Linagliptin Suppresses Electrical and Structural Remodeling in the Isoproterenol Induced Myocardial Injury Model

Interleukin-6 Elevation Is a Key Pathogenic Factor Underlying COVID-19-Associated Heart Rate-Corrected QT Interval Prolongation

Background

Heart rate-corrected QT interval (QTc) prolongation is prevalent in patients with severe coronavirus disease 2019 (COVID-19) and is associated with poor outcomes. Recent evidence suggests that the exaggerated host immune-inflammatory response characterizing the disease, specifically interleukin-6 (IL-6) increase, may have an important role, possibly via direct effects on cardiac electrophysiology. The aim of this study was to dissect the short-term discrete impact of IL-6 elevation on QTc in patients with severe COVID-19 infection and explore the underlying mechanisms.

Methods

We investigated the following mechanisms: (1) the QTc duration in patients with COVID-19 during the active phase and recovery, and its association with C-reactive protein (CRP) and IL-6 levels; (2) the acute impact of IL-6 administration on QTc in an in vivo guinea pig model; and (3) the electrophysiological effects of IL-6 on ventricular myocytes in vitro.

Results

In patients with active severe COVID-19 and elevated IL-6 levels, regardless of acute myocardial injury/strain and concomitant QT-prolonging risk factors, QTc was significantly prolonged and rapidly normalized in correlation with IL-6 decrease. The direct administration of IL-6 in an in vivo guinea pig model acutely prolongs QTc duration. Moreover, ventricular myocytes incubated in vitro with IL-6 show evident prolongation in the action potential, along with significant inhibition in the rapid delayed rectifier potassium current (I_Kr).

Conclusion

For the first time, we demonstrated that in severe COVID-19, systemic inflammatory activation can per se promote QTc prolongation via IL-6 elevation, leading to ventricular electric remodeling. Despite being transitory, such modifications may significantly contribute to arrhythmic events and associated poor outcomes in COVID-19. These findings provide a further rationale for current anti-inflammatory treatments for COVID-19, including IL-6-targeted therapies.

Combination of Linagliptin and Empagliflozin Preserves Cardiac Systolic Function in an Ischemia-Reperfusion Injury Mice With Diabetes Mellitus

Background

Sodium-glucose co-transporter 2 inhibitor (SGLT2i) and dipeptidyl peptidase 4 inhibitor (DPP4i) are oral hypoglycemic agents. Although SGLT2i has been shown having the beneficial effects on heart failure in basic and clinical studies, the combined effects of SGLT2i and DPP4i have not been established well. We investigated the effects of SGLT2i and DPP4i against diabetes mice model of myocardial ischemia-reperfusion injury.

Methods

Streptozotocin-induced diabetic C57BL/6J mice were divided into control (vehicle), empagliflozin (30 mg/kg/day), linagliptin (3 mg/kg/day) and combination (30 mg/kg/day and 3 mg/kg/day, respectively) groups. After 7 days of drug administration, 30 min of myocardial ischemia was performed. We investigated body weight, heart weight, blood glucose, and cardiac functions by pressure-volume Millar catheter followed by 28 days of additional drug administration.

Results

Blood glucose levels, body weight, and heart weight were not significantly different between the groups. In Millar catheter analysis, left ventricular volume at the peak left ventricular ejection rate which is one of the cardiac systolic parameters in combination group was significantly preserved than that in control (P = 0.036). The cardiac index in the combination group tended to be preserved compared to that in the control (P = 0.06). The pathological fibrotic area in the left ventricle in the combination group also tended to be smaller (P = 0.08).

Conclusions

Combination therapy with linagliptin and empagliflozin preserved cardiac systolic function on the diabetes mice model of myocardial ischemia-reperfusion injury independent of blood glucose levels.

Selective targeting of ubiquitination and degradation of PARP1 by E3 ubiquitin ligase WWP2 regulates isoproterenol-induced cardiac remodeling

The elevated expression of poly(ADP-ribose) polymerase-1 (PARP1) and increased PARP1 activity, namely, poly(ADP-ribosyl)ation (PARylation), have been observed in cardiac remodeling, leading to extreme energy consumption and myocardial damage. However, the mechanisms underlying the regulation of PARP1 require further study. WWP2, a HECT-type E3 ubiquitin ligase, is highly expressed in the heart, but its function there is largely unknown. Here, we clarified the role of WWP2 in the regulation of PARP1 and the impact of this regulatory process on cardiac remodeling. We determined that the knockout of WWP2 specifically in myocardium decreased the level of PARP1 ubiquitination and increased the effects of isoproterenol (ISO)-induced PARP1 and PARylation, in turn aggravating ISO-induced myocardial hypertrophy, heart failure, and myocardial fibrosis. Similar findings were obtained in a model of ISO-induced H9c2 cells with WWP2 knockdown, while the reexpression of WWP2 significantly increased PARP1 ubiquitination and decreased PAPR1 and PARylation levels. Mechanistically, coimmunoprecipitation results identified that WWP2 is a novel interacting protein of PARP1 and mainly interacts with its BRCT domain, thus mediating the degradation of PARP1 through the ubiquitin-proteasome system. In addition, lysine 418 (K418) and lysine 249 (K249) were shown to be of critical importance in regulating PARP1 ubiquitination and degradation by WWP2. These findings reveal a novel WWP2-PARP1 signal transduction pathway involved in controlling cardiac remodeling and may provide a basis for exploring new strategies for treating heart disorders related to cardiac remodeling.

