Mixture of Doxycycline, ML-7 and L-NAME Restores the Pro- and Antioxidant Balance during Myocardial Infarction-In Vivo Pig Model Study

The restoration of blood flow to the ischemic myocardium inflicts ischemia/reperfusion (I/R) heart injury (IRI). The main contributors to IRI are increased oxidative stress and subsequent excessive production of ROS, increased expression of NOS and peroxinitate, activation of MMPs, and enhanced posttranslational modifications of contractile proteins, which make them more susceptible to proteolytic degradation. Since the pathophysiology of IRI is a complex issue, and thus, various therapeutic strategies are required to prevent or reduce IRI and microvascular dysfunction, in the current study we proposed an innovative multi-drug therapy using low concentrations of drugs applied intracoronary to reach microvessels in order to stabilize the pro- and antioxidant balance during a MI in an in vivo pig model. The ability of a mixture of doxycycline (1 μM), ML-7 (0.5 μM), and L-NAME (2 μM) to modulate the pro- and antioxidative balance was tested in the left ventricle tissue and blood samples. Data showed that infusion of a MIX reduced the total oxidative status (TOS), oxidative stress index (OSI), and malondialdehyde (MDA). It also increased the total antioxidant capacity, confirming its antioxidative properties. MIX administration also reduced the activity of MMP-2 and MMP-9, and then decreased the release of MLC1 and BNP-26 into plasma. This study demonstrated that intracoronary administration of low concentrations of doxycycline in combination with ML-7 and L-NAME is incredibly efficient in regulating pro- and antioxidant balance during MI.

Klotho inhibits IGF1R/PI3K/AKT signalling pathway and protects the heart from oxidative stress during ischemia/reperfusion injury

Ischemia/reperfusion injury (IRI) of the heart involves the activation of oxidative and proapoptotic pathways. Simultaneously Klotho protein presents anti-aging, antiapoptotic and antioxidative properties. Therefore, this study aimed to evaluate the effect of Klotho protein on oxidative stress in hearts subjected to IRI. Isolated rat hearts perfused with the Langendorff method were subjected to ischemia, followed by reperfusion, in the presence or absence of recombinant rat Klotho protein. The factors involved in the activation of insulin-like growth factor receptor (IGF1R)/phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT) signalling pathway were evaluated. IRI caused activation of the IGF1R (p = 0.0122)/PI3K (p = 0.0022) signalling, as compared to the aerobic control group. Infusion supply of Klotho protein during IRI significantly reduced the level of phospho-IGF1R (p = 0.0436), PI3K (p = 0.0218) and phospho-AKT (p = 0.0020). Transcriptional activity of forkhead box protein O3 (FOXO3) was reduced (p = 0.0207) in hearts subjected to IRI, compared to aerobic control. Administration of Klotho decreased phosphorylation of FOXO3 (p = 0.0355), and enhanced activity of glutathione peroxidase (p = 0.0452) and superoxide dismutase (p = 0.0060) in IRI + Klotho group. The levels of reactive oxygen/nitrogen species (ROS/RNS) (p = 0.0480) and hydrogen peroxide (H2O2) (p = 0.0460), and heart injury (p = 0.0005) were significantly increased in hearts from the IRI group in comparison to the aerobic group. Klotho reduced NADPH oxidase 2 (NOX2) (p = 0.0390), ROS/RNS (p = 0.0435) and H2O2 (p = 0.0392) levels, and heart damage (p = 0.0286) in the hearts subjected to IRI. In conclusion, Klotho contributed to the protection of the heart against IRI and oxidative stress via inhibition of the IGF1R/PI3K/AKT pathway, thus can be recognized as a novel cardiopreventive/cardioprotective agent.

