Abstract 231: Bendavia, a Novel Mitochondria-Targeting Peptide, Improves Contraction and Relaxation of Failing Cardiomyocytes Isolated From Dogs With Chronic Heart Failure

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Hani N Sabbah ◽  
Ramesh C Gupta
Keyword(s):  
Heart Failure ◽  
Atp Synthesis ◽  
Electrical Field Stimulation ◽  
Lv Function ◽  
Shortening Velocity ◽  
Cell Contractility ◽  
Targeting Peptide ◽  
Reduced Rate ◽  
Systolic And Diastolic Function ◽  
Mitochondria Targeting

Background: Mitochondria (MITO) of humans and dogs with heart failure (HF) manifest functional abnormalities characterized by poor respiration, reduced rate of ATP synthesis and increased production of reactive oxygen species (ROS) that adversely impact LV systolic and diastolic function. We previously showed that chronic therapy with Bendavia (BEN, MTP-131), a novel mitochondria-targeting peptide, improves global LV function in dogs with HF without affecting heart rate or blood pressure. This improvement was associated with a reversal of MITO abnormalities and normalization of rate of ATP synthesis. This study tested the hypothesis that the improvement in global LV function seen in dogs with HF during treatment with BEN results primarily from enhanced function of constituent LV cardiomyocytes. Methods: Cardiomyocytes were isolated from the LV free wall of 8 untreated dogs with coronary microembolization-induced HF (LV ejection fraction <30%). A collagenase-based enzymatic process was used for the isolation and yielded ~70% viable rod-shaped cardiomyocytes that excluded trypan blue. Extent of cardiomyocytes shortening, shortening velocity and lengthening velocity were assessed during 1.0 Hz electrical field stimulation delivered via a MyoPacer (ION Optix). Measurements were made at baseline and were repeated after one hour of gradual exposure of the same cardiomyocytes to BEN at a concentration of 0.1 μM. Results: At baseline, the extent of cardiomyocyte shortening was 3.7 ± 0.8 μm, shortening velocity was 62.8 ± 16.9 μm /sec and lengthening velocity was -53.8 ± 16.5 μm/sec. Exposure of cardiomyocyte to BEN significantly increased the extent of cardiomyocyte shortening to 5.4 ± 1.1 μm (p<0.012), shortening velocity to 94.5 ± 21.9 μm/sec (p<0.020) and lengthening velocity to -96.8 ± 21.1 μm/sec (p<0.016) compared to baseline. Conclusions: Exposure of failing isolated cardiomyocytes to BEN elicits improvements in the rate of cardiomyocyte shortening and re-lengthening indicative of improved cell contractility and relaxation. This improvement is likely mediated by increased availability of ATP along with reduced ROS production both secondary to improved mitochondrial function elicited by treatment with BEN.

Abstract 90: Bendavia (MTP-131), a Novel Mitochondria-Targeting Peptide, Improves ADP-Stimulated Mitochondrial Respiration in Cardiomyocytes Isolated From Dogs with Chronic Heart failure

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Hani Sabbah ◽  
Ramesh C Gupta ◽  
Sharad Rastogi ◽  
Paula Mohyi ◽  
Kristina Szekely
Keyword(s):  
Heart Failure ◽  
Mitochondrial Respiration ◽  
Systolic Function ◽  
Atp Synthesis ◽  
Vehicle Control ◽  
Electrode System ◽  
Lv Function ◽  
Targeting Peptide ◽  
Lv Systolic Function ◽  
Mitochondria Targeting

Background: Mitochondria (MITO) of failed human hearts and hearts of dogs with experimental heart failure (HF) manifest structural and functional abnormalities characterized by hyperplasia and reduced organelle size and reduced respiration. These abnormalities lead to reduced ATP synthesis that adversely impacts LV function. We previously showed that chronic therapy (3 months) with Bendavia (MTP-131), a novel mitochondria-targeting peptide, improves LV systolic function in dogs with heart failure (HF), reverses MITO abnormalities and normalizes mitochondria ATP synthesis in myocardium from Bendavia-treated HF dogs. In the present study we examined the direct effects of Bendavia on mitochondria ADP-stimulated state 3 respiration in freshly isolated cardiomyocytes from dogs with advanced chronic HF. Methods: Cardiomyocytes were isolated from LV free wall of 3 untreated dogs with HF produced by intracoronary microembolizations (LV ejection fraction <30%). A standard collagenase-based enzymatic process was used for isolation that yielded ~70% viable rod-shaped cardiomyocytes that excluded trypan blue. Equal aliquotes of cardiomyocytes were incubated in 0, 0.01, 0.10, 1.0 and 10 μM concentration of Bendavia for one hour at 37°C. At the end of incubation, ADP-stimulated state-3 respiration was measured using a Clark electrode system and quatified in nAtom Oxygen/min/mg protein. Results: State-3 respiration in the absence of Bendavia (Vehicle-Control) was 248±9 nAtom Oxygen/min/mg protein. Compared to vehicle-control, incubation of failing cardiomyocytes with Bendavia significantly increased state-3 respiration to 303±33 at 0.01 μM, p<0.05; 405±39 at 0.10 μM, p<0.05; 371±28 at 1.0 μM, p<0.05; and 346±29 at 10.0 μM, p<0.05. Conclusions: Results of this study indicate that the effects of Bendavia on mitochondrial respiration in cardiomyocytes is direct and not a consequence of improved global LV structure or function. Furthermore, the results indicate that the improvement in mitochondrial respiration after treatment with Bendavia can occur early after initiation of therapy (within one hour) and is dose-dependent up to concentrations of 0.10 μM.

