Insight of CO2 and ethanol emission from maize silage: A case study with real-time identification of aerobic and anaerobic microbial respiration using a multi-sensor-fusion method

Silage is produced worldwide for both livestock feeding and biogas production. Sustainable silage production requires characterization and mitigation of potential effects on environmental quality, particularly from greenhouse gas emissions during the production cycle. Ex-situ sampling has demonstrated that major emissions are carbon dioxide (CO2) and ethanol (EtOH). In-situ gas measurements from farm silo and bale silage are rare and may be important to improve our knowledge of the physical and biochemical causes, and constraints on these gas emissions. This study focused on tracking the kinetics of CO2 and EtOH emissions from bale maize silage, with real-time identification, quantification and separation of aerobic and anaerobic respiratory components in the period following opening of the silage. For this, an automatic multi-sensor gas-flux chamber (AMGC) was developed. Three bales (mean weight: 890 kg) of maize silage were tested (n = 3). Oxygen (O2) and temperature (Tsi) sensors were co-located at 10- and 20-cm behind the open face of the bales. Over the two weeks of the experiment we observed: (i) significant initial discharge of CO2 across the open face (1.68-2.55 mol m-2 h-1) and EtOH (0.027-0.034 mol m-2 h-1); (ii) peak CO2 emission occurred when O2 concentration (10 cm depth) was 3∼8% vol., while peak EtOH emission occurred below 2% vol. O2, (iii) dynamic conversion of O2 to CO2 from aerobic respiration; and (iv) the cumulative emission of EtOH during the anaerobic period was 4-6 times greater than that during aerobic plus semi-aerobic periods. These novel measurements provide mechanistic understanding, and may facilitate improved management of silage production to minimize environmental impact and aerobic loss of silage.

Quantification of systolic anterior motion of the mitral valve to predict left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy

Background

In patients with hypertrophic cardiomyopathy (HCM), left ventricular outflow tract obstruction (LVOTO) is associated with an increased risk of heart failure and death (1). It is typically caused by dynamic systolic anterior motion (SAM) of the mitral valve leaflet. SAM can be categorized by echocardiography but diagnostic accuracy is limited by high inter-observer variability.

Purpose

To investigate the accuracy of echocardiographic parameters quantifying systolic motion of the mitral valve leaflets to identify LVOTO in patients with HCM.

Methods

We present a cross-sectional analysis of the HyperCard Registry, a prospective single-center cohort study enrolling consecutive patients with suspected or confirmed HCM. For the present analysis, patients with confirmed HCM and a valid standardized transthoracic echocardiographic were included. LVOT gradients were measured at rest and during Valsalva maneuver using continuous wave Doppler. In patients with clinical suspicion of dynamic LVOTO, further provocation maneuvers were conducted. LVOTO was defined as a maximal peak LVOT gradient ≥30 mmHg. Parameters quantifying systolic motion of the mitral valve were measured in parasternal and apical views, both at early and late systole, by an investigator blinded to individual patient characteristics. SAM was visually assessed and categorized into grade 0 (no SAM), I (leaflet motion towards LVOT), II (late systolic septal contact), and III (early systolic septal contact).

Results

We analyzed 142 patients (59±13 years, 42% women). LVOTO was present in 68 (48%) patients of whom 30 (21% of all) exhibited LVOTO at rest, and 38 (27% of all) had LVOTO only during provocation maneuvers (ie. dynamic LVOTO). SAM was present in 86 patients (60%) and had a sensivitiy, specificity and PPV of LVOTO of 91%, 69% and 73%, respectively (table). The late-systolic distance between mitral leaflet tip and anterior septum (TISls) measured in apical 3-chamber view was best associated with the degree of SAM (F=123, P<0.001), and with peak LVOT gradient (at rest: Pearson r=−0.817; during Valsalva maneuver: r=−0.816, both P<0.001). In ROC analyses (figure), the AUC of TISls for identification of LVOTO and dynamic LVOTO were 0.914 (95% CI 0.868–0.959) and 0.857 (0.786–0.927), respectively. TISls ≤14 mm had a 97% sensitivity for LVOTO and of 94% for dynamic LVOTO. TISls ≤9 mm showed specificity and PPV of 95% and 92% for LVOTO, and 94% and 83% for dynamic LVOTO, respectively.

Conclusions

Quantification of SAM by TISls showed high diagnostic accuracy in identifying HCM patients with LVOTO. Prospective studies are needed to assess the incremental benefit of this novel parameter in the diagnostic work-up of HCM patients.

Funding Acknowledgement

Type of funding sources: None.

P148 CANCER INCIDENCE AND MORTALITY ACCORDING TO PRE–EXISTING HEART FAILURE IN A COMMUNITY–BASED COHORT

Background

Studies assessing whether heart failure (HF) is associated with an excess risk of cancer and cancer–related mortality yielded conflicting results. Here, we assessed the incidence and mortality of cancer according to the presence of HF in a community–based cohort.

Methods

By reviewing the health care records of the Puglia region in Italy, we first selected the individuals ≥50–year–old, with no history of cancer within 3 years before the baseline evaluation and ≥5 years of follow–up, during the period from January 1st, 2005 to December 31st, 2013. Next, we matched 1:1 104,020 subjects with HF at baseline and 104,020 controls based on age, sex, Drug–Derived Complexity Index, and follow–up duration. Cancer incidence and mortality were analyzed by Kaplan–Meier method and Cox regression models. Fine and Grey’s regression model was also used to compare cancer–specific mortality while taking into account the competing risk of non–cancer death.

Results

Overall, the mean age of the study population was 76±10 years and the mean follow–up was 5.7 years. The incidence rate of cancer in HF patients and controls was 21.36 (95%CI, 20.98–21.74) and 12.42 (95%CI, 12.14–12.72) per 1000 person/years, respectively, corresponding to a 76% higher risk of incident cancer in HF patients (HR, 1.76; 95%CI, 1.71–1.81). HF patients also died from cancer more frequently than controls (HR 4.11; 95%CI, 3.86–4.38; Figure 1). This excess mortality was highest when age was <70 years (HR 7.54, 95%CI 6.33–8.98), and declined in subjects aged 70–79 years (HR 3.80, 95%CI 3.44–4.19) and ≥80 years (HR 3.10, 95%CI 2.81–3.43). The association of HF with cancer mortality was confirmed in the competing risk analysis (subdistribution HR 3.48, 95%CI 3.27–3.72), as well as the interaction with age: <70 years of age: SHR 6.65, 95%CI 5.60–7.94; 70–80 years: SHR 3.14, 95%CI 2.84–3.48; and ≥80 years: SHR 2.81, 95%CI 2.55–3.10. The HF–related risk applied to the majority of cancer types. Interestingly, among HF patients a high consumption of loop diuretic (≥80 mg/d of furosemide equivalents for ≥30 days in the year before the index date) was associated with a higher mortality for cancer (HR 1.35, 95%CI 1.19–1.53 vs. ≤37.5 mg/d).

