertension (IPAH), peripheral airway obstruction is frequent. This is partially attributed to the mediator dysbalance, particularly an excess of endothelin-1 (ET-1), to increased pulmonary vascular and airway tonus and to local inflammation. Bosentan (ET-1 receptor antagonist) improves pulmonary hemodynamics, exercise limitation, and disease severity in IPAH. We hypothesized that bosentan might affect airway obstruction. METHODS: In 32 IPAH-patients (19 female, WHO functional class II (n = 10), III (n = 22); (data presented as mean +/- standard deviation) pulmonary vascular resistance (11 +/- 5 Wood units), lung function, 6 minute walk test (6-MWT; 364 +/- 363.7 (range 179.0-627.0) m), systolic pulmonary artery pressure, sPAP, 79 +/- 19 mmHg), and NT-proBNP serum levels (1427 +/- 2162.7 (range 59.3-10342.0) ng/L) were measured at baseline, after 3 and 12 months of oral bosentan (125 mg twice per day). RESULTS AND DISCUSSION: At baseline, maximal expiratory flow at 50 and 25% vital capacity were reduced to 65 +/- 25 and 45 +/- 24% predicted. Total lung capacity was 95.6 +/- 12.5% predicted and residual volume was 109 +/- 21.4% predicted. During 3 and 12 months of treatment, 6-MWT increased by 32 +/- 19 and 53 +/- 69 m, respectively; p < 0.01; whereas sPAP decreased by 7 +/- 14 and 10 +/- 19 mmHg, respectively; p < 0.05. NT-proBNP serum levels tended to be reduced by 123 +/- 327 and by 529 +/- 1942 ng/L; p = 0.11). There was no difference in expiratory flows or lung volumes during 3 and 12 months. CONCLUSION: This study gives first evidence in IPAH, that during long-term bosentan, improvement of hemodynamics, functional parameters or serum biomarker occur independently from persisting peripheral airway obstruction.

Skeletal muscle dysfunction in patients with idiopathic pulmonary arterial hypertension.

Dyspnea and exercise limitation are common in patients with idiopathic pulmonary arterial hypertension (IPAH). Recently, a reduction in inspiratory and expiratory muscle strength has been observed in IPAH. However, it has not been investigated whether this respiratory muscle weakness might be part of a general muscle dysfunction as observed in congestive left heart failure. Therefore, in 24 consecutive IPAH patients (16 female; age 58.7+/-16.2; WHO class II-III; systolic pulmonary artery pressure during echocardiography at rest (sPAP) 65.0+/-20.6 mmHg, and 6-min-walk test (6-MWT) 473.6+/-127.7 m), the maximal isometric forearm muscle strength (best of three hand grip manoeuvres), maximal inspiratory and expiratory mouth occlusion pressures (Pimax, Pemax) were prospectively evaluated. The isometric forearm muscle strength was significantly lower in IPAH patients (281.7+/-102.6N) than in matched 24 healthy controls (397.1+/-116.8 N; p=0.03). In IPAH patients, there was a correlation between maximal isometric forearm muscle strength and 6-MWT (r=0.67; p=0.0007) and both, Pimax (r=0.69; p=0.0003) and Pemax (r=0.63; p=0.01), respectively. There was no correlation between forearm muscle strength and sPAP (r=0.30; p=0.16). The present skeletal muscle dysfunction is a novel finding in patients with IPAH. The correlation with respiratory muscle dysfunction and severity of disease might indicate a generalised "myopathy" in IPAH.

Effect of inhaled iloprost during off-medication time in patients with pulmonary arterial hypertension.

BACKGROUND: Iloprost is a stable prostacyclin analogue that is associated with a longer duration of vasodilatation and has been approved for inhalative use with 6 or 9 inhalations during the daytime and a night pause. It is not known if during the night pause rebound pulmonary hypertension occurs. The aim of this study was to assess the hemodynamics in iloprost-treated patients during the daytime and at night. METHODS: We enrolled 5 adult patients (aged 45 +/- 10 years) with idiopathic pulmonary arterial hypertension (IPAH) and chronic inhaled iloprost therapy for at least 12 months. Further medication remained unchanged during the study period. Hemodynamics were monitored by right heart catheterization. RESULTS: After 30-60 min of nebulized iloprost, mean pulmonary arterial pressures (PAP) decreased from 68 +/- 15 to 51 +/- 18 mm Hg (p = 0.004). After 6 h off-medication sleeping time, mean PAP initially increased until 2 a.m. and decreased subsequently until wake-up time at 6 a.m. Mean PAP, cardiac index and pulmonary vascular resistance at night were not significantly different from the values during the day. CONCLUSIONS: In this study, patients with IPAH and chronic nebulized iloprost therapy did not reveal a rebound pulmonary hypertension during off-medication sleeping time.

