PARP-Inhibitor Treatment Prevents Hypertension Induced Cardiac Remodeling by Favorable Modulation of Heat Shock Proteins, Akt-1/GSK-3beta and Several PKC Isoforms.

Spontaneously hypertensive rat (SHR) is a suitable model for studies of the complications of hypertension. It is known that activation of poly(ADP-ribose) polymerase enzyme (PARP) plays an important role in the development of postinfarction as well as long-term hypertension induced heart failure. In this study, we examined whether PARP-inhibitor (L-2286) treatment could prevent the development of hypertensive cardiopathy in SHRs. 6-week-old SHR animals were treated with L-2286 (SHR-L group) or placebo (SHR-C group) for 24 weeks. Wistar-Kyoto rats were used as aged-matched, normotensive controls (WKY group). Echocardiography was performed, brain-derived natriuretic peptide (BNP) activity and blood pressure were determined at the end of the study. We detected the extent of fibrotic areas. The amount of heat-shock proteins (Hsps) and the phosphorylation state of Akt-1Ser473, glycogen synthase kinase (GSK)-3betaSer9, forkhead transcription factor (FKHR)Ser256, mitogen activated protein kinases (MAPKs), and protein kinase C (PKC) isoenzymes were monitored. The elevated blood pressure in SHRs was not influenced by PARP-inhibitor treatment. Systolic left ventricular function and BNP activity did not differ among the three groups. L-2286 treatment decreased the marked left ventricular (LV) hypertrophy which was developed in SHRs. Interstitial collagen deposition was also decreased by L-2286 treatment. The phosphorylation of extracellular signal-regulated kinase (ERK)1/2Thr183-Tyr185, Akt-1Ser473, GSK-3betaSer9, FKHRSer256, and PKC epsilonSer729 and the level of Hsp90 were increased, while the activity of PKC alpha/betaIIThr638/641, zeta/lambda410/403 were mitigated by L-2286 administration. We could detect signs of LV hypertrophy without congestive heart failure in SHR groups. This alteration was prevented by PARP inhibition. Our results suggest that PARP-inhibitor treatment has protective effect already in the early stage of hypertensive myocardial remodeling

A citokeratin-18 sejthalálmarker vizsgálata sikeres cardiopulmonalis resuscitatión átesett betegpopulációban = The prognostic value of cytokeratin-18 cell death marker in cardiac arrest survivors

Absztrakt: Bevezetés: Citokeratin-18 (CK-18) az újraélesztés kapcsán kialakuló ischaemiás-reperfúziós károsodás kiváltotta teljes sejthalál során kerül a véráramba. Kaszpázok által hasított formája specifikus az apoptózis folyamatára. A markerek számos kórképben prognosztikus értékűnek bizonyultak. Tanulmányunkban elsőként vizsgáltuk prognosztikus értéküket reanimált betegpopulációban. Módszer: 40, sikeresen újraélesztett betegnél határoztuk meg a sejthalálmarkerek szintjét 6 órán belül, 24 és 72 óra múlva. Ezeket összevetettük a 30 napos túléléssel, a neurológiai kimenetellel, a szervfunkciós károsodást jellemző laboratóriumi, fizikális és terápiás jellemzőkkel, valamint a reanimáció körülményeivel. Eredmények: A reanimált betegek CK-18-plazmakoncentrációja a szakirodalomban leírt egészséges, posztoperatív és szeptikus populáció értékeinek a többszöröse volt (3842 vs. 242; 559; 1644 ng/l); a hasított és intakt CK-18 aránya alacsonyabb volt (0,14 vs. 0,58; 0,22; 0,24), ami jelentős sejtkárosodásra és a nekrózis dominanciájára utal. A markerek szintje azonban nem mutatott összefüggést a túléléssel, a neurológiai statusszal és a reanimáció körülményeivel sem. Veseelégtelenség esetén a CK-18 szintjének csökkenése elmaradt. Szignifikáns negatív korrelációt figyeltünk meg a 6 órás hemoglobin- és CK-18-szint között (r = –0,400, p<0,01), a 30 napos túlélésnek mégis az alacsonyabb hemoglobinértékek kedveztek. Következtetés: Várakozásunkkal ellentétben a vizsgált markerek nem bírtak prognosztikus értékkel újraélesztett betegpopulációban. A kimenetelt valószínűleg nem a teljes sejtkárosodás, hanem egy kisebb, a fenti markerekkel szenzitíven nem vizsgálható kritikus szerepű sejtpopuláció károsodása, valamint a beteg tartalékkapacitásai befolyásolják. Orv Hetil. 2020; 161(1): 26–32. | Abstract: Introduction: Cytokeratin-18 (CK-18) is releasing into the blood during systemic cell death due to ischemia-reperfusion injury after cardiac arrest. Its caspase-cleaved form is specific to apoptosis. Previous investigations proved their prognostic value in different conditions. We firstly investigated the prognostic value of these markers after cardiac arrest. Method: Plasma samples of 40 resuscitated patients were collected 6, 24, and 72 hours after successful resuscitation to determine the marker concentrations. We investigated the association of the markers with the 30-day mortality, neurological outcome, circumstances of the cardiac arrest, laboratory and physical parameters. Results: Resuscitated patients had highly elevated CK-18 levels (3842 vs. 242; 559; 1644 ng/L) and decreased caspase-cleaved CK-18/CK-18 ratio (0.14 vs. 0.58; 0.22; 0.24) compared to healthy subjects, septic and postoperative patients suggesting severe grade of cell death, mainly necrosis. Neither the marker concentrations nor their kinetics showed difference between survivors and non-survivors. They did not show association with the length of the resuscitation, the initial rhythm or the neurological outcome either. CK-18 decreased in patients with good renal function in contrast to patients with renal failure. Significant negative correlation was observed between the 6-hour cytokeratin-18 and hemoglobin concentrations (r = –0.400, p<0.01), while the 30-day survival was associated with lower hemoglobin levels. Conclusion: Surprisingly the biomarkers did not show prognostic value among resuscitated population. The outcome is probably not determined by the complete cell damage, but the loss of a small group of cells with critical role and the reserve capacity of the patient. Orv Hetil. 2020; 161(1): 26–32

