Dapagliflozin-entresto protected kidney from renal hypertension via downregulating cell-stress signaling and upregulating SIRT1/PGC-1α/Mfn2-medicated mitochondrial homeostasis

This study tested whether combined dapagliflozin and entresto would be superior to mere one therapy on protecting the residual renal function and integrity of kidney parenchyma in hypertensive kidney disease (HKD) rat. In vitro results showed that the protein expressions of oxidative-stress/mitochondrial-damaged (NOX-1/NOX-2/oxidized-protein/cytosolic-cytochrome-C)/apoptotic (mitochondrial-Bax/cleaved caspeases 3, 9)/cell-stress (p-ERK/p-JNK/p-p38) biomarkers were significantly increased in H2O2-treated NRK-52E cells than those of controls that were reversed by dapagliflozin or entresto treatment. Adult-male SD rats (n = 50) were equally categorized into group 1 (sham-operated-control), group 2 (HKD by 5/6 nephrectomy + DOCA-salt/25 mg/kg/subcutaneous injection/twice weekly), group 3 (HKD + dapagliflozin/orally, 20 mg/kg/day for 4 weeks since day 7 after HKD induction), group 4 (HKD + entresto/orally, 100 mg/kg/day for 4 weeks since day 7 after HKD induction), and group 5 (HKD + dapagliflozin + entresto/the procedure and treatment strategy were identical to groups 2/3/4). By day 35, circulatory levels of blood-urine-nitrogen (BUN)/creatinine and urine protein/creatinine ratio were lowest in group 1, highest in group 2, and significantly lower in group 5 than in groups 3/4, but no difference between groups 3/4. Histopathological findings showed the kidney injury score/fibrotic area/cellular expressions of oxidative-stress/kidney-injury-molecule (8-OHdG+/KIM-1+) exhibited an identical trend, whereas the cellular expressions of podocyte components (synaptopodin/ZO-1/E-cadherin) exhibited an opposite pattern of BUN level among the groups. The protein expressions of oxidative stress/mitochondrial-damaged (NOX-1/NOX-2/oxidized protein/cytosolic-cytochrome-C/cyclophilin-D)/apoptotic (mitochondrial-Bax/cleaved-caspase 3)/mitochondrial-fission (PINK1/Parkin/p-DRP1)/autophagic (LC3BII/LC3BI ratio, Atg5/beclin-1)/MAPK-family (p-ERK/p-JNK/p-p38) biomarkers displayed a similar pattern, whereas the protein expression of mitochondria-biogenesis signaling (SIRT1/PGC-1α-Mfn2/complex I-V) displayed an opposite pattern of BUN among the groups. In conclusion, combined dapagliflozin-entresto therapy offered additional benefits on protecting the residual kidney function and architectural integrity in HKD rat.

Combined therapy with dapagliflozin and entresto offers an additional benefit on improving the heart function in rat after ischemia-reperfusion injury

BACKGROUND

This study tested whether combined dapagliflozin and entresto treatment would be superior to either one alone for preserving the left-ventricular ejection-fraction (LVEF) in rat after ischemia-reperfusion (IR) injury.