Regulation of cardiac inwardly rectifying potassium current IK1 and Kir2.x channels by endothelin-1.

To elucidate the ionic mechanism of endothelin-1 (ET-1)-induced focal ventricular tachyarrhythmias, the regulation of I(K1) and its main molecular correlates, Kir2.1, Kir2.2 and Kir2.3 channels, by ET-1 was investigated. Native I(K1) in human atrial cardiomyocytes was studied with whole-cell patch clamp. Human endothelin receptors were coexpressed with human Kir2.1, Kir2.2 and Kir2.3 channels in Xenopus oocytes. Currents were measured with a two-microelectrode voltage clamp. In human cardiomyocytes, ET-1 induced a marked inhibition of I(K1) that could be suppressed by the protein kinase C (PKC) inhibitor staurosporine. To investigate the molecular mechanisms underlying this regulation, we studied the coupling of ET(A) receptors to homomeric and heteromeric Kir2.1, Kir2.2 and Kir2.3 channels in the Xenopus oocyte expression system. ET(A) receptors coupled functionally to Kir2.2 and Kir2.3 channels but not to Kir2.1 channels. In Kir2.2 channels lacking functional PKC phosphorylation sites, the inhibitory effect was abolished. The inhibition of Kir2.3 currents could be suppressed by the PKC inhibitors staurosporine and chelerythrine. The coupling of ET(A) receptors to heteromeric Kir2.1/Kir2.2 and Kir2.2/Kir2.3 channels resulted in a strong inhibition of currents comparable with the effect observed in Kir2.2 homomers. Surprisingly, in heteromeric Kir2.1/Kir2.3 channels, no effect was observed. ET-1 inhibits human cardiac I(K1) current via a PKC-mediated phosphorylation of Kir2.2 channel subunits and additional regulatory effects on Kir2.3 channels. This mechanism may contribute to the intrinsic arrhythmogenic potential of ET-1.

Adult patients with congenital heart disease and pulmonary arterial hypertension: first open prospective multicenter study of bosentan therapy.

BACKGROUND: Endothelin receptor antagonism has been introduced as an effective oral therapy of patients with idiopathic pulmonary arterial hypertension. In view of the pathophysiologic and histologic similarities between idiopathic pulmonary arterial hypertension and pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD), there is a rationale for treating these patients with the oral dual (ET(A)/ET(B)) endothelin receptor antagonist bosentan. METHODS: Thirty-three patients with PAH-CHD (43 +/- 14 years, 23 with Eisenmenger syndrome) were treated with bosentan for a mean of 2.1 +/- 0.5 years. Efficacy was assessed by a panel of tests, including New York Heart Association functional class, 6-minute walking distance, and echocardiographic and hemodynamic parameters. RESULTS: Mean 6-minute walking distance increased from 362 +/- 105 to 434 +/- 68 m (P = .001). New York Heart Association class also improved significantly (3.1 to 2.4, P = .0001). This was associated with slight trends in improvements of transcutaneous oxygen saturation (86% +/- 7% to 88% +/- 7%, P = .13) and maximum oxygen uptake (13.2 +/- 4.0 to 14.9 +/- 2.5, P = .18). Right ventricular systolic pressure measured by echocardiographic decreased from 111 +/- 32 to 106 +/- 22 mm Hg (P = .001). Bosentan treatment was well tolerated by all patients. CONCLUSIONS: Long-term bosentan treatment in adult patients with PAH-CHD was well tolerated and improved functional status as well as exercise capacity. These findings have to be corroborated by controlled studies that are presently ongoing.

Value of high spatial and high temporal resolution magnetic resonance angiography for differentiation between idiopathic and thromboembolic pulmonary hypertension: initial results.

Differentiation between different forms of pulmonary hypertension (PH) is essential for correct disease management. The goal of this study was to elucidate the clinical impact of high spatial resolution MR angiography (SR-MRA) and time-resolved MRA (TR-MRA) to differentiate between patients with chronic thromboembolic PH (CTEPH) and idiopathic pulmonary arterial hypertension (IPAH). Ten PH patients and five volunteers were examined. Twenty TR-MRA data sets (TA 1.5 s) and SR-MRA (TA 23 s) were acquired. TR-MRA data sets were subtracted as angiography and perfusion images. Evaluation comprised analysis of vascular pathologies on a segmental basis, detection of perfusion defects, and bronchial arteries by two readers in consensus. Technical evaluation comprised evaluation of image quality, signal-to-noise ratio (SNR) measurements, and contrast-media passage time. Visualization of the pulmonary arteries was possible down to a subsegmental (SR-MRA) and to a segmental (TR-MRA) level. SR-MRA outperformed TR-MRA in direct visualization of intravascular changes. Patients with IPAH predominantly showed tortuous pulmonary arteries while in CTEPH wall irregularities and abnormal proximal-to-distal tapering was found. Perfusion images showed a diffuse pattern in IPAH and focal defects in CTEPH. TR-MRA and SR-MRA resulted in the same final diagnosis. Both MRA techniques allowed for differentiation between IPAH and CTEPH. Therefore, TR-MRA can be used in the clinical setting, especially in dyspneic patients.