Mitoquinone Alleviates Donation after Cardiac Death Kidney Injury during Hypothermic Machine Perfusion in Rat Model

Transplanted organs are subjected to harmful conditions through stopping blood flow, hypothermic storage of the graft, and subsequent reperfusion. In particular, kidneys donated from patients after cardiac arrest (DCD) are classified as more vulnerable to ischemia-reperfusion injury (IRI). Hypothermic machine perfusion is proposed as a solution for better kidney storage before transplantation, and it is a good platform for additional graft treatment. Antioxidants have gained interest in regenerative medicine due to their ability to scavenge reactive oxygen species (ROS), which play a key role in IRI. We evaluated the effect of Mitoquinone (MitoQ), a strong mitochondria-targeted antioxidant, administered directly to the perfusing buffer. Rat kidneys were isolated, randomly classified into one of the following groups, donation after brainstem death (DBD), DCD, and DCD with MitoQ, and perfused for 22 hours with a hypothermic machine perfusion system. Subsequently, we detected levels of kidney injury (KIM-1) and oxidative stress (ROS/RNS, cytochrome C oxidase, and mitochondrial integrity) markers. We compared the activation of the apoptosis pathway (caspase 3 and 9), the concentration of phosphorylated Akt (pAkt), and the pAkt/total Akt ratio. MitoQ reduces KIM-1 concentration, total ROS/RNS, and the level of caspases. We observed a decrease in pAkt and the pAkt/total Akt ratio after drug administration. The length of warm ischemia time negatively impacts the graft condition. However, MitoQ added to the perfusing system as an 'on pump' therapy mitigates injury to the kidney before transplantation by inhibiting apoptosis and reducing ROS/RNS levels. We propose MitoQ as a potential drug for DCD graft preconditioning.

Poster No. 050 Klotho protein supports mechanical function and prevents MMP-mediated injury of heart during ischemia/reperfusion

Background

The injury of the myocardium during ischemia/reperfusion (IRI) involves metabolic, morphological, and contractile disorders. Klotho is a membrane or soluble anti-aging protein. Recent studies have proven the correlation between Klotho deficiency and the occurrence and development of cardiovascular diseases. The study aimed to evaluate the effect of Klotho protein on hearts subjected to IRI.

Material and methods

Isolated Wistar rat hearts perfused with the Langendorff method were subjected to ischemia, followed by reperfusion, in the presence or absence of Klotho protein. Hemodynamic parameters and the levels of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-Κb), nitrate/nitrite, inducible nitric oxide synthase (iNOS), asymmetric dimethylarginine (ADMA), matrix metalloproteinase 2 (MMP-2), MMP-9 and tissue inhibitor of MMP type 4 (TIMP-4) were evaluated.

Results

Infusion supply of Klotho during IRI resulted in the recovery of contractile function (P = 0.031) and heart rate (P = 0.02). IRI activated MMP-2 (P = 0.042) and MMP-9 (P = 0.041) in hearts, as compared to aerobic control. Klotho contributed to increase in iNOS level (P = 0.02), and decreased levels of NF-Κb (P = 0.006), ADMA (P = 0.007), nitrate/nitrite (P = 0.022), MMP-2 (P = 0.024) and MMP-9 (P < 0.001), as compared to IRI group.

Conclusions

Klotho protein preserved heart mechanical function and reduced the level of proteolytic enzymes in the heart. Thus, Klotho can be recognized as a novel cardiopreventive/cardioprotective agent in ischemic damage.

This work was supported by the National Science Centre, Poland [grant number 2019/33/N/NZ3/01649].

The Klotho protein supports redox balance and metabolic functions of cardiomyocytes during ischemia/reperfusion injury

Background

Acute heart ischemia followed by reperfusion leads to overproduction of reactive oxygen/nitrogen species (ROS/RNS), disrupted expression of nitric oxide synthase (NOS) and unbalanced glucose metabolism. Klotho is a membrane-bound or soluble protein that exerts protective activity in many organs. While Klotho is produced mainly in the kidneys and brain, it has been recently proven that Klotho is expressed in the cardiomyocytes as well. This study aimed to show the influence of the Klotho protein on oxidative/nitrosative stress and metabolic function of the cardiomyocytes subjected to ischemia/reperfusion (I/R) injury.

Methods

Human cardiac myocytes underwent in vitro chemical I/R (with sodium cyanide and 2-deoxyglucose), in the presence or absence of the recombinant human Klotho protein. The present study included an investigation of cell injury markers, level of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX), level of oxidative/nitrosative stress and metabolic processes of the cardiomyocytes.