Conclusions

The analysis of this large community–based sample suggests that HF does portend an increased risk of cancer and cancer–related mortality, which is blunted, yet remains substantial, with increasing age and competing risk of dying from other causes.

Myocardial work in hypertrophic cardiomyopathy - a new non-invasive parameter for segmental myocardial function?

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): DFG

Introduction

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiac disease. Alcohol septal ablation (PTSMA) is an established treatment option for patients with intracavitary obstruction. In non-obstructive patients, measurement of myocardial work (MW) using pressure strain loops was introduced as a new non-invasive tool to estimate myocardial performance.

Purpose

In this preliminary study, we compared global constructive work (GCW) and global wasted work (GWW) as well as the respective values for the septal- and lateral-basal segments in HOCM after successful PTSMA and non-obstructive HCM.

Methods

We included 12 patients (4 women, mean age 59.1 ± 17.6 years) with non-obstructive (maximal left ventricular gradient <30 mmHg; mean 10.6 ± 6.2 mmHg) HCM. 7 (58%) patients (subgroup A) had successful gradient reduction by PTSMA ≥3 months before analysis, whereas 5 patients had non-obstructive HCM (subgroup B). Using echocardiographic measurements of longitudinal strain and non-invasive measurements of peripheral- and calculated (PWA) central blood pressure (BP) as left ventricular systolic pressure (LVSP), we estimated and compared GCW and GWW as well as constructive work (CW) and wasted work (WW) of septal-basal and lateral-basal segments.

Results

In subgroup B, NTproBNP was significant higher than in subgroup A (2050 ± 1957 vs. 552 ± 845 pg/ml; p < 0.05). There were no differences between both subgroups in maximal septal thickness (20.7 ± 2.9 mm (A) vs. 22.2 ± 3.6 mm) and left atrial volume (91.6 ± 33.0 (A) vs. 114.0 ± 49.8 ml (B)). Using the measured peripheral BP as LVSP, GCW (1653 ± 347 (A) mmHg% vs 1641 ± 698mmHg%) and GWW (171 ± 89mmHg% (A) vs. 200 ± 126 mmHg%) showed no differences between both subgroups. Compared to published data of a healthy population, values of GCW were lower and values of GWW higher in HCM. Comparison in segmental analysis in subgroup A showed lower CW in septal-basal than in lateral-basal segments (1032 ± 385mmHg% vs. 1929 ± 699 mmHg%). In the subgroup B the finding was the same pattern (1024 ± 504mmHg% vs. 2301 ± 1069 mmHg%). In contrast, WW showed no difference between basal-septal and lateral-basal segments in both subgroups.

Conclusions

Our preliminary data show decreased GCW and increased GWW in HCM patients without obstruction at rest. As expected, we found lower CW in septal-basal segments than lateral-basal in patients after PTSMA with basal-septal-induced therapeutic infarction. Surprisingly, we found the same pattern in non-obstructive HCM patients. This finding might be one pathophysiological reason for not developing LVOT obstruction, which should be investigated in further detail.

Cancer incidence and mortality according to pre-existing heart failure in a community-based cohort

Background

Studies assessing whether heart failure (HF) is associated with an excess risk of cancer and cancer-related mortality yielded conflicting results. Here, we assessed the incidence and mortality of cancer according to the presence of HF in a community-based cohort.

Methods

By reviewing the health care records of the Puglia region in Italy, we first selected individuals ≥50-year-old, with no history of cancer within 3 years before the baseline evaluation and ≥5 years of follow-up, during the period from January 1st, 2005 to December 31st, 2013. Next, we matched 1:1 104,020 subjects with HF at baseline and 104,020 controls based on age, sex, Charlson Comorbidity Index, Drug-Derived Complexity Index, and follow-up duration. Cancer incidence and mortality were analyzed by Kaplan-Meier method and Cox regression models. Fine and Grey's regression model was also used to compare cancer-specific mortality while taking into account the competing risk of non-cancer death.

Results

Overall, the mean age of the study population was 76±10 years and the mean follow-up was 5.7 years. The incidence rate of cancer in HF patients and controls was 21.36 (95% CI, 20.98–21.74) and 12.42 (95% CI, 12.14–12.72) per 1000 person/years, respectively, corresponding to a 76% higher risk of incident cancer in HF patients (HR, 1.76; 95% CI, 1.71–1.81). HF patients also died from cancer more frequently than controls (HR 4.11; 95% CI, 3.86–4.38; Figure 1). This excess mortality was highest when age was <70 years (HR 7.54, 95% CI 6.33–8.98), and declined in subjects aged 70–79 years (HR 3.80, 95% CI 3.44–4.19) and ≥80 years (HR 3.10, 95% CI 2.81–3.43). The association of HF with cancer mortality was confirmed in the competing risk analysis (HR 3.48, 95% CI 3.27–3.72), as well as the interaction with age: <70 years of age: HR 6.65, 95% CI 5.60–7.94; 70–80 years: HR 3.14, 95% CI 2.84–3.48; and ≥80 years: HR 2.81, 95% CI 2.55–3.10.

The HF-related risk applied to the majority of cancer types, with the exception of neoplasm of the male reproductive system. Interestingly, among HF patients a high consumption of loop diuretic (>37.5 mg/d of furosemide) was associated with a higher mortality for cancer (HR 1.34, 95% CI 1.26–1.42 vs. ≤37.5 mg/d).

Conclusions

The analysis of this large community-based sample suggests that HF does portend an increased risk of cancer and cancer-related mortality, which is blunted, yet remains substantial, with increasing age and competing risk of dying from other causes. The risk of cancer may be heightened when HF is poorly compensated.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Cancer mortality in HF patient

Role of inflammation and comorbidities in the association of heart failure with incident cancer in the HUNT3 cohort

Background

Conflicting data exist regarding the risk of cancer in patients with heart failure (HF). It was first reported that incident cancer is more common among patients with than without HF, whereas more recent studies indicate that this association is primarily driven by comorbidities. HF, cancer, and comorbidities, such as chronic kidney disease (CKD) and chronic obstructive pulmonary disease (COPD), share numerous risk factors, including a state of chronic low-grade inflammation reflected by elevated circulating levels of pro-inflammatory cytokines. The objective of this analysis was to assess whether chronic low-grade inflammation, as measured by levels of high-sensitivity C-reactive protein (hsCRP), and comorbidities mediate the association of HF with incident cancer.