[Suspicion of COPD--development of an algorithm for stepwise diagnosis in primary care]. / Verdacht auf COPD--Entwicklung eines Algorithmus zur Stufendiagnostik in der Hausarztpraxis.

The implementation of the disease management programme (DMP) for asthma and COPD in the German health system in 2005 requires an optimal and evidence-based work-up of patients by general practitioners in routine daily practice. The German and international guidelines for COPD do not provide recommendations for a stepwise diagnostic work-up in primary care. Therefore, an evidence-based algorithm was developed for a stepwise diagnosis of COPD and its different stages in general practice, based on national and foreign guidelines that provide specific advice on diagnostic procedures.

Are ICD-10 codes appropriate for performance assessment in asthma and COPD in general practice? Results of a cross sectional observational study.

BACKGROUND: The increasing prevalence and impact of obstructive lung diseases and new insights, reflected in clinical guidelines, have led to concerns about the diagnosis and therapy of asthma and COPD in primary care. In Germany diagnoses written in medical records are used for reimbursement, which may influence physicians' documentation behaviour. For that reason it is unclear to what respect ICD-10 codes reflect the real problems of the patients in general practice. The aim of this study was to assess the appropriateness of the recorded diagnoses and to determine what diagnostic information is used to guide medical treatment. METHODS: All patients with lower airway symptoms (n = 857) who had attended six general practices between January and June 2003 were included into this cross sectional observational study. Patients were selected from the computerised medical record systems, focusing on ICD-10-codes concerning lower airway diseases (J20-J22, J40-J47, J98 and R05). The performed diagnostic procedures and actual medication for each identified patient were extracted manually. Then we examined the associations between recorded diagnoses, diagnostic procedures and prescribed treatment for asthma and COPD in general practice. RESULTS: Spirometry was used in 30% of the patients with a recorded diagnosis of asthma and in 58% of the patients with a recorded diagnosis of COPD. Logistic regression analysis showed an improved use of spirometry when inhaled corticosteroids were prescribed for asthma (OR = 5.2; CI 2.9-9.2) or COPD (OR = 4.7; CI 2.0-10.6). Spirometry was also used more often when sympathomimetics were prescribed (asthma: OR = 2.3; CI 1.2-4.2; COPD: OR = 4.1; CI 1.8-9.4). CONCLUSIONS: This study revealed that spirometry was used more often when corticosteroids or sympathomimetics were prescribed. The findings suggest that treatment was based on diagnostic test results rather than on recorded diagnoses. The documented ICD-10 codes may not always reflect the real status of the patients. Thus medical care for asthma and COPD in general practice may be better than initially found on the basis of recorded diagnoses, although further improvement of practice patterns in asthma and COPD is still necessary.

Anxiety and depression in patients with pulmonary hypertension.

OBJECTIVE: This is the first study that investigates the prevalence and actual treatment of anxiety, depression, and other mental disorders in patients with pulmonary hypertension (PH). The prevalence of mental disorders in patients with PH was compared with parallel groups of primary care patients and patients with inflammatory rheumatic diseases, and the relationship between functional status and prevalence of mental disorders was determined. METHODS: The patient group with PH (70.1% female; mean age, 47.8 +/- 12.7 years) and the two comparison groups, which were matched by age and sex, consisted of 164 patients each. Patients completed self-administered instruments, including the Patient Health Questionnaire for the diagnosis of mental disorders. New York Heart Association (NYHA) functional class was assessed in all patients with PH. RESULTS: Thirty-five percent of the patients with PH suffered from mental disorders, with the most common being major depressive disorder (15.9%) and panic disorder (10.4%). Both panic disorder and panic attacks were significantly more prevalent in patients with PH than in either patients with inflammatory rheumatic diseases or primary care patients. The prevalence of mental disorders in patients with PH increased significantly with functional impairment, from 17.7% (NYHA class I) to 61.9% (NYHA class IV). Only 24.1% of the patients with PH with mental disorders were receiving psychopharmacological or psychotherapeutic treatment. CONCLUSIONS: Anxiety and depression are frequent in patients with PH and increase as the severity of disease progresses. Given the fact that safe and efficacious treatments of mental disorders are available, greater importance should be attached to the diagnosis and treatment of these conditions in patients with PH.

Regulation of protein kinase C isozymes in volume overload cardiac hypertrophy.