Results

Administration of Klotho protein resulted in mitigation of injury, decreased level of NOX2 and NOX4, reduced generation of ROS/RNS and hydrogen peroxide (H₂O₂), decreased expression of inducible NOS and limited production of nitrates/nitrites in cells under I/R. Glucose uptake and lactate production in the cardiomyocytes subjected to I/R were normalized after Klotho supplementation.

Conclusions

The Klotho protein participates in the regulation of redox balance and supports metabolic homeostasis of the cardiomyocytes and hence, contributes to protection against I/R injury.

Expression of atrial‑fetal light chains in cultured human cardiomyocytes after chemical ischemia‑reperfusion injury

Atrial light chains (ALC1) are naturally present in adult heart atria, while ventricular light chains (VLC1) are predominant in ventricles. Degradation of VLC1 and re-expression of ALC1 in heart ventricles are associated with heart disorders in response to pressure overload. The aim of the current study was to investigate changes in myosin light chain expression after simulated ischemia and simulated reperfusion (sI/sR). Human cardiomyocytes (HCM) isolated from adult heart ventricles were subjected to chemical ischemia. The control group was maintained under aerobic conditions. Myocyte injury was determined by testing lactate dehydrogenase (LDH) activity. The gene expression of ALC1, VLC1 and MMP-2 were assessed by reverse transcription-quatitive PCR. Additionally, protein synthesis was measured using ELISA kits and MMP-2 activity was measured by zymography. The results revealed that LDH activity was increased in sI/sR cell-conditioned medium (P=0.02), confirming the ischemic damage of HCM. ALC1 gene expression and content in HCM were also increased in the sI/sR group (P=0.03 and P<0.001, respectively), while VLC1 gene expression after sI/sR was decreased (P=0.008). Furthermore, MMP-2 gene expression and synthesis were lower in the sI/sR group when compared with the aerobic control group (P<0.001 and P=0.03, respectively). MMP-2 activity was also increased in sI/sR cell-conditioned medium (P=0.006). In conclusion, sI/sR treatment led to increased ALC1 and decreased VLC1 expression in ventricular cardiomyocytes, which may constitute an adaptive mechanism to altered conditions and contribute to the improvement of heart function.

Ameliorating Effect of Klotho Protein on Rat Heart during I/R Injury

An essential procedure for the treatment of myocardial infarction is restoration of blood flow in the obstructed infarct artery, which may cause ischaemia/reperfusion (I/R) injury. Heart I/R injury manifests in oxidative stress, metabolic and morphological disorders, or cardiac contractile dysfunction. Klotho protein was found to be produced in the heart tissue and participate in antioxidation or ion homeostasis. The aim of this study was to examine an influence of Klotho protein on the heart subjected to I/R injury. Wistar rats served as a surrogate heart model ex vivo. Rat hearts perfused using the Langendorff method were subjected to global no-flow ischaemia, and isolated rat cardiomyocytes underwent chemical I/R in vitro, with or without recombinant Klotho protein administration. Haemodynamic parameters of heart function, cell contractility, markers of I/R injury and oxidative stress, and the level of contractile proteins such as myosin light chain 1 (MLC1) and troponin I (TnI) were measured. The treatment of hearts subjected to I/R injury with Klotho protein resulted in a recovery of heart mechanical function and ameliorated myocyte contractility. This improvement was associated with decreased tissue injury, enhanced antioxidant capacity, and reduced release of MLC1 and TnI. The present research showed the contribution of Klotho to cardioprevention during I/R. Thus, Klotho protein may support the protection from I/R injury and prevention of contractile dysfunction in the rat heart.