Methods

We used data from the 3rd wave of the Nord-Trøndelag Health Study (HUNT3), a population-based study that enrolled 50,803 individuals ≥18-year-old between October 2006 and June 2008 in the Nord-Trøndelag County (Norway), from the Cancer Registry of Norway and from the administrative health care records of the same region. Associations between baseline characteristics and the development of cancer were assessed using Cox proportional hazards regression models, using time from HUNT3 enrollment as the time scale. Analyses were performed using R statistical software, version 4.0.2.

Results

In HUNT3, hsCRP was measured in 47,571 individuals at the time of enrollment. Of these, we excluded 2,308 patients because of missing information, leaving a cohort of 45,263 subjects. Figure 1 shows the characteristics of the study population at baseline stratified by hsCRP tertiles. The prevalence of cardiovascular disease, comorbidities, and obesity was progressively higher with increasing concentrations of hsCRP.

During a median follow-up of 12 years, there were 66/408 cases of incident cancer in patients with HF at baseline and 5,024/47,163 in subjects without HF, with a more than 2-fold (HR 2.30; 95% CI 1.80–2.93; p<0.001) increase in risk of developing cancer. After adjusting for age and sex, the excess risk decreased to 43% (HR 1.43; 95% CI 1.12–1.82). When including hsCRP in the model, the HF-related risk of cancer was 33% (HR 1.33; CI 1.04–1.70; p=0.022). Furthermore, when body mass index, CKD, COPD, and smoking and drinking habits were included in the model, the risk of cancer in HF patients compared to individuals without HF was no longer significant (HR 1.23; 95% CI 0.94–1.60; p=0.127). Age, male sex, hsCRP, COPD, obesity, and smoking habits were all associated with an increased risk of cancer (Figure 2).

Conclusions

The increased risk of cancer in HF patients compared with the general population is at least in part explained by concomitant inflammation and comorbidities.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

A Multi-Sensor Mini-Bioreactor to Preselect Silage Inoculants by Tracking Metabolic Activity in situ During Fermentation

The microbiome in silage may vary substantially from the onset to the completion of fermentation. Improved additives and inoculants are being developed to accelerate the ensiling process, to enhance fermentation quality, and to delay spoilage during feed-out. However, current methods for preselecting and characterizing these amendments are time-consuming and costly. Here, we have developed a multi-sensor mini-bioreactor (MSMB) to track microbial fermentation in situ and additionally presented a mathematical model for the optimal assessment among candidate inoculants based on the Bolza equation, a fundamental formula in optimal control theory. Three sensors [pH, CO₂, and ethanol (EtOH)] provided data for assessment, with four additional sensors (O₂, gas pressure, temperature, and atmospheric pressure) to monitor/control the fermentation environment. This advanced MSMB is demonstrated with an experimental method for evaluating three typical species of lactic acid bacteria (LAB), Lentilactobacillus buchneri (LB) alone, and LB mixed with Lactiplantibacillus plantarum (LBLP) or with Enterococcus faecium (LBEF), all cultured in De Man, Rogosa, and Sharpe (MRS) broth. The fermentation process was monitored in situ over 48 h with these candidate microbial strains using the MSMB. The experimental results combine acidification characteristics with production of CO₂ and EtOH, optimal assessment of the microbes, analysis of the metabolic sensitivity to pH, and partitioning of the contribution of each species to fermentation. These new data demonstrate that the MSMB associated with the novel rapid data-processing method may expedite development of microbial amendments for silage additives.

Optimisation of dry matter and nutrients in feed rations through use of a near-infrared spectroscopy system mounted on a self-propelled feed mixer

Context Knowledge of the nutrient requirements of dairy cows, and the nutritional composition and physical form of the feed resources used to prepare the total mixed ration (TMR) of basic and concentrated feeds, is essential to achieving high milk yields, health and welfare in modern commercial herds. Grass and maize silage components can vary widely in composition depending on harvesting intervals and weather; thus, the distribution of dry matter (DM) and nutrients in silos may vary greatly, resulting in serious errors during sampling and analysis. In addition, the flow of information from the stored silage stops once the forages are stored in the silo. Aims The objective of this study was to develop a practical approach for measuring variations in DM and silage quality parameters (crude protein, fibre, ash and fat) during the feed-extraction process from a bunker silo by a self-propelled feed mixer, which would ultimately help farmers to optimise the TMR. Methods . Near-infrared spectroscopy (NIRS) technology was used to estimate fodder DM and nutrient contents in the material flow. Wet chemical analyses were used for preliminary evaluation of grass and maize silage samples. A portable NIRS was developed to record the spectra of various silage samples. Key results The spans of calibration of sample DM content were 21.3–59.2% for grass and 26–46.7% for maize. Crude protein content had span values of 11.4–18.3% for the grass silage and 5.4–10.8% for the maize silage models. Conclusions NIRS technology was used successfully to estimate the DM and nutrient contents of the fodder. The location for the functional unit on the self-propelled feed mixer may need to be modified for series production because it is not fully accessible. Implications NIRS is a suitable method for measuring DM and nutrient contents continuously during feed extraction from the bunker silo and can be used to help farmers to optimise the TMR.

Corrigendum to: Optimisation of dry matter and nutrients in feed rations through use of a near-infrared spectroscopy system mounted on a self-propelled feed mixer

Context Knowledge of the nutrient requirements of dairy cows, and the nutritional composition and physical form of the feed resources used to prepare the total mixed ration (TMR) of basic and concentrated feeds, is essential to achieving high milk yields, health and welfare in modern commercial herds. Grass and maize silage components can vary widely in composition depending on harvesting intervals and weather; thus, the distribution of dry matter (DM) and nutrients in silos may vary greatly, resulting in serious errors during sampling and analysis. In addition, the flow of information from the stored silage stops once the forages are stored in the silo. Aims The objective of this study was to develop a practical approach for measuring variations in DM and silage quality parameters (crude protein, fibre, ash and fat) during the feed-extraction process from a bunker silo by a self-propelled feed mixer, which would ultimately help farmers to optimise the TMR. Methods Near-infrared spectroscopy (NIRS) technology was used to estimate fodder DM and nutrient contents in the material flow. Wet chemical analyses were used for preliminary evaluation of grass and maize silage samples. A portable NIRS was developed to record the spectra of various silage samples. Key results The spans of calibration of sample DM content were 21.3–59.2% for grass and 26–46.7% for maize. Crude protein content had span values of 11.4–18.3% for the grass silage and 5.4–10.8% for the maize silage models. Conclusions NIRS technology was used successfully to estimate the DM and nutrient contents of the fodder. The location for the functional unit on the self-propelled feed mixer may need to be modified for series production because it is not fully accessible. Implications NIRS is a suitable method for measuring DM and nutrient contents continuously during feed extraction from the bunker silo and can be used to help farmers to optimise the TMR.