METHODS AND RESULTS

In vitro flow-cytometric result showed that the intracellular and mitochondrial reactive oxygen species and mitochondrial permeability transition pore, and protein levels of oxidative-stress/DNA-damaged markers [NADPH-oxidase-1 (NOX-1)/NOX-2/oxidized-protein/γ-H2A-histone-family member X (γ-H2AX)] were significantly higher in hydrogen peroxide (H₂O₂) (300μM)-treated H9C2 cells as compared with the controls that were significantly reversed in sacubitril/valsartan and dapagliflozin therapy in the same H₂O₂-treated condition, whereas the protein expressions of antioxidants [Sirtuin-1 (SIRT1)/SIRT3/superoxide dismutase/catalase/glutathione peroxidase) exhibited an opposite pattern among the groups (all p<0.001). Adult-male-Sprague-Dawley rat (n=40) were equally categorized into group 1 (sham-operated control), group 2 (IR), group 3 (IR+dapagliflozin/20mg/kg/orally at 3h and post-days 1/2/3 after IR), group 4 (IR+entresto/100mg/kg/orally at 3h and post-days 1/2/3 after IR) and group 5 (IR+dapagliflozin+entresto) and the hearts were harvested by day 3 after IR. The 3^rd day's LVEF was highest in group 1, lowest in group 2 and significantly higher in group 5 than in groups 3/4, but it was similar between the latter two groups (p<0.001). The protein expressions of oxidative-stress (NOX-1/NOX-2/oxidized protein), fibrotic (transforming-growth factor-ß/phosphorylated-Smad3), apoptotic [mitochondrial-Bax/cleaved-caspase-3/cleaved-poly (ADP-ribose) polymerase], mitochondria/DNA damaged (cytosolic-cytochrome-C/γ-H2AX), pressure-overload/heart-failure [brain natriuretic peptide (BNP)/ß-myosin heavy chain] and autophagic (ratio of meiotic cyclins CLB3-II/CLB3-I) biomarkers, and the upstream (high-mobility group box 1/Toll-like receptor-4/MyD88/phosphorylated-nuclear factor-κB and downstream [interleukin (IL)-1ß/IL-6/tumor necrosis factor-α] inflammatory signalings revealed an antithetical features of LVEF among the groups (all p<0.0001). The cellular levels of inflammatory (myeloperoxidase+/CD68+), pressure-overload/heart-failure (BNP+) and DNA-damage (γ-H2AX+) biomarkers as well as infarct area demonstrated an opposite pattern of LVEF among the groups (all p<0.0001).

CONCLUSION

Incorporated entresto-dapagliflozin treatment was superior to either one alone on protecting the heart against IR injury.

Early treatment with combination of SS31 and entresto effectively preserved the heart function in doxorubicin-induced dilated cardiomyopathic rat

BACKGROUND

This study tested the hypothesis that early administration of SS31 and entresto (En) was superior to either one alone on preserving the heart function in setting of dilated cardiomyopathy (DCM) induced by doxorubicin (Dox) [accumulated dosage of 12.5 mg/kg/administered by intraperitoneal (IP) at 4 separated time points within 20 days] in rat.

METHODS AND RESULTS

Adult-male SD rats (n = 40) were equally categorized into groups 1 (sham-control), 2 (DCM), 3 (DCM + SS31/0.7 mg/kg/day/IP, since day-14 after DCM induction to day-60), 4 [DCM + En (30 mg/kg/day/orally since day-14 after DCM induction to day-60)] and 5 (DCM + combined SS31-En), and animals were euthanized by day 60. By day 60, left-ventricular ejection-fraction (LVEF) was highest in group 1, lowest in group 2 and significantly higher in group 5 than in groups 3 and 4 (all p < 0.0001), but it showed no difference between groups 3/4. The microscopic study showed that the fibrosis area/cardiomyocyte size and DNA-damaged (γ-H2AX+)/inflammatory (CD14+//CD68+) markers, and flow analysis of inflammatory (Ly6G+/MPO+/CD11^b/c+) and early/late apoptosis (AN-V⁺/PI^-//AN-V⁺/PI⁺) cells exhibited an opposite pattern of LVEF among the five groups (all p < 0.0001). The protein expressions of inflammatory upstream (TLR2/TLR4/MyD88/Mal/ TRAF6/IKK-α/IKK-ß) and downstream (p-NF-κb/TNF-α/IL-1ß/MMP-9), oxidative-stress/mitochondrial-damaged (NOX-1/NOX-2/cytosolic cytochrome-C/cyclophilin-D/DRP1) and autophagic/apoptotic (ratio of LC3B-II/LC3B-I and mitochondrial-Bax/caspase3/9) signaling pathways also exhibited an opposite pattern of LVEF among the five groups (all p < 0.0001).

CONCLUSION

Combined SS31-En therapy was superior to either one alone on protecting the heart structural and functional integrities against Dox-induced DCM damage.

Rationale for and Practical Use of Sacubitril/Valsartan in the Patient's Journey with Heart Failure and Reduced Ejection Fraction

Sacubitril with valsartan (sacubitril/valsartan) is a relatively novel compound that has become a milestone in the treatment of patients with chronic heart failure (HF) with reduced ejection fraction (HFrEF) in the last decade. Contemporary data suggest that sacubitril/valsartan is associated with improved outcomes compared with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, and has a greater beneficial effect on myocardial reverse remodelling. Additionally, two recent trials have shown that sacubitril/valsartan is well-tolerated even in the acute HF setting, thus enabling a continuum of use in the patient's journey with HFrEF. This article summarises available data on the effectiveness and tolerability of sacubitril/valsartan in patients with HFrEF, and provides the clinician with practical insights to facilitate the use of this drug in every setting, with an emphasis on acute HF, hypotension, electrolyte imbalance and renal insufficiency.