Protein kinase C (PKC) is a family of at least 11 isozymes and known to play a crucial role in myocardial growth. The present study was performed to investigate whether PKC-isozymes are differentially regulated during the development of volume-overload cardiac hypertrophy. After 2, 7 and 30 days of sham or aortocaval shunt operation in male Wistar rats, PKC-activity and the expression of cardiac PKC-isozymes (PKC-alpha, delta and epsilon) were determined at the protein and at the mRNA-level in the left and the right ventricle separately. Myocardial hypertrophy after 2, 7 and 30 days of aortocaval shunt was more pronounced in the right than in the left ventricle. Right ventricular hypertrophy was associated with an increased PKC-enzyme activity, a selectively enhanced protein expression of cytosolic PKC-delta (day 7: +83 +/- 12%, day 30: +94 +/- 14%) and PKC-alpha (day 7: +48 +/- 11%, day 30: +62 +/- 16%) and a transcriptional upregulation of the absolute mRNA-levels of these PKC-isozymes in the aortocaval shunt group as compared to controls. In contrast, the expression of PKC-epsilon was unchanged. A significant upregulation of PKC-delta both on the protein and on the mRNA-level was also noted in volume-overload induced left ventricular hypertrophy, whereas the expression of PKC-alpha and PKC-epsilon were not altered. Furthermore, the expression of calcineurin in both ventricles was not significantly changed in response to volume-overload. This study characterizes in the left and right ventricle a differential regulation of the dominant PKC-isozymes in volume-overload cardiac hypertrophy both at the protein and at the mRNA-level.

Assessment of pulmonary hypertension by CT and MR imaging.

In the recent World Health Organization (WHO) classification the group of pulmonary arterial hypertension (PH) comprises the classic primary pulmonary hypertension and several conditions with definite or very high risk factors to develop pulmonary arterial hypertension. Therapeutic advances drive the need for a comprehensive pre-therapeutic evaluation for optimal treatment. Furthermore, follow-up examinations need to be performed to monitor changes in disease status and response to therapy. Up to now, the diagnostic imaging work-up of PH comprises mainly echocardiography, invasive right heart catheterization and ventilation/perfusion scintigraphy. Due to technical advances helical computed tomography (CT) and magnetic resonance imaging (MRI) became more important in the evaluation and for differential diagnosis of pulmonary arterial hypertension. Both modalities are reviewed and recommendations for clinical use are given.

[Suspected diagnosis of bronchial asthma--development of an algorithm for diagnosis of asthma in general practice]. / Verdacht auf Asthma bronchiale--Entwicklung eines Algorithmus zur Stufendiagnostik in der Hausarztpraxis.

In 2003, the German Ministry of Health will publish a legal document that will allow for the implementation of disease management programmes for asthma and COPD. Examination of German asthma guidelines reveals that they do not include recommendations for a stepwise diagnostic work-up of patients with relevant symptoms in general practice. Therefore an algorithm was developed for the diagnosis of asthma in general practice, based on both national and the most important foreign guidelines providing specific advice on diagnostic procedures.

Right ventricular hypertrophy and apoptosis after pulmonary artery banding: regulation of PKC isozymes.

OBJECTIVE: Pressure overload induced by pulmonary artery banding (PAB) leads to right ventricular (RV) hypertrophy and cardiomyocyte apoptosis. The present study was performed to investigate whether protein kinase C isozymes (PKC-alpha, PKC-betaI, PKC-betaII, PKC-delta and PFC- epsilon ), calcineurin and the renin-angiotensin system (RAS) contribute to PAB-induced cardiac remodeling. METHODS AND RESULTS: PAB in male Wistar rats for 3 weeks results in enhanced PKC activity (as determined by ELISA assay) in the cytosol and membrane fraction of the hypertrophied RV, which was accompanied by increased expression (as determined by Western blot analysis) of cytosolic PKC-delta (+72%), PKC-alpha (+49%), and PKC-betaI (+39%), but not PKC-betaII and PKC- epsilon. This differential regulation of cardiac PKC isozymes was limited to the strained ventricle and was not altered in response to chronic angiotensin-converting enzyme inhibition with ramiprilate. Furthermore, no significant changes in the expression of calcineurin alpha and beta subunits were observed in RV pressure overload compared to controls. PAB-induced cardiac apoptosis was determined using Western blot analysis by a significantly increased expression of Bax protein and caspase-3 in the hypertrophied RV, which was diminished to almost control levels by chronic ramiprilate treatment. The myocardial expression of Bcl-2 was not significantly altered in the experimental groups. CONCLUSION: We have shown for the first time that PAB-induced RV hypertrophy is associated with a differential regulation of cardiac PKC isozymes independent of the RAS and further provide evidence for a pivotal role of the RAS in the development of PAB-induced cardiac apoptosis.