Abstract 090: Long-term Therapy with a Bendavia (MTP-131), a Novel Mitochondria-Targeting Peptide, Normalizes Cardiolipin Biosynthesis and Remodeling in Left Ventricular Myocardium of Dogs with Advanced Heart Failure

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Hani N Sabbah ◽  
Quan He ◽  
Ramesh C Gupta ◽  
Sharad Rastogi ◽  
Mengjun Wang ◽  
...  
Keyword(s):  
Heart Failure ◽  
Atp Synthesis ◽  
Left Ventricular ◽  
Advanced Heart Failure ◽  
Term Therapy ◽  
Complex Iv ◽  
Targeting Peptide ◽  
Long Term Therapy ◽  
Mitochondria Targeting

Background: Cardiolipin (CL) is a signature phospholipid of the mitochondrial inner membrane and responsible for modulation of activities of various enzymes essential for oxidative phosphorylation. Cardiac CL is biosynthesized in a series of steps from phosphatidic acid and remodeled into a form which contains four 18:2 fatty acid chains, tetralinoleol CL [(18:2) 4 CL]. Long-term therapy with Bendavia (MTP-131), a novel mitochondria-targeting peptide, was previously shown to improve left ventricular (LV) function, increase ATP synthesis, and increase the activity and protein levels of mitochondria cytochrome c oxidase (complex IV) in LV myocardium of dogs with advanced heart failure (HF). This study examined the effects of Bendavia on total CL and (18:2) 4 CL in LV myocardium of dogs with HF. Methods: LV tissue was obtained from 12 dogs with microembolization-induced HF randomized to 3 months therapy with subcutaneous injections of Bendavia (0.5 mg/kg once daily, n=7) or saline (Control, n=7). LV tissue from 7 normal dogs was used for comparison. Total CL and (18:2) 4 CL were measured using electrospray ionization mass spectroscopy and quantified in nmol/mg of non-collagen protein (NCP). Results: Total CL was significantly decreased in LV myocardium of Control dogs compared to normal dogs (19.1±1.1 vs. 26.7±1.4 nmol/mg, p<0.05) as was (18:2) 4 CL (14.2±0.9 vs. 20.5±1.2 nmol/mg, p<0.05). Long-term therapy with Bendavia significantly increased both total CL (23.6±1.1 nmol/mg) and (18:2) 4 CL (17.8±1.0 nmol/mg) to near normal levels in LV myocardium of treated HF dogs compared to untreated HF Controls (p<0.05). Conclusions: Total CL and (18:2) 4 CL are decreased in LV myocardium of dogs with HF. Treatment with Bendavia normalizes total CL and (18:2) 4 CL. These findings are consistent with observed normalization of mitochondrial complex IV activity, normalization of rate of ATP synthesis and improvement of global LV performance in dogs with HF after long-term therapy with Bendavia.

scholarly journals Effects of a myofilament calcium sensitizer on left ventricular systolic and diastolic function in rats with volume overload heart failure

2014 ◽  
Vol 307 (11) ◽  
pp. H1605-H1617 ◽  
Author(s):  
Kristin Wilson ◽  
Anuradha Guggilam ◽  
T. Aaron West ◽  
Xiaojin Zhang ◽  
Aaron J. Trask ◽  
...  
Keyword(s):  
Heart Failure ◽  
Troponin I ◽  
Regulatory Protein ◽  
Volume Overload ◽  
Left Ventricular ◽  
Lv Function ◽  
Stroke Work ◽  
Sprague Dawley ◽  
Diastolic Relaxation ◽  
Systolic And Diastolic Function