Fibrotic remodeling of left ventricle in the murine remnant kidney model of chronic kidney disease is independent of arterial hypertension

Background

Cardiac fibrosis and arterial hypertension are common in patients with chronic kidney disease (CKD). We studied the mechanisms of cardiac fibrogenesis and the role of blood pressure in mice with CKD.

Methods and results

10-week-old male C57/BL6N (BL6) and SV129 wildtype (WT) mice were underwent 5/6 nephrectomy (remnant kidney model, RKM) or sham operation for 10 weeks. RKM significantly elevated plasma creatinine and urea. RKM elicited both interstitial and replacement renal and left ventricular (LV) (BL6: SHAM 5.6±0.4%, RKM 7.3±0.7%, p=0.04; SV129: SHAM 6.0±0.5%, RKM 14±2%, p=0.001) fibrosis as assessed by picrosirius red staining. In parallel, the number of cardiac fibroblasts per mm2 (BL6: SHAM 36±4, RKM 85±13, p=0.001; SV129: SHAM 82±11, RKM 200±34, p=0.006) was increased in RKM mice. With regard to possible mechanisms, cardiac oxidative stress as shown by co-immunostaining for intracellular fibronectin and 8-hydroxyguanosine (BL6: SHAM 44±14%, RKM 60±24%, p=0.03; SV129: SHAM 51±6%, RKM 70±7%, p=0.04) and the percentage of CXCR4+ fibroblasts in the myocardium (BL6: SHAM 47±5%, RKM 62±4%, p=0.04; SV129: SHAM 63±5%, RKM 81±3%, p=0.005) were increased. Furthermore, the number of circulating CD45+ / collagen I+ fibrocytes (FACS) in the peripheral blood was increased by RKM in BL6 (SHAM 100±23%, RKM 443±252%, p=0.04) and diminished in SV129 (SHAM 100±19%, RKM 43±11%, p=0.01), while an opposite regulation was seen in the bone marrow. To further confirm the role of bone-marrow derived fibroblasts in renal and cardiac remodeling 10-week-old WT BL6 mice were subjected to transplantation of bone marrow from 10-week-old WT BL6 mice expressing green fluorescent protein (GFP)+ ubiquitously. 28 days later, RKM or SHAM-operation was performed. RKM significantly increased the number of GFP+ fibroblasts in kidney and LV-myocardium. CKD significantly decreased myocardial capillarization assessed by immunostaining for podocalyxin in both mouse lines. In parallel, myocardial protein expression of fibrosis regulators fibronectin, collagen I, CTGF and Hif1a were up-regulated and expression of the active form of eNOS (phospho-S1177) was reduced.

As a possible confounder, tail-cuff blood pressure was moderately enhanced (Ø 30mmHg) 9 weeks after nephrectomy. In a control experiment using the vasodilator hydralazine (250 mg/L/day), peripheral blood pressure was equalized in all 4 experimental groups, but the extent of LV fibrosis and expression of the above-mentioned fibrosis markers remained unchanged.

Conclusions

Chronic kidney disease in the RKM model elicits left ventricle fibrosis by increasing myocardial protein expression of fibrosis regulators, reduction of myocardial capillarization and mobilization / recruitment of circulating fibroblasts, independently of blood pressure.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Deutsche Forschungsgemeinschaft

Prevalence and determinants of the precursor stages of heart failure: results from the population-based STAAB cohort study

Aims

Prevention of heart failure relies on the early identification and control of risk factors. We aimed to identify the frequency and characteristics of individuals at risk of heart failure in the general population.

Methods and Results

We report cross-sectional data from the prospective Characteristics and Course of Heart Failure Stages A–B and Determinants of Progression (STAAB) cohort study investigating a representative sample of residents of Würzburg, Germany. Sampling was stratified 1:1 for sex and 10:27:27:27:10 for age groups of 30–39/40–49/50–59/60–69/70–79 years. Heart failure precursor stages were defined according to American College of Cardiology/American Heart Association: stage A (risk factors for heart failure), stage B (asymptomatic cardiac dysfunction). The main results were internally validated in the second half of the participants. The derivation sample comprised 2473 participants (51% women) with a distribution of 10%/28%/25%/27%/10% in respective age groups. Stages A and B were prevalent in 42% and 17% of subjects, respectively. Of stage B subjects, 31% had no risk factor qualifying for stage A (group ‘B-not-A’). Compared to individuals in stage B with A criteria, B-not-A were younger, more often women, and had left ventricular dilation as the predominant B qualifying criterion (all P < 0.001). These results were confirmed in the validation sample (n = 2492).

Conclusion

We identified a hitherto undescribed group of asymptomatic individuals with cardiac dysfunction predisposing to heart failure, who lacked established heart failure risk factors and therefore would have been missed by conventional primary prevention. Further studies need to replicate this finding in independent cohorts and characterise their genetic and -omic profile and the inception of clinically overt heart failure in subjects of group B-not-A.

P4997Raf kinase inhibitor protein of the bone marrow contributes to cardiac fibrogenesis in pressure-overloaded myocardium

Background

Raf Kinase Inhibitor Protein (RKIP) regulates myocardial remodeling under conditions of enhanced myocardial oxidative stress in pressure-overloaded left ventricle (LV) modulating myocardial production of reactive oxygen species (ROS). A second mode of action may be the mobilization of circulating fibroblasts (fibrocytes) from the bone-marrow (BM). However the underlying mechanisms are incompletely understood.