Safety, tolerability, pharmacokinetics and pharmacodynamics of parenterally administered dutogliptin: A prospective dose-escalating trial

Aims

Animal studies suggest that inhibition of dipeptidyl peptidase 4 (DPP‐IV) may improve heart function and survival after myocardial infarction by increasing cardiac myocytes’ regenerative capacity. Parenterally administered dutogliptin may provide continuous strong DPP‐IV inhibition to translate these results into humans. This trial investigated the safety and tolerability, as well as pharmacokinetics and pharmacodynamics, of parenterally administered dutogliptin after single and repeated doses.

Methods

In an open‐label trial, volunteers received dutogliptin at increasing doses of 30–120 mg subcutaneously or 30 mg intravenously in the single‐dose cohorts. Subjects in the multiple‐dose cohort received 60, 90 or 120 mg dutogliptin subcutaneously once daily on 7 consecutive days.

Results

Forty healthy males were included in the trial. No related serious adverse events occurred. Mild local injection site reactions with no requirement for intervention comprised 147 of 153 (96%) related adverse events. Subcutaneous bioavailability was approximately 100%. Multiple injections at daily intervals did not lead to the accumulation of the study drug. The accumulation ratios based on AUC_0‐24h range from 0.90 to 1.03, supporting this argument. All subjects receiving ≥60 mg dutogliptin yielded a maximum DPP‐IV inhibition >90%. The duration of DPP‐IV inhibition over time increased in a dose‐dependent manner and was highest in the 120‐mg multiple‐dosing cohort with a maximum AUEC_0‐24h of 342 h % (standard deviation: 73), translating into 86% DPP‐IV inhibition 24 hours after dosing.

Conclusion

Parenteral injection of dutogliptin was safe and subcutaneous bioavailability is excellent. DPP‐IV inhibition increased dose dependently to >86% over 24 hours after multiple doses of 120 mg dutogliptin.

Vildagliptin, a DPP-4 Inhibitor, Attenuates Endothelial Dysfunction and Atherogenesis in Nondiabetic Apolipoprotein E-Deficient Mice

Dipeptidyl peptidase-4 (DPP-4) inhibitors are novel antidiabetic agents with possible vascular protection effects. Endothelial dysfunction is an initiation step in atherogenesis. The purpose of this study was to investigate whether vildagliptin (Vilda) attenuates the development of endothelial dysfunction and atherosclerotic lesions in nondiabetic apolipoprotein E-deficient (ApoE^-/-) mice. Eight-week-old nondiabetic ApoE^-/- mice fed a Western-type diet received Vilda (50 mg/kg/day) for 20 weeks or 8 weeks. After 20 weeks of treatment, Vilda administration reduced atherogenesis in the aortic arch as determined by en face Sudan IV staining compared with the vehicle group (P < 0.05). Vilda also reduced lipid accumulation (P < 0.05) and vascular cell adhesion molecule-1 (VCAM-1) expression (P < 0.05) and tended to decrease macrophage infiltration (P = 0.05) into atherosclerotic plaques compared with vehicle. After 8 weeks of treatment, endothelium-dependent vascular reactivity was examined. Vilda administration significantly attenuated the impairment of endothelial function in nondiabetic ApoE^-/- mice compared with the vehicle group (P < 0.05). Vilda treatment did not alter metabolic parameters, including blood glucose level, in both study protocols. To investigate the mechanism, aortic segments obtained from wild-type mice were incubated with exendin-4 (Ex-4), a glucagon-like peptide-1 (GLP-1) analog, in the presence or absence of lipopolysaccharide (LPS). Ex-4 attenuated the impairment of endothelium-dependent vasodilation induced by LPS (P < 0.01). Furthermore, Ex-4 promoted phosphorylation of eNOS at Ser1177 which was decreased by LPS in human umbilical endothelial cells (P < 0.05). Vilda inhibited the development of endothelial dysfunction and prevented atherogenesis in nondiabetic ApoE^-/- mice. Our results suggested that GLP-1-dependent amelioration of endothelial dysfunction is associated with the atheroprotective effects of Vilda.

Cardio protective role of wogonin loaded nanoparticle against isoproterenol induced myocardial infarction by moderating oxidative stress and inflammation

Wogonin, one of the main active ingredients of Scutellaria radix, is a kind of flavonoid compound. In the present study, we report that wogonin nanoparticles (Wog np) protect Isoproterenol (ISO) induced Myocardial Infarction (MI) rats. Nanoparticles of sizes less than 200 nm with spherical shape were prepared using Polylactic-co-glycolic acid (PLGA) and Polyvinyl alcohol (PVA) respectively as polymer and stabilizer. Male Wistar rats were divided into 4 groups. Group 1 as a control group administered with physiological saline solution with 0.5 % carboxymethylcellulose (1 mL/day). Group 2 served as toxic group; rats received physiological saline solution with 0.5 % carboxymethylcellulose (1 mL/day) orally for 21 days Groups 3 and 4 received Wog np (25 and 50 mg/kg/day) orally for 21 days and on the 20th and 21 st days group 2, 3, and 4 were administered with ISO (85 mg/kg) through s.c. route at 24 h interval. pre-treatment with Wog np (25 and 50 mg/kg) could significantly reduce the cardiac infarct size, serum cardiac markers, lipid peroxidation product (MDA) and inflammatory markers as well as markedly upregulated the protein expression of nuclear factor erythroid 2-related factor (Nrf2)and heme oxygenase-1 (HO-1) to confer its strong cardioprotective activity against ISO induced myocardial damage.