Leucine Supplementation Prevents the Development of Skeletal Muscle Dysfunction in a Rat Model of HFpEF.

Heart failure with preserved ejection fraction (HFpEF) is associated with exercise intolerance due to alterations in the skeletal muscle (SKM). Leucine supplementation is known to alter the anabolic/catabolic balance and to improve mitochondrial function. Thus, we investigated the effect of leucine supplementation in both a primary and a secondary prevention approach on SKM function and factors modulating muscle function in an established HFpEF rat model. Female ZSF1 obese rats were randomized to an untreated, a primary prevention, and a secondary prevention group. For primary prevention, leucine supplementation was started before the onset of HFpEF (8 weeks of age) and for secondary prevention, leucine supplementation was started after the onset of HFpEF (20 weeks of age). SKM function was assessed at an age of 32 weeks, and SKM tissue was collected for the assessment of mitochondrial function and histological and molecular analyses. Leucine supplementation prevented the development of SKM dysfunction whereas it could not reverse it. In the primary prevention group, mitochondrial function improved and higher expressions of mitofilin, Mfn-2, Fis1, and miCK were evident in SKM. The expression of UCP3 was reduced whereas the mitochondrial content and markers for catabolism (MuRF1, MAFBx), muscle cross-sectional area, and SKM mass did not change. Our data show that leucine supplementation prevented the development of skeletal muscle dysfunction in a rat model of HFpEF, which may be mediated by improving mitochondrial function through modulating energy transfer.

Leucine Supplementation Improves Diastolic Function in HFpEF by HDAC4 Inhibition.

Heart failure with preserved ejection fraction (HFpEF) is a complex syndrome associated with a high morbidity and mortality rate. Leucine supplementation has been demonstrated to attenuate cardiac dysfunction in animal models of cachexia and heart failure with reduced ejection fraction (HFrEF). So far, no data exist on leucine supplementation on cardiac function in HFpEF. Thus, the current study aimed to investigate the effect of leucine supplementation on myocardial function and key signaling pathways in an established HFpEF rat model. Female ZSF1 rats were randomized into three groups: Control (untreated lean rats), HFpEF (untreated obese rats), and HFpEF_Leu (obese rats receiving standard chow enriched with 3% leucine). Leucine supplementation started at 20 weeks of age after an established HFpEF was confirmed in obese rats. In all animals, cardiac function was assessed by echocardiography at baseline and throughout the experiment. At the age of 32 weeks, hemodynamics were measured invasively, and myocardial tissue was collected for assessment of mitochondrial function and for histological and molecular analyses. Leucine had already improved diastolic function after 4 weeks of treatment. This was accompanied by improved hemodynamics and reduced stiffness, as well as by reduced left ventricular fibrosis and hypertrophy. Cardiac mitochondrial respiratory function was improved by leucine without alteration of the cardiac mitochondrial content. Lastly, leucine supplementation suppressed the expression and nuclear localization of HDAC4 and was associated with Protein kinase A activation. Our data show that leucine supplementation improves diastolic function and decreases remodeling processes in a rat model of HFpEF. Beneficial effects were associated with HDAC4/TGF-ß1/Collagenase downregulation and indicate a potential use in the treatment of HFpEF.

Effects of homoarginine supplementation on heart and skeletal muscle of rats with heart failure with preserved ejection fraction.

