Oxidative stress, DNA damage and repair in heart failure patients after implantation of continuous flow left ventricular assist devices

Neutrophil Structural and Functional Alterations After High Mechanical Shear Stress Exposure

Patients on mechanical circulatory support are prone to infections, increasing morbidity and mortality. These circulatory support devices generate high mechanical shear stress (HMSS) that can causes trauma to blood. When leukocytes become damaged, their immune response function may be impaired or weakened, leading to increased infection vulnerability. This study examined neutrophil structural and functional alterations after exposure to 75, 125, and 175 Pa HMSS for 1 second. Human blood was exposed to three levels of HMSS using a blood shearing device. Neutrophil morphological alteration was characterized by examining blood smears. Flow cytometry assays were used to analyze expression levels of CD62L and CD162 receptors, activation level (CD11b), and aggregation (platelet-neutrophil aggregates). Neutrophil phagocytosis and rolling were examined via functional assays. The results show neutrophil structure (morphology and surface receptors) and function (activation, aggregation, phagocytosis, rolling) were significantly altered after HMSS exposure. These alterations include cell membrane damage, loss of surface receptors (CD62L and CD162), initiation of activation and aggregation, upregulation of phagocytic ability and increased rolling speed. The alterations were the most severe after 175 Pa exposure. HMSS caused damage and activation of neutrophils, potentially impairing normal neutrophil function, leading to weakened immune defense and increasing a patient's vulnerability to infections.

Genome instability in peripheral blood lymphocytes of patients with heart failure and reduced ejection fraction

Heart failure (HF) is a complex clinical condition characterized by functional and structural defects of the myocardium, but genetic and environmental factors are considered to play an important role in the development of the disease. In the present study, we investigated the genome instability (DNA and chromosomal damage) in patients with heart failure with reduced ejection fraction (HFrEF) ≤40% and its association with risk factors. The studied population included 48 individuals, of which 29 HFrEF patients (mean age 57.41 ± 5.74 years) and 19 healthy controls (mean age 57.63 ± 6.09 years). The genetic damage index in peripheral blood lymphocytes was analyzed using the comet assay, while micronuclei frequency and nuclear division index were analyzed using the cytokinesis-block micronucleus assay. Our results showed that HFrEF patients had a significantly higher genetic damage index compared with the healthy controls (P < .001). Cytokinesis-block micronucleus assay showed that the average micronucleus frequency in peripheral blood lymphocytes of patients was significantly higher, while the nuclear division index values were significantly lower than in controls (P < .01). Using multiple linear regression analysis, pathological state, ejection fraction, creatinine, glucose, associated disease, residence, proBNP, troponin, urea, ACE-inhibitors, and length of the drug therapy were identified as predictors of DNA and/or chromosomal damage in HF patients. We can conclude that DNA and chromosomal damage was increased in patients with HF, which may be a consequence of disease and/or drug therapy.

Neutrophil dysfunction due to continuous mechanical shear exposure in mechanically assisted circulation in vitro

OBJECTIVE

Leukocytes play an important role in the body's immune system. The aim of this study was to assess alterations in neutrophil phenotype and function in pump-assisted circulation in vitro.

METHODS

Human blood was circulated for four hours in three circulatory flow loops with a CentriMag blood pump operated at a flow of 4.5 L/min at three rotational speeds (2100, 2800, and 4000 rpm), against three pressure heads (75, 150, and 350 mm Hg), respectively. Blood samples were collected hourly for analyses of neutrophil activation state (Mac-1, CD62L, CD162), neutrophil reactive oxygen species (ROS) production, apoptosis, and neutrophil phagocytosis.

RESULTS

Activated neutrophils indicated by both Mac-1 expression and decreased surface expression of CD62L and CD162 receptors increased with time in three loops. The highest level of neutrophil activation was observed in the loop with the highest rotational speed. Platelet-neutrophil aggregates (PNAs) progressively increased in two loops with lower rotational speeds. PNAs peaked at one hour after circulation and decreased subsequently in the loop with the highest rotational speed. Neutrophil ROS production dramatically increased at one hour after circulation and decreased subsequently in all three loops with similar levels and trends. Apoptotic neutrophils increased with time in all three loops. Neutrophil phagocytosis capacity in three loops initially elevated at one hour after circulation and decreased subsequently. Apoptosis and altered phagocytosis were dependent on rotational speed.