A quinazoline-derivative compound with PARP inhibitory effect suppresses hypertension-induced vascular alterations in spontaneously hypertensive rats

AbstractAimsOxidative stress and neurohumoral factors play important role in the development of hypertension-induced vascular remodeling, likely by disregulating kinase cascades and transcription factors. Oxidative stress activates poly(ADP-ribose)-polymerase (PARP-1), which promotes inflammation and cell death. We assumed that inhibition of PARP-1 reduces the hypertension-induced adverse vascular changes. This hypothesis was tested in spontaneously hypertensive rats (SHR).Methods and resultsTen-week-old male SHRs and wild-type rats received or not 5mg/kg/day L-2286 (a water-soluble PARP-inhibitor) for 32weeks, then morphological and functional parameters were determined in their aortas. L-2286 did not affect the blood pressure in any of the animal groups measured with tail-cuff method. Arterial stiffness index increased in untreated SHRs compared to untreated Wistar rats, which was attenuated by L-2286 treatment. Electron and light microscopy of aortas showed prominent collagen deposition, elevation of oxidative stress markers and increased PARP activity in SHR, which were attenuated by PARP-inhibition. L-2286 treatment decreased also the hypertension-activated mitochondrial cell death pathway, characterized by the nuclear translocation of AIF. Hypertension activated all three branches of MAP-kinases. L-2286 attenuated these changes by inducing the expression of MAPK phosphatase-1 and by activating the cytoprotective PI-3-kinase/Akt pathway. Hypertension activated nuclear factor-kappaB, which was prevented by PARP-inhibition via activating its nuclear export.ConclusionPARP-inhibition has significant vasoprotective effects against hypertension-induced vascular remodeling. Therefore, PARP-1 can be a novel therapeutic drug target for preventing hypertension-induced vascular remodeling in a group of patients, in whom lowering the blood pressure to optimal range is harmful or causes intolerable side effects

Modulation of Mitochondrial Quality Control Processes by BGP- 15 in Oxidative Stress Scenarios: From Cell Culture to Heart Failure