AIM: Heart failure with preserved ejection fraction (HFpEF) is associated with left ventricular stiffness, impaired diastolic relaxation, and severe exercise intolerance. Decreased homoarginine (hArg) levels are an independent predictor of mortality in cardiovascular disease and correlate with impaired exercise performance. We recently reported alterations in arginine, hArg, and related amino acids in obese ZSF1 rats (O-ZSF1), with a HFpEF phenotype. Although low hArg is associated with diastolic dysfunction in humans, potential effects of hArg supplementation were not tested yet. METHODS AND RESULTS: At an age of 6 weeks, 12 O-ZSF1 were randomized into two groups: (1) O-ZSF1 rats supplemented with hArg in their drinking water (sO-ZSF1) or (2) O-ZSF1 rats receiving no hArg supplementation (O-ZSF1). At an age of 32 weeks, effects of primary prevention by hArg supplementation on echocardiographic, histological, and functional parameters of heart and skeletal muscle were determined. Lean ZSF1 rats (L-ZSF1) served as controls. hArg supplementation did not prevent impairment of diastolic relaxation (E/e': O-ZSF1 21 ± 3 vs. sO-ZSF1 22 ± 3, P = 0.954, L-ZSF1 18 ± 5) but resulted in more cardiac fibrosis (histological collagen staining: +57% in sO-ZSF1 vs. O-ZSF1, P = 0.027) and increased collagen gene expression (Col1a1: +48% in sO-ZSF1 vs. O-ZSF1, P = 0.026). In contrary, right ventricular function was preserved by hArg supplementation (TAPSE (mm): O-ZSF1 1.2 ± 0.3 vs. sO-ZSF1 1.7 ± 0.3, P = 0.020, L-ZSF1 1.8 ± 0.4). Musculus soleus maximal specific muscle force (N/cm2 ) in O-ZSF1 (30.4 ± 0.8) and sO-ZSF1 (31.9 ± 0.9) was comparable but significantly reduced compared with L-ZSF1 (36.4 ± 0.7; both P < 0.05). Maximal absolute muscle force (g) (O-ZSF1: 177.6 ± 7.8, sO-ZSF1: 187.8 ± 5.0, L-ZSF1: 181.5 ± 7.9, all P > 0.05) and cross-sectional fibre area (arbitrary units) (O-ZSF1: 1697 ± 57, sO-ZSF1: 1965 ± 121, L-ZSF1: 1691 ± 104, all P > 0.05) were not altered. CONCLUSIONS: Preservation of physiological hArg level in HFpEF may not be suited to prevent alterations in left ventricular and skeletal muscle function and structure. However, hArg supplementation may be beneficial for right ventricular function especially in pulmonary hypertension in HFpEF. We may speculate that clinically observed decreased hArg level are not the cause but the consequence of a yet unrecognized pathomechanism that underpins HFpEF.

Towards a personalised approach in exercise-based cardiovascular rehabilitation: How can translational research help? A 'call to action' from the Section on Secondary Prevention and Cardiac Rehabilitation of the European Association of Preventive Cardiology.

The benefit of regular physical activity and exercise training for the prevention of cardiovascular and metabolic diseases is undisputed. Many molecular mechanisms mediating exercise effects have been deciphered. Personalised exercise prescription can help patients in achieving their individual greatest benefit from an exercise-based cardiovascular rehabilitation programme. Yet, we still struggle to provide truly personalised exercise prescriptions to our patients. In this position paper, we address novel basic and translational research concepts that can help us understand the principles underlying the inter-individual differences in the response to exercise, and identify early on who would most likely benefit from which exercise intervention. This includes hereditary, non-hereditary and sex-specific concepts. Recent insights have helped us to take on a more holistic view, integrating exercise-mediated molecular mechanisms with those influenced by metabolism and immunity. Unfortunately, while the outline is recognisable, many details are still lacking to turn the understanding of a concept into a roadmap ready to be used in clinical routine. This position paper therefore also investigates perspectives on how the advent of 'big data' and the use of animal models could help unravel inter-individual responses to exercise parameters and thus influence hypothesis-building for translational research in exercise-based cardiovascular rehabilitation.

Electromyostimulation to fight atrophy and to build muscle: facts and numbers.

In recent years, electrical myostimulation (EMS) is becoming more and more popular to increase muscle function and muscle weight. Especially it is applied in healthy individual after injury to rebuild muscle mass and in severely atrophic patients who are not able or willing to perform conventional exercise training programs. Studies in experimental models as well as in human subjects confirmed that EMS can increase muscle mass by around 1% and improve muscle function by around 10-15% after 5-6 weeks of treatment. Despite a severe increase in circulating creatine kinase during the first session, EMS can be regarded as a safe therapeutic intervention. At the molecular level, EMS improves the anabolic/catabolic balance and stimulates the regenerative capacity of satellite cells. EMS intensity should be as high as individually tolerated, and a minimum of three sessions per week [large pulses (between 300-450 µs), high frequency (50-100 Hz in young and around 30 Hz in older individuals)] for at least 5-6 weeks should be performed. EMS improved functional performances more effectively than voluntary training and counteracted fast type muscle fibre atrophy, typically associated with sarcopenia. The effect of superimposing EMS on conventional exercise training to achieve more muscle mass and better function is still discussed controversially. Nevertheless, EMS should not be regarded as a replacement of exercise training per se, since the beneficial effect of exercise training is not just relying on building muscle mass but it also exerts positive effects on endothelial, myocardial, and cognitive function.

Inhibition of xanthine oxidase reduces wasting and improves outcome in a rat model of cancer cachexia.