A drug cocktail for protecting against ischemia-reperfusion injury

Ischemia followed by reperfusion (I/R) of cardiomyocytes causes release of a large amount of inducible nitric oxide (NO) synthase (iNOS) followed by an increase of asymmetric dimethylarginine (ADMA). ADMA disrupts NO signaling by switching of the NOS activity from NO to the production of reactive oxygen species (ROS). Previously, we have shown that pretreatment of the hearts by co-administration of sub-threshold concentrations of doxycycline, a matrix metalloproteinase (MMPs) inhibitor, ML-7 an inhibitor of myosin light-chain kinase (MLCK) and L-NAME a non-selective NOS inhibitor protects the heart against I/R injury. In this study, we replaced the L-NAME with 1400W (selective inhibitor of iNOS) in the drug cocktail that was Langendorff-perfused into the hearts of Wistar rats before (prevention) or after (treatment) the induction of I/R. This pre-treatment resulted in full protection of contractility, decreased production of iNOS and ADMA and normalized the bioavailability of NO in the I/R hearts. Thus, the formulated drug cocktail protects the heart from I/R injury.

Cardioprotective effect of MMP-2-inhibitor-NO-donor hybrid against ischaemia/reperfusion injury

Hypoxic injury of cardiovascular system is one of the most frequent complications following ischaemia. Heart injury arises from increased degradation of contractile proteins, such as myosin light chains (MLCs) and troponin I by matrix metalloproteinase 2 (MMP‐2). The aim of the current research was to study the effects of 5‐phenyloxyphenyl‐5‐aminoalkyl nitrate barbiturate (MMP‐2‐inhibitor‐NO‐donor hybrid) on hearts subjected to ischaemia/reperfusion (I/R) injury. Primary human cardiac myocytes and Wistar rat hearts perfused using Langendorff method have been used. Human cardiomyocytes or rat hearts were subjected to I/R in the presence or absence of tested hybrid. Haemodynamic parameters of heart function, markers of I/R injury, gene and protein expression of MMP‐2, MMP‐9, inducible form of NOS (iNOS), asymmetric dimethylarginine (ADMA), as well as MMP‐2 activity were measured. Mechanical heart function, coronary flow (CF) and heart rate (HR) were decreased in hearts subjected to I/R Treatment of hearts with the hybrid (1‐10 µmol/L) resulted in a concentration‐dependent recovery of mechanical function, improved CF and HR. This improvement was associated with decreased tissue injury and reduction of synthesis and activity of MMP‐2. Decreased activity of intracellular MMP‐2 led to reduced degradation of MLC and improved myocyte contractility in a concentration‐dependent manner. An infusion of a MMP‐2‐inhibitor‐NO‐donor hybrid into I/R hearts decreased the expression of iNOS and reduced the levels of ADMA. Thus, 5‐phenyloxyphenyl‐5‐aminoalkyl nitrate barbiturate protects heart from I/R injury.

The Biological Role of Klotho Protein in the Development of Cardiovascular Diseases

Klotho is a membrane-bound or soluble antiaging protein, whose protective activity is essential for a proper function of many organs. In 1997, an accidental insertion of a transgene led to creation of transgenic mice with several age-related disorders. In Klotho-deficient mice, the inherited phenotypes closely resemble human aging, while in an animal model of Klotho overexpression, the lifespan is extended. Klotho protein is detected mainly in the kidneys and brain. It is a coreceptor for fibroblast growth factor and hence is involved in maintaining endocrine system homeostasis. Furthermore, an inhibition of insulin/insulin-like growth factor-1 signaling pathway by Klotho regulates oxidative stress and reduces cell death. The association between serum Klotho and the classic risk factors, as well as the clinical history of cardiovascular disease, was also shown. There are a lot of evidences that Klotho deficiency correlates with the occurrence and development of coronary artery disease, atherosclerosis, myocardial infarction, and left ventricular hypertrophy. Therefore, an involvement of Klotho in the signaling pathways and in regulation of a proper cell metabolism could be a crucial factor in the cardiac and vascular protection. It is also well established that Klotho protein enhances the antioxidative response via augmented production of superoxide dismutase and reduced generation of reactive oxygen species. Recent studies have proven an expression of Klotho in cardiomyocytes and its increased expression in stress-related heart injury. Thus, the antioxidative and antiapoptotic activity of Klotho could be considered as the novel protective factor in cardiovascular disease and heart injury.