Methods and results

To further characterize the role of RKIP in BM cells for myocardial remodeling 10-week-old wild-type (WT) C57BL/6N mice were subjected to transplantation of bone marrow (BMT) from 10-week-old C57BL/6-RKIP-deficient (RKIP−/−) N or WT C57BL/6N mice expressing green fluorescent protein (GFP)+ ubiquitously. 28 days later, transverse aortic constriction (TAC, 360 μm) or SHAM-operation was performed. 5 weeks post TAC, LV systolic pressure (LVSP) and heart weight to tibia length ratio were significantly increased in both types of BMT, compared with corresponding SHAM. Increased afterload elicited myocardial fibrosis as assessed by picrosirius red staining (WT/WT SHAM 15±2.5%, WT/WT TAC 21.3±1.4%, p<0.05; RKIP−/−/WT SHAM 17±2%, RKIP−/−/WT TAC 18±3%, p=ns) and significantly increased the number of LV fibroblasts per mm2 estimated by immunostaining for intracellular fibronectin, which were further reduced by transplantation of RKIP−/−N BM (WT/WT SHAM 5499±313, WT/WT TAC 7493±741 per mm2, p<0.05; RKIP−/−/WT SHAM 5737±259, RKIP−/−/WT TAC 5282±551, per mm2, p=ns). Moreover, transplantation of RKIP−/−N BM significantly diminished the number of circulating BM-derived GFP+ fibroblasts in the peripheral blood and LV myocardium during pressure overload (WT/WT SHAM 961±129, WT/WT TAC 2326±273 per mm2, p<0.05; RKIP−/−/WT SHAM 1041±209, RKIP−/−/WT TAC 1518±107, per mm2, p=ns). The myocardial redox status was assessed by the co-immunostaining for ROS production marker 8-hydroxyguanosin (8-dOHG), cardiomyocyte marker α-sarcomeric actin and fibroblast marker intracellular fibronectin. Pressure overload during 5 weeks significantly increased the percentages of 8-dOHG+cardiomyocytes (WT/WT SHAM 34±9%, WT/WT TAC 63±6%, p<0.05; RKIP−/−/WT SHAM 29±6%, RKIP−/−/WT TAC 31±8%, p=ns) and 8-dOHG+fibroblasts (WT/WT SHAM 57±6%, WT/WT TAC 73±4%, p<0.05; RKIP−/−/WT SHAM 58±2%, RKIP−/−/WT TAC 58±7%, p=ns) in mice transplanted with WT BM but not with RKIP−/−N BM.

Conclusions

In pressure-overload induced enhanced myocardial ROS production, deficiency of RKIP-expression in the bone marrow abrogates left ventricular fibrosis by reduction of myocardial ROS production and mobilization of BM-derived fibroblasts. These findings suggest that the function of RKIP in the bone marrow may be important for maladaptive myocardial remodelling.

Acknowledgement/Funding

Deutsche Forschungsgemeinschaft: KA4024/3-1, SFB TRR219; Saarland University HOMFOR, Dr. Marija Orlovich foundation, Corona foundation s199/10060/2014

Variations in cardiovascular risk factors in people with and without migration background in Germany - Results from the STAAB cohort study

BACKGROUND

About 20% of the German population have a migration background which might influence prevalence of preventable cardiovascular risk factors (CVRF).

METHODS

We report data of the prospective Characteristics and Course of Heart Failure Stages A-B and Determinants of Progression (STAAB) cohort study investigating a representative sample of inhabitants of the City of Würzburg, Germany, aged 30 to 79 years. Individuals without migration background were defined as follows: German as native language, no other native language, and/or born in Germany. All other participants were defined as individuals with migration background.

RESULTS

Of 2473 subjects (51% female, mean age 54 ± 12 years), 291 (12%) reported a migration background: n = 107 (37%) from a country within the EU, n = 117 (40%) from Russia, and n = 67 (23%) from other countries. Prevalence of hypertension, atherosclerotic disease, and diabetes mellitus was similar in individuals with and without migration background. By contrast, prevalence of obesity and metabolic syndrome was significantly higher in individuals with migration background, with the least favourable profile apparent in individuals from Russia (individuals without vs. with migration background: obesity 19 vs. 24%, p < 0.05; odds ratio: EU: 1.6, Russia: 2.2*, other countries: 0.6; metabolic syndrome 18 vs. 21%, p < 0.05; odds ratio: EU: 1.2, Russia: 1.7*, other countries: 1.5; *p < 0.05).

CONCLUSION

Individuals with migration background in Germany might exhibit a higher CVRF burden due to a higher prevalence of obesity and metabolic syndrome. Strategies for primary prevention of heart failure may benefit from deliberately considering the migration background.

[Diagnosis and management of acute pulmonary embolism. ESC guidelines 2014]

Acute pulmonary embolism (PE) still represents a challenge regarding a rapid diagnosis and a risk-adapted therapy. In the 2014 guidelines of the European Society of Cardiology (ESC) on the diagnosis and management of acute PE, several new recommendations have been issued based on new study data. Some established scores for risk stratification were developed further and there is now good evidence for the use of age-adjusted D-dimer cut-off levels. For the risk stratification in patients without clinical features of shock, the utilization of the pulmonary embolism severity index (PESI) and simplified PESI (sPESI) scores is recommended. In patients with intermediate risk, right ventricular morphology and function can be evaluated by computer tomography or echocardiography and biomarkers facilitate further risk stratification. For the treatment of patients with venous thromboembolism with or without PE, the non-vitamin K-dependent oral anticoagulants (NOACs) are a safe alternative to the standard anticoagulation regimen with heparin and vitamin K antagonists. Systemic thrombolytic therapy should be restricted to patients with high risk or intermediate high risk with hemodynamic instability. Finally, new recommendations for the diagnosis and therapy of patients with chronic thromboembolic pulmonary hypertension (CTEPH), with cancer or during pregnancy are given.

Developing a Penetrometer-Based Mapping System for Visualizing Silage Bulk Density from the Bunker Silo Face

For silage production, high bulk density (BD) is critical to minimize aerobic deterioration facilitated by oxygen intrusion. To precisely assess packing quality for bunker silos, there is a desire to visualize the BD distribution within the silage. In this study, a penetrometer-based mapping system was developed. The data processing included filtering of the penetration friction component (PFC) out of the penetration resistance (PR), transfer of the corrected penetration resistance (PR_c) to BD, incorporation of Kriged interpolation for data expansion and map generation. The experiment was conducted in a maize bunker silo (width: 8 m, middle height: 3 m). The BD distributions near the bunker silo face were represented using two map groups, one related to horizontal- and the other to vertical-density distribution patterns. We also presented a comparison between the map-based BD results and core sampling data. Agreement between the two measurement approaches (RMSE = 19.175 kg·m⁻³) demonstrates that the developed penetrometer mapping system may be beneficial for rapid assessment of aerobic deterioration potential in bunker silos.

Adenosine A1 receptor activation attenuates cardiac hypertrophy and fibrosis in response to α1 -adrenoceptor stimulation in vivo

BACKGROUND AND PURPOSE

Adenosine has been proposed to exert anti-hypertrophic effects. However, the precise regulation and the role of the different adenosine receptor subtypes in the heart and their effects on hypertrophic signalling are largely unknown. We aimed to characterize expression and function of adenosine A1 receptors following hypertrophic stimulation in vitro and in vivo.

EXPERIMENTAL APPROACH

Pro-hypertrophic stimuli and adenosine A1 receptor stimulation of neonatal rat cardiomyocytes and male C57/Bl6 mice, sc. drug administration, real-time PCR, (3) [H]-leucine-incorporation assay, immunostaining, tissue staining, Western blots, gravimetric analyses and echocardiography were applied in this study.