Cachexia is a common co-morbidity in cancer occurring in up to 80% of patients depending on the type of cancer. Uric acid (UA), the end-product of the purine metabolism, is elevated in cachexia due to tissue wasting and upregulated xanthine oxidase (XO) activity. High serum UA levels indicate increased XO-dependent production of oxygen free radicals (reactive oxygen species; ROS) and correlate with metabolic illness and poor survival. We hypothesized that XO-inhibition might reduce inflammatory signals accounting for tissue wasting and improve survival in experimental cancer cachexia. Animals were inoculated intraperitoneally with AH-130 hepatoma cells and treated with two XO-inhibitors: allopurinol [Allo, low (LD) and high dose (HD) 4 and 40 mg/kg/d] and its more effective active metabolite oxypurinol (Oxy, 4 and 40 mg/kg/d) or placebo for 15 days. Weight loss and tissue wasting of both fat and lean tissue (assessed by NMR-scanning) was reduced by both LD and HD Allo and LD-Oxy, but not by HD-Oxy. A robust induction of XO-activity for generation of reactive oxygen species was seen in the placebo group (assessed by electron paramagnetic spectroscopy), which was reduced by XO-inhibition. Increased ROS induced cytokine signaling, proteolytic activity and tissue degradation were all attenuated by XO inhibition. Survival was significantly and dose dependently improved. Food intake and spontaneous locomotor activity were higher, indicating a higher quality of life. Inhibition of XO can reduce tissue wasting and improve survival in cancer cachexia and clearly clinical studies are needed.

Impact of N-acetylcysteine on contrast-induced nephropathy defined by cystatin C in patients with ST-elevation myocardial infarction undergoing primary angioplasty.

BACKGROUND: The aim of this study was to assess the effects of N-acetylcysteine (N-ACC) on contrast-induced nephropathy (CIN) defined by Cystatin C (Cys-C) serum levels and to evaluate the influence of Cys-C on clinical outcome in patients with ST-elevation myocardial infarction (STEMI). METHODS: In total, 251 patients with STEMI undergoing primary percutaneous coronary intervention (PCI) were randomized to either high-dose N-ACC (2 × 1200 mg/d for 48 h) with optimal hydration or placebo plus optimal hydration. Serum Cys-C was measured at baseline, immediately, 24, 48 and 72 h after PCI. CIN was defined as an increase in serum Cys-C levels of 25% or more from baseline within 72 h after PCI. Major adverse cardiac events (MACE)--defined as death, recurrent infarction and congestive heart failure--within 6 months were recorded. RESULTS: Baseline Cys-C was 1294 ± 611 and 1352 ± 811 ng/mL (p = 0.54) for the N-ACC and placebo group, respectively. There was a steady increase in Cys-C in both groups within the first 72 h after randomization. CIN occurred in 74.6 and in 70.4% of patients in the N-ACC and placebo group, respectively (p = 0.46). The magnitude of increase in the serum concentration of Cys-C was an independent predictor for MACE after 6 months of follow-up. CONCLUSIONS: High-dose N-ACC does not provide additional benefit over placebo with respect to Cys-C defined CIN in STEMI patients undergoing primary PCI. The magnitude of increase in Cys-C serum levels in the early course after STEMI is a predictor of medium-term MACE.

High-dose rosuvastatin in chronic heart failure promotes vasculogenesis, corrects endothelial function, and improves cardiac remodeling--results from a randomized, double-blind, and placebo-controlled study.

BACKGROUND: The full impact of statins on patients with chronic heart failure (CHF) is unknown. Therefore, we aimed to evaluate the pleiotropic effects of rosuvastatin on vascular and tissue regeneration, its impact on endothelial function and hemodynamics in CHF. METHODS: Forty-two patients with CHF (LVEF 30±1%) were randomized to 12 weeks of oral rosuvastatin (40 mg/d) or placebo. At baseline and at 12 weeks, VEGF and oxidized LDL (oxLDL) were assessed by ELISA. Circulating endothelial progenitor cells (CPCs) were quantified using FACS. CPC function was determined by matrigel assay. Number of CD34(+) stem cells and capillary density were measured in skeletal muscle (SM). Flow-mediated dilatation (FMD) and left ventricular (LV) function were determined by ultrasound. RESULTS: Rosuvastatin increased VEGF by +43% (p=0.004 vs. placebo) and decreased oxLDL by -27% (p=0.04 vs. placebo). This was associated with an elevation in CPC count by +224% (p=0.04 vs. placebo) and an augmentation of CPC integrative capacity by +91% (p=0.03 vs. placebo). Capillary density increased by +14% (p<0.001 vs. placebo), which was associated with an enhanced homing of CD34(+) stem cells. Rosuvastatin improved FMD by +163% (p<0.001 vs. placebo) and enhanced ejection fraction by +27% (p<0.001 vs. placebo). CONCLUSION: In CHF, rosuvastatin activates CPCs that contribute to neovascularisation and to the enhancement of endothelial function. Correction of vascular abnormalities leads in part to an increase in LV function. Therefore, rosuvastatin's non-lipid effects may have the potential to promote endogenous tissue regeneration and improve LV performance in CHF.