Low frequency electromagnetic field decreases ischemia-reperfusion injury of human cardiomyocytes and supports their metabolic function

Electromagnetic field at extremely low frequencies plays a significant role in the physiological function of human tissues and systems. It is shown that electromagnetic field inhibits production of reactive oxygen species which are involved in heart injury triggered by oxidative stress. We hypothesize that low frequency electromagnetic field protects function of cardiac cells from ischemia-reperfusion injury. Human cardiac myocytes, endothelial cells, and cardiac fibroblast underwent ischemia-reperfusion conditions in the presence or in the absence of low frequency electromagnetic field. LDH and MMP-2 activities (as markers of cell injury), and cell metabolic activity (by fluorescein diacetate staining) were measured to determine the protective role of low frequency electromagnetic field. Our data showed that short courses of low frequency electromagnetic field protect cardiac cells from cellular damage and preserve their metabolic activity during ischemia-reperfusion. This study demonstrates the possibility to use of low frequency electromagnetic field as strategy for the prevention or therapy of ischemia-reperfusion injury. Impact statement In our study, we showed that LF-EMF may be protective for heart during ischemia-reperfusion (I/R). Following is the short description of the main findings: (a) the response to the I/R injury was different for endothelial cells, fibroblasts, and cardiomyocytes; (b) I/R decreases MMP-2 activity in cardiac myocytes and fibroblasts;

L-NAME improves doxycycline and ML-7 cardioprotection from oxidative stress

Matrix metalloproteinase-2 (MMP-2) mediated degradation of myosin light chain 1 (MLC1) and troponin I (TnI) contributes to myocardial ischemia/reperfusion (I/R) injury. Modifications of MLC1 triggered by oxidative stress are mediated by myosin light chain kinase (MLCK), nitric oxide synthase (NOS), and MMP-2. Previous studies have shown that inhibiting both MLCK and MMP-2 protects against I/R injury. Here, we hypothesized that the addition of NOS inhibitor (L-NAME) at subprotective concentration to the mixture of subprotective concentrations of ML-7 and doxycycline (Doxy), will increase a synergistic cardioprotection of Doxy and ML-7 during I/R. Isolated rat hearts were subjected to global ischemia without or with administration of the mixture of inhibitors. Markers of I/R injury were measured in hearts and coronary effluents. Addition of L-NAME to the mixture of Doxy and ML-7 led to full recovery of heart contractility in comparison to combination of Doxy and ML-7. Improved heart contractility was associated with reduced degradation of TnI and MLC1. The combined administration of NOS, MMP-2 and MLCK inhibitors provides a novel strategy to protect heart from I/R injury.

Multidrug prevention or therapy of ischemia-reperfusion injury of the heart-Mini-review

Restoration of blood flow to myocardium previously subjected to ischemia leads to ischemia/reperfusion injury due to oxidative stress. An increased production of toxic peroxynitrite, an enhanced phosphorylation and nitration/nitrosylation of myocyte contractile proteins and overactivation of matrix metalloproteinases -are only one of the several causes of heart damage. Multifactorial basis of ischemia/reperfusion injury demands the use of multiple pharmacological agents, inhibiting several pathways of cardiac injury. Nevertheless, the use of these drugs in their therapeutic doses, apart from their role in the treatment of pathological events, may also disturb physiological processes leading to numerous side-effects. Therefore current preclinical studies focuses on multidrug therapies in their low concentration. Synergistic or additive effect of low multidrug therapy inhibit pathological processes while maintaining the proper cell function and avoid alteration of physiological role of important functional proteins. This study provides information about multidrug strategies for the prevention/treatment of cardiac injury induced by oxidative stress.

Diagnostic usefulness of sCD163, procalcitonin and neopterin for sepsis risk assessment in critically ill patients

BACKGROUND

Sepsis is one of the most common causes of hospitalization and it is characterized by a high mortality rate in spite of the great progress in diagnosis and treatment achieved in recent years. Early diagnosis of sepsis is one of the most important elements of effective treatment. The clinical symptoms are not specific and biomarkers are considered to be useful tools in sepsis diagnostics.

OBJECTIVES

The aim of our study was to evaluate the diagnostic value of sCD163 as a marker of sepsis and a comparison of it with procalcitonin and neopterin in ICU patients.