Aortocaval fistula (ACF)-induced volume overload (VO) heart failure (HF) results in progressive left ventricular (LV) dysfunction. Hemodynamic load reversal during pre-HF (4 wk post-ACF; REV) results in rapid structural but delayed functional recovery. This study investigated myocyte and myofilament function in ACF and REV and tested the hypothesis that a myofilament Ca2+ sensitizer would improve VO-induced myofilament dysfunction in ACF and REV. Following the initial sham or ACF surgery in male Sprague-Dawley rats (200–240 g) at week 0, REV surgery and experiments were performed at weeks 4 and 8, respectively. In ACF, decreased LV function is accompanied by impaired sarcomeric shortening and force generation and decreased Ca2+ sensitivity, whereas, in REV, impaired LV function is accompanied by decreased Ca2+ sensitivity. Intravenous levosimendan (Levo) elicited the best inotropic and lusitropic responses and was selected for chronic oral studies. Subsets of ACF and REV rats were given vehicle (water) or Levo (1 mg/kg) in drinking water from weeks 4–8. Levo improved systolic (% fractional shortening, end-systolic elastance, and preload-recruitable stroke work) and diastolic (τ, dP/d tmin) function in ACF and REV. Levo improved Ca2+ sensitivity without altering the amplitude and kinetics of the intracellular Ca2+ transient. In ACF-Levo, increased cMyBP-C Ser-273 and Ser-302 and cardiac troponin I Ser-23/24 phosphorylation correlated with improved diastolic relaxation, whereas, in REV-Levo, increased cMyBP-C Ser-273 phosphorylation and increased α-to-β-myosin heavy chain correlated with improved diastolic relaxation. We concluded that Levo improves LV function, and myofilament composition and regulatory protein phosphorylation likely play a key role in improving function.

Abstract 232: Bendavia, a Novel Mitochondria Targeting Peptide, Improves Mitochondrial Function in Circulating Blood Monocytes From Dogs With Chronic Heart Failure

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Hani N Sabbah ◽  
Vinita Sing-Gupta ◽  
Ramesh C Gupta
Keyword(s):  
Heart Failure ◽  
Atp Synthesis ◽  
Proton Leak ◽  
Blood Monocytes ◽  
Consumption Rates ◽  
Presence And Absence ◽  
Targeting Peptide ◽  
Dose Dependent Decrease ◽  
Measure Oxygen Consumption ◽  
Dose Dependent

Background: Mitochondrial (MITO) function is abnormal in heart failure (HF) as evidenced by reduced MITO respiration and rate of ATP synthesis. We showed that MITO dysfunction can be normalized in HF dogs after therapy with Bendavia (BEN), a novel MITO targeting peptide. This study tested the hypothesis that BEN will also reverse abnormalities of MITO function present in blood monocytes (MCs) of HF dogs. Methods: Blood samples obtained from 6 normal (NL) dogs and 6 dogs with coronary microembolizations-induced HF (LV ejection fraction ~30%) were used to isolate MCs by sequential Ficoll and Percoll density gradients. An XFe/XF96 analyzer (Seahorse Bioscience) was used to measure oxygen consumption rates (OCR) in MCs in the presence and absence of 1 μM oligomycin, 0.5 μM FCCP, or 1 μM each rotenone and antimycin. MITO proton leak, maximal respiration (MAXresp) and spare respiratory capacity (SRC) were measure in the presence and absence of 0.1, 1.0 and 10 μM concentrations of BEN and results expressed in pmols OCR/min/μg protein. Results: Proton leak, MAXresp and SRC were abnormal in MCs of HF dogs compared to NL. Incubation with BEN had no effect on measures of MCs MITO function of NL dogs but nearly normalized MITO function of MCs of HF dogs as evidenced by a dose-dependent increase MAXresp and SRC and dose-dependent decrease in proton leak (Table). Conclusions: MITO function is abnormal in blood MCs of HF dogs. BEN had no effect on MITO function of MCS from NL dogs but normalized MITO function in MCs from HF dogs. These findings support the use of circulating blood MCs as means of assessing MITO dysfunction in HF and as a marker of potential benefits derived from treatment with MITO targeted therapies.

scholarly journals Novel Mitochondria-Targeting Peptide in Heart Failure Treatment

2017 ◽  
Vol 10 (12) ◽  
Author(s):  
Melissa A. Daubert ◽  
Eric Yow ◽  
Gary Dunn ◽  
Sotir Marchev ◽  
Huiman Barnhart ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Failure Treatment ◽  
Failure Treatment ◽  
Targeting Peptide ◽  
Mitochondria Targeting
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