The Anti-Breast Cancer Effect and Mechanism of Glimepiride-Metformin Adduct

Background

Compound adduct is a eutectic crystal formed by non-covalent bonds of two compounds or multiple compounds with water. Emerging evidence suggests that adduct could be different from the simple physical mixture of the individual compounds and has some new features. Recent studies reported that both glimepiride (Gli) and metformin (Met) may possess an anti-breast cancer effect besides anti-diabetic effect. In the current study, we synthesized glimepiride-metformin adduct (GMA) and examined its anti-breast cancer effect in vitro and in vivo to explore its potential in treatment of breast cancer in diabetic patients.

Methods

GMA was synthesized from Gli, Met and water at a molar molecular mass of 1:1:1 and identified by infrared spectroscopy. MTT assay, colony formation assay and wound healing assay were performed to examine the effects of GMA on cell viability and migration of human breast cancer cell lines CAL-148, MDA-MB-453, MDA-MB-231and MCF-7. The effect of GMA on cell cycle and apoptosis was examined by flow cytometry. The orthotopic implantation model was established to observe the inhibitory effect of GMA on tumor growth. The expression of Ki67 was detected by immunohistochemistry. RT-qPCR and Western blotting were performed to investigate mechanisms for the function of GMA.

Results

Both MTT and colony formation assays showed that GMA inhibited breast cancer cell viability, and the effect was greater than Gli alone, Met alone and the combination. In vivo study showed that GMA had an inhibitory effect on tumor growth of CAL-148 xenografts. Flow cytometry analysis indicated that GMA induced G1/S phase cell cycle arrest and apoptosis in breast cancer cells. RT-qPCR and Western blotting analyses showed that GMA activated AMPK, and up-regulated expression of p53 and p21, and down-regulated expression of cyclin D1 and CDK4.

Conclusion

GMA suppresses cell viability of breast cancer cells, and its effect is greater than Gli and Met alone or combination at the same concentration. GMA inhibits breast cancer cell growth in vivo. The antitumor effect of GMA may be related to the activation of AMPK resulting in up-regulation of p53 and p21 and down-regulation of cyclin D1 and CDK4.

The combination of a neprilysin inhibitor (sacubitril) and angiotensin-II receptor blocker (valsartan) attenuates glomerular and tubular injury in the Zucker Obese rat

OBJECTIVE

Diabetic nephropathy (DN) is characterized by glomerular and tubulointerstitial injury, proteinuria and remodeling. Here we examined whether the combination of an inhibitor of neprilysin (sacubitril), a natriuretic peptide-degrading enzyme, and an angiotensin II type 1 receptor blocker (valsartan), suppresses renal injury in a pre-clinical model of early DN more effectively than valsartan monotherapy.

METHODS

Sixty-four male Zucker Obese rats (ZO) at 16 weeks of age were distributed into 4 different groups: Group 1: saline control (ZOC); Group 2: sacubitril/valsartan (sac/val) (68 mg kg^-1 day^-1; ZOSV); and Group 3: valsartan (val) (31 mg kg^-1 day^-1; ZOV). Group 4 received hydralazine, an anti-hypertensive drug (30 mg kg^-1 day^-1, ZOH). Six Zucker Lean (ZL) rats received saline (Group 5) and served as lean controls (ZLC). Drugs were administered daily for 10 weeks by oral gavage.