MATERIAL AND METHODS

Concentrations of PCT, sCD163 and NPT were measured in 52 serum samples collected from 30 patients of the Department of Anesthesiology and Intensive Therapy of the University Hospital in Wroclaw. Venous blood was collected on the 1st and 3rd day of hospitalization. The Human CD163 Quantikine ELISA Kit was used to determine the concentrations of sCD163. Neopterin concentrations were measured by a Neopterin ELISA kit. PCT was measured at the University Center of Laboratory Diagnostics in Wroclaw using an automatic VIDAS® B.R.A.H.M.S. PCT assay.

RESULTS

Our study showed that there was a significant difference between the values obtained in the study and the reference group for PCT (p < 0.0001), sCD163 (p = 0.0001) and NPT (p = 0.0001), whereas there was no difference observed between the samples obtained on the 1st and 3rd day (p = 0.5129). The area under the ROC curve was 0.847, and was comparable to the AUC of procalcitonin (0.840), and slightly higher than the AUC of neopterin (0.763), although these differences were not significant (p = 0.2990 and p = 0.9329, respectively).

CONCLUSIONS

sCD163 and neopterin are promising parameters in the diagnosis of sepsis, and their value in the diagnosis of sepsis in critically ill patients may be comparable to procalcitonin.

An infection of human adenovirus 31 affects the differentiation of preadipocytes into fat cells, its metabolic profile and fat accumulation

The primary issue undertaken in this study was to test the hypothesis that preadipocytes would have intrinsically elevated propensity to differentiate into mature adipocytes due to HAdV31 infection. To prove that, the metabolic and molecular mechanisms responsible for HAdV31-induced adipogenesis were examined. 3T3L1 cells (mouse embryonic fibroblast, adipose like cell line) were used as a surrogate model to analyze an increased proliferation, differentiation, and maturation of preadipocytes infected with human adenovirus. An expression of E4orf1, C/EBP-β, PPAR-γ, GAPDH, aP2, LEP, and fatty acid synthase genes, intracellular lipid accumulation as well as cytokine release from the fat cells were assessed. Data showed that HAdV31 increased an expression of C/EBP-β and PPAR-γ genes leading to an enhanced differentiation of preadipocytes into fat cells. Besides, overexpression of GAPDH and fatty acid synthase, and decreased expression of leptin caused an increased accumulation of intracellular lipids. Secretion of TNF-α and IL-6 from HAdV31-infected cells was strongly decreased, leading to unlimited virus replication. The results obtained from this study provided the evidences that HAdV31, likewise previously documented HAdV36, is a subsequent human adenovirus affecting the differentiation and lipid accumulation of 3T3L1 cells.

Is there any link between visceral obesity and adenovirus infections in the Polish population?

BACKGROUND

Obesity is a chronic disease of multiple etiologies. Alongside the traditionally recognized causes of obesity, such as genetic inheritance and behaviour/environmental factors, in recent years adenoviral infections have been considered as a possible cause of obesity. Although numerous studies involving animals confirmed a strong relation between adenoviral infection and increased predisposition to obesity, an association of AdVs with human obesity has not been established conclusively.

OBJECTIVES

The main aim of this study was to establish an association between seroprevalence of adenoviruses and obesity in the Polish population.

MATERIAL AND METHODS

Eighty-six subjects (both obese and non-obese) participated in this study. The presence and the concentration of typically non-specific antibodies to human adenoviruses in serum were determined using ELISA immunoassay. A serum lipid-profile was evaluated using commercial tests.

RESULTS

A total of 89.5% of subjects were positive for AdV-IgG (n = 77); 10.5% (n = 9) were negative. In non-obese or lean AdV-IgG positive subjects, the parameters as: body weight (63.5 vs. 57.0, p = 0.02), WHR (0.77 vs. 0.73, p = 0.02) and waist circumference (74.5 vs. 69.0, p = 0.01) were significantly higher as AdV-IgG negative individuals.

CONCLUSIONS

We showed that there is an association between the presence of type unspecific anti-AdV antibodies in the serum and elevated body weight, BMI, WHR and waist circumference in lean and non-obese subjects from the Polish population.