Heart failure (HF) is a complex chronic clinical disease characterized by among others the damage of the mitochondrial network. The disruption of the mitochondrial quality control and the imbalance in fusion-fission processes lead to a lack of energy supply and, finally, to cell death. BGP-15 (O-[3-piperidino-2-hydroxy-1-propyl]-nicotinic acid amidoxime dihydrochloride) is an insulin sensitizer molecule and has a cytoprotective effect in a wide variety of experimental models. In our recent work, we aimed to clarify the mitochondrial protective effects of BGP-15 in a hypertension-induced heart failure model and “in vitro.” Spontaneously hypertensive rats (SHRs) received BGP-15 or placebo for 18 weeks. BGP-15 treatment preserved the normal mitochondrial ultrastructure and enhanced the mitochondrial fusion. Neonatal rat cardiomyocytes (NRCMs) were stressed by hydrogen-peroxide. BGP-15 treatment inhibited the mitochondrial fission processes, promoted mitochondrial fusion, maintained the integrity of the mitochondrial genome, and moreover enhanced the de novo biogenesis of the mitochondria. As a result of these effects, BGP-15 treatment also supports the maintenance of mitochondrial function through the preservation of the mitochondrial structure during hydrogen peroxide-induced oxidative stress as well as in an “in vivo” heart failure model. It offers the possibility, which pharmacological modulation of mitochondrial quality control under oxidative stress could be a novel therapeutic approach in heart failure

Protective effects of the novel amine-oxidase inhibitor multi-target drug SZV 1287 on streptozotocin-induced beta cell damage and diabetic complications in rats

Diabetes mellitus is a common metabolic disease leading to hyperglycemia due to insufficient pancreatic insulin production or effect. Amine oxidase copper containing 3 (AOC3) is an enzyme that belongs to the semicarbazide-sensitive amine oxidase family, which may be a novel therapeutic target to treat diabetic complications. We aimed to explore the effects of AOC3 inhibition and to test the actions of our novel AOC3 inhibitor multi-target drug candidate, SZV 1287, compared to a selective reference compound, LJP 1207, in an 8-week long insulin-controlled streptozotocin (STZ)-induced (60 mg/kg i.p.) rat diabetes model. Both AOC3 inhibitors (20 mg/kg, daily s.c. injections) were protective against STZ-induced pancreatic beta cell damage determined by insulin immunohistochemistry and radioimmunoassay, neuropathic cold hypersensitivity measured by paw withdrawal latency decrease from 0 °C water, and retinal dysfunction detected by electroretinography. SZV 1287 showed greater inhibitory effects on beta cell damage, and reduced retinal apoptosis shown by histochemistry. Mechanical hypersensitivity measured by aesthesiometry, cardiac dysfunction and nitrosative stress determined by echocardiography and immunohistochemistry/Western blot, respectively, serum Na+, K+, fructosamine, and urine microalbumin, creatinine, total protein/creatinine ratio alterations did not develop in response to diabetes. None of these parameters were influenced by the treatments except for SZV 1287 reducing serum fructosamine and LJP 1207 increasing urine creatinine. We provide the first evidence for protective effects of AOC3 inhibition on STZ-induced pancreatic beta cell damage, neuropathic cold hypersensitivity and diabetic retinal dysfunction. Long-term treatment with our novel multi-target analgesic candidate, SZV 1287, is safe and effective also under diabetic conditions

Diastolic dysfunction in prediabetic male rats: role of mitochondrial oxidative stress

Although incidence and prevalence of prediabetes are increasing, little is known on its cardiac effects. Therefore, our aim was to investigate the effect of prediabetes on cardiac function and to characterize parameters and pathways associated with deteriorated cardiac performance. Long-Evans rats were fed with either control or high-fat chow for 21 weeks and treated with a single low dose (20 mg/kg) streptozotocin at week 4. High-fat and streptozotocin treatment induced prediabetes as characterized by slightly elevated fasting blood glucose, impaired glucose- and insulin tolerance, increased visceral adipose tissue and plasma leptin levels, as well as sensory neuropathy. In prediabetic animals a mild diastolic dysfunction was observed, the number of myocardial lipid droplets increased, and left ventricular mass and wall thickness were elevated, however, no molecular sign of fibrosis or cardiac hypertrophy was evidenced. In prediabetes, production of reactive oxygen species was elevated in subsarcolemmal mitochondria. Expression of mitofusin-2 was increased while the phosphorylation of phospholamban and expression of Bcl-2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3, a marker of mitophagy) decreased. However, expression of other markers of cardiac auto- and mitophagy, mitochondrial dynamics, inflammation, heat shock proteins, Ca2+/calmodulin-dependent protein kinase II, mTOR or apoptotic pathways were unchanged in prediabetes. This is the first comprehensive analysis of cardiac effects of prediabetes indicating that mild diastolic dysfunction and cardiac hypertrophy are multifactorial phenomena which is associated with early changes in mitophagy, cardiac lipid accumulation and elevated oxidative stress, and that prediabetes-induced oxidative stress originates from the subsarcolemmal mitochondria