CONCLUSIONS

Our study revealed that the pump-assisted circulation induced neutrophil activation, apoptosis, and functional impairment. The alterations were strongly associated with pump operating condition and duration.

Multidisciplinary management of pleural infection after ventricular assist device implantation

Background

Postsurgical pleural infection is a life-threatening complication after implantation of artificial devices such as ventricular assist devices (VADs). The treatment can be challenging and the evidence in the literature is very limited. Here we report our multidisciplinary approach of the management of pleural infection after VAD implantation.

Methods

Between March 2014 and December 2019, 33 patients developed postoperative pleural infection after VAD implantation and underwent thoracic surgical intervention at our institution. All patients were prospectively enrolled in this analysis. Data were retrospectively analyzed. Primary outcome was the 90-day mortality rate. Length of ICU stay related to pleural infection, chest tube duration, re-thoracotomy rate and length of ventilatory support represented secondary outcomes.

Results

The 90-day mortality rate was 6% (2 patients). The mean ICU stay related to the pleural infection was 6 days (2-24 days). Video-assisted thoracoscopic surgery (VATS) was performed in all patients. Conversion to thoracotomy was necessary in 12 cases. Decortication and parietal pleurectomy in addition to hematoma and empyema removal was performed in all patients. Due to diffuse bleeding, packing of the thoracic cavity with temporary thoracic closure was necessary in 10 patients. Depacking was performed after a mean of 3 days (3-7 days). Recurrent empyema or bleeding after definitive chest closure was not observed. Lung resection was performed in 3 patients.

Conclusions

Thoracic surgical management of pleural infection in patients after VAD implantation is challenging and complicated due to the inevitable anticoagulative therapy. A perioperative multidisciplinary management which includes the early involvement of thoracic surgical expertise helps to improve survival in this very complex patient cohort.

Neutrophil injury and function alterations induced by high mechanical shear stress with short exposure time

High mechanical shear stresses (HMSS) can cause damage to blood, which manifests as morphologic changes, shortened life span, biochemical alterations, and complete rupture of blood cells and proteins, leading to the alterations of normal blood function. The aim of this study is to determine the state of neutrophil activation and function alterations caused by HMSS with short exposure time relevant to ventricular assist devices. Blood from healthy donors was exposed to three levels of HMSS (75Pa, 125Pa, and 175Pa) for a short exposure time (0.5 s) using our Couette-type blood-shearing device. Neutrophil activation (Mac-1, platelet-neutrophil aggregates) and surface expression levels of two key functional receptors (CD62L and CD162) on neutrophils were evaluated by flow cytometry. Neutrophil phagocytosis and transmigration were also examined with functional assays. Results showed that the expression of Mac-1 on neutrophils and platelet-neutrophil aggregates increased significantly while the level of CD62L expression on neutrophils decreased significantly after the exposure to HMSS. The Mac-1 expression progressively increased while the CD62L expression progressively decreased with the increased level of HMSS. The level of CD162 expression on neutrophils slightly increased after the exposure to HMSS, but the increase was not significant. The phagocytosis assay data revealed that the ability of neutrophils to phagocytose latex beads coated with fluorescently labeled rabbit IgG increased significantly with the increased level of HMSS. The transmigration ability of neutrophils slightly increased after the exposure to HMSS, but did not reach a significant level. In summary, HMSS with a short exposure time of 0.5 seconds could induce neutrophil activation, platelet-neutrophil aggregation, shedding of CD62L receptor, and increased phagocytic ability. However, the exposure to the three levels of HMSS did not cause a significant change in neutrophil transmigration capacity and shedding of CD162 receptor on neutrophils.