KEY RESULTS

In neonatal rat cardiomyocyte cultures, phenylephrine, but not angiotensin II or insulin-like growth factor 1 (IGF1), up-regulated adenosine A1 receptors concentration-dependently. The hypertrophic phenotype (cardiomyocyte size, sarcomeric organization, total protein synthesis, c-fos expression) mediated by phenylephrine (10 μM), but not that by angiotensinII (1 μM) or IGF1 (20 ng·mL(-1) ), was counteracted by the selective A1 receptor agonist, N6-cyclopentyladenosine. In C57/BL6 mice, continuous N6-cyclopentyladenosine infusion (2 mg·kg(-1) ·day(-1) ; 21 days) blunted phenylephrine (120 mg·kg(-1) ·day(-1) ; 21 days) induced hypertrophy (heart weight, cardiomyocyte size and fetal genes), fibrosis, MMP 2 up-regulation and generation of oxidative stress - all hallmarks of maladaptive remodelling. Concurrently, phenylephrine administration increased expression of adenosine A1 receptors.

CONCLUSIONS AND IMPLICATIONS

We have presented evidence for a negative feedback mechanism attenuating pathological myocardial hypertrophy following α1 -adrenoceptor stimulation. Our results suggest adenosine A1 receptors as potential targets for therapeutic strategies to prevent transition from compensated myocardial hypertrophy to decompensated heart failure due to chronic cardiac pressure overload.

[Preoperative risk evaluation in heart failure]

The primary target in preoperative risk evaluation is not to classify patients as operable or inoperable but rather to reduce perioperative morbidity and mortality. Indications for perioperative diagnostic and therapeutic procedures are mostly the same as for patients without subsequent non-cardiac surgery. However, the time schedule often depends on cofactors such as urgency and severity of surgical interventions. Perioperative risk management requires exceedingly good communication and collaboration between surgeons, anesthesiologists and internists and offers the chance to diagnose and treat perioperative risk factors in a justifiable time and cost context.

Effect of bisoprolol on perioperative complications in chronic heart failure after surgery (Cardiac Insufficiency Bisoprolol Study II (CIBIS II))

In patients with coronary artery disease undergoing noncardiac surgery, beta-blockers decrease perioperative mortality and nonfatal myocardial infarction. It is presently unknown whether beta-blockers reduce perioperative risk in patients with chronic heart failure. Thus, data of the CIBIS II study were analyzed regarding the effect of bisoprolol on perioperative outcome in patients with moderate to severe heart failure. A total of 2647 patients with heart failure in New York Heart Association (NYHA) class III-IV and left ventricular ejection fraction < or =35% were randomized to bisoprolol or placebo in a double-blind randomized study. Of these patients, 165 underwent surgery (bisoprolol, n = 87; placebo, n = 78). In patients undergoing surgery, mortality was not different between the placebo- and bisoprolol-treated group (7.7% vs 5.8%, p = 0.76). Neither postoperative hospital admission (placebo, 24.4%; bisoprolol, 34.5%, p = 0.17) nor time to postoperative hospital admission (placebo, < or =30 days, n = 2; 31-180 days, n=11; >180 days, n = 6; bisoprolol, n = 9/ 10/11; p = 0.14) were reduced by bisoprolol. Compared to coronary artery disease, perioperative beta-blockade has little effect in patients with chronic heart failure. Therefore, a controlled randomized trial with perioperative beta-blocker treatment in heart failure patients is warranted to further test this hypothesis.

Prospective crossover comparison of carvedilol and metoprolol in patients with chronic heart failure

OBJECTIVES

This study investigates the effects of a change of beta-adrenergic blocking agent treatment from metoprolol to carvedilol and vice versa in patients with heart failure (HF).

BACKGROUND

Beta-blockers improve ventricular function and prolong survival in patients with HF. It has recently been suggested that carvedilol has more pronounced effects on left ventricular ejection fraction (LVEF) compared with metoprolol. It is uncertain whether a change from one beta-blocker to the other is safe and leads to any change of left ventricular function.

METHODS

Forty-four patients with HF due to ischemic (n = 17) or idiopathic cardiomyopathy (n = 27) that had responded well to long-term treatment with either metoprolol (n = 20) or carvedilol (n = 24) were switched to an equivalent dose of the respective other beta-blocker. Before and six months after crossover of treatment, echocardiography, radionuclide ventriculography and dobutamine stress echocardiography were performed.

RESULTS

Six months after crossover of beta-blocker treatment, LVEF had further improved with both carvedilol and metoprolol (carvedilol: 32 +/- 3% to 36 +/- 4%; metoprolol: 27 +/- 4% to 30 +/- 5%; both p < 0.05 vs. baseline), without interindividual differences. There were no changes in either New York Heart Association functional class or any other hemodynamic parameters at rest. Dobutamine stress echocardiography revealed a more pronounced increase of heart rate after dobutamine infusion in metoprolol- compared with carvedilol-treated patients. After dobutamine infusion, LVEF increased in the carvedilol- but not in the metoprolol-treated group.

CONCLUSIONS

When switching treatment from one beta-blocker to the other, improvement of LVEF in patients with HF is maintained. Despite similar long-term effects on hemodynamics at rest, beta-adrenergic responsiveness is different in both treatments.

Treatment of heart failure with beta-blockers. Mechanisms and results

Sympathetic activation is a significant predictor of a poor prognosis in heart failure. Excessive stimulation with norepinephrine produces apoptosis, tachycardia and arrhythmias thereby leading to progression of left ventricular dysfunction and worsening of outcome. Beta-blockers reduce morbidity and improve cardiac function. They have been shown to improve survival (MERIT-HF, CIBIS II and US-Carvedilol Trials). A careful uptitration of dosages is achievable with a low rate of side effects. The mechanism of beta-blocker effects in heart failure are cardiac protection from beta1-adrenoceptor overstimulation, antiarrhythmic effects, reduction in heart rate and positive energetic effects or a combination thereof.