Impact of high-dose N-acetylcysteine versus placebo on contrast-induced nephropathy and myocardial reperfusion injury in unselected patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention. The LIPSIA-N-ACC (Prospective, Single-Blind, Placebo-Controlled, Randomized Leipzig Immediate PercutaneouS Coronary Intervention Acute Myocardial Infarction N-ACC) Trial.

OBJECTIVES: The aim of this randomized, single-blind, controlled trial was to assess N-acetylcysteine effects on contrast-induced nephropathy and reperfusion injury in ST-segment elevation myocardial infarction patients undergoing primary angioplasty with moderate contrast volumes. BACKGROUND: High-dose N-acetylcysteine reduced the incidence of contrast-induced nephropathy in patients with high contrast volumes and reduced reperfusion injury in animal trials. METHODS: Patients undergoing primary angioplasty were randomized to either high-dose N-acetylcysteine (2 x 1,200 mg/day for 48 h; n = 126) or placebo plus optimal hydration (n = 125). The 2 primary end points were: 1) the occurrence of >25% increase in serum creatinine level <72 h after randomization; and 2) a reduction in reperfusion injury measured as myocardial salvage index by magnetic resonance imaging. RESULTS: The median volume of an iso-osmolar contrast agent during angiography was 180 ml (interquartile range [IQR] 140 to 230 ml) in the N-acetylcysteine and 160 ml (IQR 120 to 220 ml) in the placebo group (p = 0.20). The primary end point contrast-induced nephropathy occurred in 14% of the N-acetylcysteine group and in 20% of the placebo group (p = 0.28). The myocardial salvage index was also not different between both treatment groups (43.5; IQR 25.4 to 71.9 vs. 51.5; IQR 29.5 to 75.3; p = 0.36). Activated oxygen protein products and oxidized low-density lipoprotein as markers for oxidative stress were reduced by as much as 20% in the N-acetylcysteine group (p < 0.05), whereas no change was evident in the placebo group. CONCLUSIONS: High-dose intravenous N-acetylcysteine reduces oxidative stress. However, it does not provide an additional clinical benefit to placebo with respect to CIN and myocardial reperfusion injury in nonselected patients undergoing angioplasty with moderate doses of contrast medium and optimal hydration. (Myocardial Salvage and Contrast Dye Induced Nephropathy Reduction by N-Acetylcysteine [LIPSIA-N-ACC]; NCT00463749).

Effects of laser-induced thermotherapy (LITT) on proliferation and apoptosis of glioma cells in rat brain transplantation tumors.

BACKGROUND AND OBJECTIVES: Laser-induced thermotherapy (LITT) is an approach to the treatment of brain tumors especially in poorly accessible regions. Its clinical applicability with tumor cell destruction has been shown in several studies. However, no data are known about specific effects on tumors cells due to LITT in the time course of the lesion. STUDY DESIGN/MATERIALS AND METHODS: LITT was performed in adult Lewis rats with implanted glioma cells in the brain using a standard exposure of 3 W for 30 seconds. Before and following LITT, neoplastic lesions were monitored by MRI. Proliferation of implanted cells and gliosis were assessed by several histological techniques and immunohistochemistry. Apoptosis was detected by TUNEL staining. RESULTS: Our experiments show a destruction of neoplastic cells by LITT but surviving tumor cells at the margin of the lesion. Apoptosis was detected following LITT restricted to residual neoplastic cells. Marginal survival of tumor cells lead to a secondary outgrowth into the necrotic lesion adjacent to sprouting capillaries. CONCLUSIONS: LITT is a suitable technique for the treatment of brain neoplasms. However, further investigations are necessary to prevent tumor recurrences after LITT.