RESULTS

Mean arterial pressure (MAP) increased in ZOC (+ 28%), but not in ZOSV (- 4.2%), ZOV (- 3.9%) or ZOH (- 3.7%), during the 10 week-study period. ZOC were mildly hyperglycemic, hyperinsulinemic and hypercholesterolemic. ZOC exhibited proteinuria, hyperfiltration, elevated renal resistivity index (RRI), glomerular mesangial expansion and podocyte foot process flattening and effacement, reduced nephrin and podocin expression, tubulointerstitial and periarterial fibrosis, increased NOX2, NOX4 and AT₁R expression, glomerular and tubular nitroso-oxidative stress, with associated increases in urinary markers of tubular injury. None of the drugs reduced fasting glucose or HbA1c. Hypercholesterolemia was reduced in ZOSV (- 43%) and ZOV (- 34%) (p < 0.05), but not in ZOH (- 13%) (ZOSV > ZOV > ZOH). Proteinuria was ameliorated in ZOSV (- 47%; p < 0.05) and ZOV (- 30%; p > 0.05), but was exacerbated in ZOH (+ 28%; p > 0.05) (ZOSV > ZOV > ZOH). Compared to ZOC, hyperfiltration was improved in ZOSV (p < 0.05 vs ZOC), but not in ZOV or ZOH. None of the drugs improved RRI. Mesangial expansion was reduced by all 3 treatments (ZOV > ZOSV > ZOH). Importantly, sac/val was more effective in improving podocyte and tubular mitochondrial ultrastructure than val or hydralazine (ZOSV > ZOV > ZOH) and this was associated with increases in nephrin and podocin gene expression in ZOSV (p < 0.05), but not ZOV or ZOH. Periarterial and tubulointerstitial fibrosis and nitroso-oxidative stress were reduced in all 3 treatment groups to a similar extent. Of the eight urinary proximal tubule cell injury markers examined, five were elevated in ZOC (p < 0.05). Clusterin and KIM-1 were reduced in ZOSV (p < 0.05), clusterin alone was reduced in ZOV and no markers were reduced in ZOH (ZOSV > ZOV > ZOH).

CONCLUSIONS

Compared to val monotherapy, sac/val was more effective in reducing proteinuria, renal ultrastructure and tubular injury in a clinically relevant animal model of early DN. More importantly, these renoprotective effects were independent of improvements in blood pressure, glycemia and nitroso-oxidative stress. These novel findings warrant future clinical investigations designed to test whether sac/val may offer renoprotection in the setting of DN.

Sacubitril/valsartan therapeutic strategy in HFpEF: Clinical insights and perspectives

Sacubitril/valsartan represents the first of a new class of drugs able to act as a neprilysin inhibitor and as an angiotensin receptor blocker. This double inhibition has the advantage of concomitantly blocking a pro-fibrotic/pro-hypertrophic mechanism (angiotensin receptor blocker component) while stimulating an anti-fibrotic/anti-hypertrophic mechanism (neprilysin inhibitor component). Furthermore, the novel drug has natriuretic and diuretic properties, better preserves renal function, provides better blood pressure control as compared to renin angiotensin system inhibitors, and improves ventricular-arterial coupling. Consequently, sacubitril/valsartan provides greater target organ protection than angiotensin receptor blocker therapy alone, including cardiac, vascular, and renal protection. Up to now, this drug does not have an indication in patients with heart failure with preserved ejection fraction (HFpEF). However, its complex mechanism of action and previous experimental and clinical data seem to suggest its possible success in HFpEF. In this review we highlight and discuss the rationale, clinical insights, and perspectives behind the use of sacubitril/valsartan in HFpEF, specifically referring to its possible efficacy in pathophysiologic mechanisms, such as myocardial hypertrophy, fibrosis, and ischemia, renal dysfunction, impaired ventricular-arterial coupling, which are all tightly related to elevated left ventricular end diastolic pressure, a common hallmark for this multifaceted syndrome.

High performance thin-layer and high performance liquid chromatography coupled with photodiode array and fluorescence detectors for analysis of valsartan and sacubitril in their supramolecular complex with quantitation of sacubitril-related substance in raw material and tablets

Valsartan (VAL) and sacubitril (SAC) are combined in a supramolecular complex, LCZ696, which is a newly approved remedy for heart failure. SAC-related substance (biphenyl methyl pyrrolidinone [BMP]) which also appears as an intermediate during SAC synthesis is considered to be a suspected impurity for SAC and/or LCZ696 tablets. The study investigates the analysis of VAL and SAC in their supramolecular complex along with SAC-related substance, BMP, using high performance thin-layer chromatography (HPTLC) and high performance liquid chromatography (HPLC) with two different detectors; fluorescence detector (FLD) and diode array detector (DAD). The work aimed at analyzing BMP at low levels in the presence of its parent drug, SAC. BMP was successfully analyzed at a level of 0.167, 1 and 3% of its parent drug, SAC upon using HPLC-FLD, HPLC-DAD and HPTLC, respectively. For HPLC-FLD, the detector was set at λex/λem (nm/nm): 0-4.5 min at 255/374; 4.5-6 min at 255/314, for achieving an adequate sensitivity of the method to monitor and quantify VAL and SAC in the presence of BMP. Low limits of detection (8.3, 3.3 and 1.7 ng mL-1) and limits of quantitation (25, 10 and 5 ng mL-1) values obtained for VAL, SAC and BMP, respectively, upon using FLD suggest that low level of baseline noise enables the detection and quantitation of low BMP concentration.