Characterization of beta(1)-selectivity, adrenoceptor-G(s)-protein interaction and inverse agonism of nebivolol in human myocardium

Intrinsic activity and beta(1)-selectivity are important features of beta-blockers in the treatment of patients with coronary syndromes and heart failure. In human myocardium, intrinsic activity and beta(1)-selectivity of the novel beta-adrenoceptor antagonist nebivolol have not yet been determined. The study examines intrinsic activity, beta-adrenoceptor-G-protein coupling and beta(1)-selectivity of nebivolol and bisoprolol in human ventricular myocardium. Furthermore, intrinsic activity of both compounds is compared to the one of bucindolol, carvedilol and metoprolol in human atrial myocardium. Radioligand binding studies ([(125)I]-lodocyanopindolol) were performed on membrane preparations of human failing and nonfailing myocardium and on COS-7 cells transfected with human beta(1)- and beta(2)-adrenoceptors, respectively. Functional experiments were carried out on isolated muscle preparations of human left ventricular and right atrial myocardium from failing and nonfailing hearts. Radioligand binding studies reveal 3 - 4 fold beta(1)-selectivity for nebivolol and 16 - 20 fold beta(1)-selectivity for bisoprolol in human myocardium. In COS-7-cells, beta(1)-selectivity is 3 fold for nebivolol and 15 fold for bisoprolol. Neither the binding of nebivolol nor of bisoprolol is affected by the presence of guanylylimidodiphosphate (Gpp(NH)p). Nebivolol and bisoprolol exert similar inverse agonist activity in human ventricular as well as atrial myocardium. In atrial myocardium, inverse agonism of both compounds is higher compared to bucindolol, equal to carvedilol and lower compared to metoprolol. Favourable haemodynamic effects of nebivolol in humans are not due to beta(1)-selectivity or partial agonist activity of this agent. Other mechanisms, i.e. the production of nitric oxide, may thus be responsible for its unique haemodynamic profile.

Differential effects of carvedilol and metoprolol on isoprenaline-induced changes in beta-adrenoceptor density and systolic function in rat cardiac myocytes

OBJECTIVE

beta-Blockers improve cardiac function and survival in heart failure patients. The underlying mechanisms are not completely elucidated. Differences between agents might be important for the development of more specific therapeutical approaches. This study investigated whether metoprolol or carvedilol alter beta-adrenergic signaling differently.

METHODS

beta-Adrenoceptor density and systolic function were determined in rat adult ventricular cardiac myocytes.

RESULTS

12 h isoprenaline-treatment (Iso, 1 micromol/l) reduced beta-adrenoceptor density by 33% (P<0.01). The effect was abolished by incubation with isoprenaline plus metoprolol (3 micromol/l), but was more pronounced after coincubation with carvedilol (0.003 micromol/l, P<0.05 Carv vs. Iso). Metoprolol alone had no effect on beta-adrenoceptor density, but carvedilol induced a decrease in receptor density even in absence of isoprenaline (P<0.05 Carv vs. ctr.). The isoprenaline (0.0003-10 micromol/l) induced concentration-dependent increase in myocyte shortening was blunted after 12 h preincubation with Iso (1 micromol/l, P<0.001). This reduction was abolished or partly prevented by coincubation with metoprolol or carvedilol, respectively. Carvedilol decreased the number of receptors which had to be occupied by isoprenaline in order to obtain 50% and 90% increase in myocyte cell shortening. Comparison of guanine nucleotide-dependent binding characteristics of isoprenaline, carvedilol and metoprolol revealed beta-receptor agonist like binding characteristics for carvedilol, but antagonist like binding characteristics for metoprolol.

CONCLUSION

Metoprolol but not carvedilol prevents isoprenaline-induced downregulation of myocyte beta-adrenoceptors. The difference might be due to specific binding properties of the beta-blockers. Restoration of isoprenaline responsiveness by carvedilol might be due to improved coupling of beta-receptors to postreceptor effects.

Binding properties of beta-blockers at recombinant beta1-, beta2-, and beta3-adrenoceptors

The human heart contains at least four distinct beta-adrenoceptor subtypes, three of which have been cloned. However, the binding properties of beta-blockers to the different beta-adrenoceptor subpopulations are not yet thoroughly characterized. Human beta1-, beta2- and beta3-adrenoceptors were expressed in COS-7 cells and [125I]iodocyanopindolol saturation binding, and competition experiments with commonly used beta-blockers were performed in the respective membrane preparations. Atenolol and metoprolol were about fivefold selective for beta1- versus beta2- and beta3-adrenoceptors. Bisoprolol was approximately 15-fold selective for beta1- versus beta2- and approximately 31-fold selective for beta1- versus beta3-adrenoceptors. Carvedilol was nonselective for any beta-adrenoceptor subtype. We conclude that the beta1-selectivities of atenolol, metoprolol, and bisoprolol are lower in COS cell membranes compared with previous investigations performed in native membranes. All beta-blockers investigated bind to beta3-adrenoceptors. Differential binding properties to beta3-adrenoceptors might imply different responses as to body weight, cardiac contractility, heart rate, and growth regulation. This might imply differential indications for the drugs investigated.

Different intrinsic activities of bucindolol, carvedilol and metoprolol in human failing myocardium

1. Clinical studies have shown different effects of beta-blockers on the beta-adrenergic system, tolerability and outcome in patients with heart failure. 2. The study examines beta-adrenoceptor-G-protein coupling and intrinsic activity of bucindolol, carvedilol and metoprolol in human ventricular myocardium. 3. Radioligand binding studies ([(125)I]-Iodocyanopindolol) were performed in membrane preparations of human failing and nonfailing myocardium. Functional experiments were carried out in isolated muscle preparations of human left ventricular myocardium from failing hearts. 4. Bucindolol and carvedilol bound non-selectively to beta(1)- and beta(2)-adrenoceptors and exerted guanine nucleotide modulatable binding. Metoprolol was 35-fold beta(1)-selective and lacked guanine nucleotide modulatable binding. 5. All beta-blockers antagonized isoprenaline-induced enhancement of contractility. 6. In preparations in which the coupling of the stimulatory G-protein to adenylate cyclase was facilitated by forskolin, bucindolol increased force of contraction in three and decreased it in five experiments. Carvedilol increased force in one and decreased it in six experiments. Metoprolol decreased force in all experiments by 89. 4+/-2.2% (P<0.01 metoprolol vs carvedilol and bucindolol). The negative inotropic effect of metoprolol was antagonized by bucindolol. 7. It is concluded that differences in intrinsic activity can be detected in human myocardium and have an impact on cardiac contractility. In human ventricular myocardium, bucindolol displays substantially higher intrinsic activity than metoprolol and carvedilol. Bucindolol can behave as partial agonist or partial inverse agonist depending on the examined tissue. 8. Differences in intrinsic activity may contribute to differences in beta-adrenoceptor regulation and possibly to differences in tolerability and outcomes of patients with heart failure.

The Effects of Guided Imagery andMusic Therapy on Reported Change in Normal Adults

This study explores the main changes gained from Guided Imagery and Music (GIM) therapy as described by former clients. It also explores whether gains are integrated into the clients' lives and if those changes stabilize over periods of time after finishing GIM therapy. Questionnaires were sent to GIM therapists who forwarded them to former GIM clients. Twenty-five former GIM clients returned questionnaires directly to the researcher. Results show that the main gains reported by former clients of GIM therapy are (a) getting more in touch with one's emotions, (b) gaining insights into some problems, (c) spiritual growth, (d) increased relaxation, and (e) discovering new parts of oneself. Results also show that GIM therapy might be helpful for clients with symptoms of anxiety and/or fear, and for clients who want to increase their self-esteem. Changes gained during GIM therapy appear to stabilize over a period of time after finishing GIM therapy. They improved after termination of therapy, especially in the mental and transpersonal areas.

Effect of beta-blockers on free radical-induced cardiac contractile dysfunction

BACKGROUND

We examined the effects of hydroxyl radicals (OH.) on human myocardial contractility and on sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) activity and the effects of the beta-receptor antagonists metoprolol, carvedilol, and its metabolite BM-910228.

METHODS AND RESULTS

Isometric force of contraction was determined in isolated human myocardium. H(2)O(2) 1 mmol/L and Fe(3+)-nitrilotriacetic acid (Fe(3+)-NTA) 0.1 mmol/L used for generation of OH. induced a decrease in basal force of contraction and an increase in diastolic tension in atrial and left ventricular myocardial preparations. After challenge with OH., the maximum positive inotropic response to Ca(2+) 1.8 to 15 mmol/L was decreased by 60% and by 39%, respectively. The effects of OH. could be blocked by catalase. Carvedilol and its metabolite BM-910228 attenuated the OH.-induced impairment of the inotropic response to Ca(2+) in atrial myocardial preparations. Metoprolol had no significant effect. The stimulation frequency (0.5 to 3.0 Hz)-dependent increase in force of contraction and decrease in diastolic tension were abolished after exposure of atrial trabeculae to OH. In parallel, SERCA activity was decreased by OH. concentration-dependently, as determined in myocardial membrane preparations. BM-910228 partially restored the force-frequency relationship and preserved SERCA activity.

CONCLUSIONS

OH. radicals induce an impairment of contraction and relaxation and an attenuation of the force-frequency relationship in human myocardium accompanied by an inhibition of SERCA. Carvedilol and BM-910228 partly prevented OH.-induced contractile dysfunction. These observations could explain the improvement of ejection fraction in heart failure trials with carvedilol without a restoration of beta-adrenergic receptor density.

Beneficial effects of amiodarone in heart failure: interaction with beta-adrenoceptors rather than G proteins

The effect of the antiarrhythmic drug amiodarone on the human myocardial beta-adrenoceptor-G protein-adenylyl cyclase signalling cascade was investigated. Amiodarone had no effect on myocardial G proteins and maximal adenylyl cyclase activity, but acted as a beta-adrenoceptor antagonist. This mechanism might be at least partially responsible for the beneficial effects of the drug in patients with arrhythmia and heart failure.

Chamber-specific alterations of norepinephrine uptake sites in cardiac hypertrophy

The present study investigated local differences of sympathetic activation and sympathetic neuroeffector defects in nonhypertrophied right and hypertrophied left ventricles in a rat model with renin-induced pressure overload [TG(mREN2)27]. As judged from the depletion of myocardial norepinephrine stores, sympathetic activation was more pronounced in the left than in the right ventricles. In addition, norepinephrine uptake1 carrier sites were reduced in left but unchanged in right ventricles. Gene expression of the carrier was unchanged in stellate ganglia. An increase of Gialpha expression and a heterologous adenylyl cyclase desensitization occurred only in the left but not in the right ventricles, whereas a reduction of beta-adrenergic receptors was observed in both chambers. We concluded that general sympathetic activation can lead to beta-adrenoceptor downregulation but that pressure overload further increases sympathetic activation involving norepinephrine uptake mechanisms in the left ventricles, resulting in heterologous beta-adrenergic desensitization.

Beta-adrenergic signal transduction following carvedilol treatment in hypertensive cardiac hypertrophy

OBJECTIVE

Treatment with the beta-blocker carvedilol leads to an improvement of outcome and ejection fraction in heart failure. These effects occur without affecting the number of beta-adrenergic receptors, as determined in right ventricular biopsies from patients with heart failure. This study was aimed at investigating the effects of carvedilol on beta-adrenergic signal transduction alterations in a model of left ventricular pressure overload, which is characterized by sympathetic activation and a desensitized beta-adrenergic signal transduction.

METHODS

Transgenic rats with overexpression of renin [TG(mREN2)27] were treated with carvedilol (30 micrograms/kg) or held under control conditions and were compared with Sprague-Dawley rats. Myocardial beta-adrenoceptors (125I-labeled iodocyanopindolol binding), Gi alpha (pertussis toxin labeling), Gs alpha-activity (reconstitution into cyc--S49 membranes) and adenylyl cyclase activity were measured. Blood pressure and heart rate, increase in heart rate during sacrifice and pressure rate products were determined.

RESULTS

beta-Adrenoceptors were downregulated and Gi alpha-protein levels were significantly increased, producing a desensitization of basal, isoprenaline- and guanine nucleotide-stimulated adenylyl cyclase activity compared to controls. Carvedilol reduced heart rate, blood pressure and pressure rate product in TG(mREN2)27. Carvedilol did not restore biochemical alterations, but even further reduced beta-adrenoceptor numbers and adenylyl cyclase. It exhibited a two affinity state, guanine nucleotide-sensitive binding to cardiac beta-adrenergic receptors similar to isoprenaline but different from metoprolol.

CONCLUSIONS

Carvedilol did not restore beta-adrenergic signal transduction at concentrations producing antiadrenergic effects in vivo. This effect might be due to an atypical guanine nucleotide-dependent interaction with beta-adrenergic receptors. Thus, ancillary properties could explain the recently reported beneficial effects in patients with heart failure independent from an upregulation of beta-adrenergic receptors.

IGFBP-3 and IGFBP-5 association with endothelial cells: role of C-terminal heparin binding domain

IGFBP-3 and IGFBP-5, but not the other 4 IGF binding proteins, specifically bound to endothelial cell (EC) monolayers. Charged compounds, such as heparin and heparan sulfate, competed for this binding. Of the 6 IGFBPs, IGFBP-3 and IGFBP-5 had the greatest heparin affinity. Peptides of 18 amino acids were synthesized, corresponding to a common basic region of IGFBP-3 (P3), IGFBP-5 and IGFBP-6 (P6) which contained a heparin binding sequence. P3 and P6 inhibited IGFBP-3 and -5 binding to endothelial cell monolayers and the peptides bound directly to EC extracellular matrix. This suggested that the C-terminal basic segment of IGFBP-3/-5 is important for the association of the binding protein with the EC monolayer.