Combined Angiotensin Receptor-Neprilysin Inhibitors Improve Cardiac and Vascular Function Via Increased NO Bioavailability in Heart Failure

Background

There is a paucity of data about the mechanisms by which sacubitril/valsartan (also known as LCZ696) improves outcomes in patients with heart failure. Specifically, the effects of sacubitril/valsartan on vascular function and NO bioavailability have not been investigated. We hypothesized that sacubitril/valsartan therapy increases circulating NO levels and improves vascular function in the setting of heart failure.

Methods and Results

Male spontaneously hypertensive rats underwent myocardial ischemia/reperfusion surgery to induce heart failure and were followed for up to 12 weeks with serial echocardiography. Rats received sacubitril/valsartan (68 mg/kg), valsartan (31 mg/kg), or vehicle starting at 4 weeks after reperfusion. At 8 or 12 weeks of reperfusion, animals were euthanized and tissues were collected for ex vivo analyses of NO bioavailability, aortic vascular reactivity, myocardial and vascular histology, and cardiac molecular assays. Left ventricular structure and function were improved by both valsartan and sacubitril/valsartan compared with vehicle. Sacubitril/valsartan resulted in superior cardiovascular benefits, as evidenced by sustained improvements in left ventricular ejection fraction and end‐diastolic pressure. Ex vivo vascular function, as measured by aortic vasorelaxation responses to acetylcholine and sodium nitroprusside, was significantly improved by valsartan and sacubitril/valsartan, with more sustained improvements afforded by sacubitril/valsartan. Furthermore, myocardial NO bioavailability was significantly enhanced in animals receiving sacubitril/valsartan therapy.

Conclusions

Sacubitril/valsartan offers superior cardiovascular protection in heart failure and improves vascular function to a greater extent than valsartan alone. Sacubitril/valsartan‐mediated improvements in cardiac and vascular function are likely related to increases in NO bioavailability and explain, in part, the benefits beyond angiotensin receptor blockade.

Neprilysin inhibition in heart failure: mechanisms and substrates beyond modulating natriuretic peptides

The autonomic nervous system, the renin-angiotensin-aldosterone system, and the natriuretic peptide system represent critical regulatory pathways in heart failure and as such have been the major targets of pharmacological development. The introduction and approval of angiotensin receptor neprilysin inhibitors (ARNi) have broadened the available drug treatments of patients with chronic heart failure with reduced ejection fraction. Neprilysin catalyses the degradation of a number of vasodilator peptides, including the natriuretic peptides, bradykinin, substance P, and adrenomedullin, as well as vasoconstrictor peptides, including endothelin-1 and angiotensin I and II. We review the multiple, potentially competing, substrates for neprilysin inhibition, and the resultant composite clinical effects of ARNi therapy. A mechanistic understanding of this novel therapeutic class may provide important insights into the expected on-target and off-target effects when this agent is more widely prescribed.

Protective Actions of H2S in Acute Myocardial Infarction and Heart Failure

Hydrogen sulfide (H2S) was identified as the third gasotransmitter in 1996 following the discoveries of the biological importance of nitric oxide and carbon monoxide. Although H2S has long been considered a highly toxic gas, the discovery of its presence and enzymatic production in mammalian tissues supports a critical role for this physiological signaling molecule. H2S is synthesized endogenously by three enzymes: cystathionine β-synthase, cystathionine-γ-lyase, and 3-mercaptopyruvate sulfurtransferase. H2S plays a pivotal role in the regulation of cardiovascular function as H2S has been shown to modulate: vasodilation, angiogenesis, inflammation, oxidative stress, and apoptosis. Perturbation of endogenous production of H2S has been associated with many pathological conditions of the cardiovascular system such as diabetes, heart failure, and hypertension. As such, modulation of the endogenous H2S signaling pathway or administration of exogenous H2S has been shown to be cytoprotective. This review article will provide a summary of the current body of evidence on the role of H2S signaling in the setting of myocardial ischemia and heart failure. © 2017 American Physiological Society. Compr Physiol 7:583-602, 2017.