Unlocking the Value of White Blood Cells for Heart Failure Diagnosis

Cardiovascular disease (CVD) is the single greatest cause of mortality and morbidity worldwide. Inciting 85% of CVD fatalities is heart failure, often resulting in or from a myocardial infarction. Early detection along with pharmacological treatment and lifestyle adaptation can result in better prognosis. Biomarkers are molecular or physiological measures that indicate disease presence, status, and severity. However, not all forms of heart failure are created equal. Current mainstay biomarkers for heart failure, including NT-pro-BNP and ejection fraction, lack sensitivity for many patients. Circulating white blood cells and peripheral blood mononuclear cells (PBMCs) are emerging as surrogate biopsies, reflecting molecular changes in the heart. We discuss the advantages of PBMCs over other sources, as well as limitations and considerations. We urge medical center biobanks to collect, isolate and store circulating white blood cells as a rich source of biomarkers to catalyze the discovery of novel diagnostic tools for heart failure.

The Role of Nonglycolytic Glucose Metabolism in Myocardial Recovery Upon Mechanical Unloading and Circulatory Support in Chronic Heart Failure

BACKGROUND

Significant improvements in myocardial structure and function have been reported in some patients with advanced heart failure (termed responders [R]) following left ventricular assist device (LVAD)-induced mechanical unloading. This therapeutic strategy may alter myocardial energy metabolism in a manner that reverses the deleterious metabolic adaptations of the failing heart. Specifically, our previous work demonstrated a post-LVAD dissociation of glycolysis and oxidative-phosphorylation characterized by induction of glycolysis without subsequent increase in pyruvate oxidation through the tricarboxylic acid cycle. The underlying mechanisms responsible for this dissociation are not well understood. We hypothesized that the accumulated glycolytic intermediates are channeled into cardioprotective and repair pathways, such as the pentose-phosphate pathway and 1-carbon metabolism, which may mediate myocardial recovery in R.

METHODS

We prospectively obtained paired left ventricular apical myocardial tissue from nonfailing donor hearts as well as R and nonresponders at LVAD implantation (pre-LVAD) and transplantation (post-LVAD). We conducted protein expression and metabolite profiling and evaluated mitochondrial structure using electron microscopy.

RESULTS

Western blot analysis shows significant increase in rate-limiting enzymes of pentose-phosphate pathway and 1-carbon metabolism in post-LVAD R (post-R) as compared with post-LVAD nonresponders (post-NR). The metabolite levels of these enzyme substrates, such as sedoheptulose-6-phosphate (pentose phosphate pathway) and serine and glycine (1-carbon metabolism) were also decreased in Post-R. Furthermore, post-R had significantly higher reduced nicotinamide adenine dinucleotide phosphate levels, reduced reactive oxygen species levels, improved mitochondrial density, and enhanced glycosylation of the extracellular matrix protein, α-dystroglycan, all consistent with enhanced pentose-phosphate pathway and 1-carbon metabolism that correlated with the observed myocardial recovery.

CONCLUSIONS

The recovering heart appears to direct glycolytic metabolites into pentose-phosphate pathway and 1-carbon metabolism, which could contribute to cardioprotection by generating reduced nicotinamide adenine dinucleotide phosphate to enhance biosynthesis and by reducing oxidative stress. These findings provide further insights into mechanisms responsible for the beneficial effect of glycolysis induction during the recovery of failing human hearts after mechanical unloading.

Peripheral Blood Mononuclear Cells and Platelets Mitochondrial Dysfunction, Oxidative Stress, and Circulating mtDNA in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are devastating disorders and the leading cause of mortality worldwide. The pathophysiology of cardiovascular diseases is complex and multifactorial and, in the past years, mitochondrial dysfunction and excessive production of reactive oxygen species (ROS) have gained growing attention. Indeed, CVDs can be considered as a systemic alteration, and understanding the eventual implication of circulating blood cells peripheral blood mononuclear cells (PBMCs) and or platelets, and particularly their mitochondrial function, ROS production, and mitochondrial DNA (mtDNA) releases in patients with cardiac impairments, appears worthwhile. Interestingly, reports consistently demonstrate a reduced mitochondrial respiratory chain oxidative capacity related to the degree of CVD severity and to an increased ROS production by PBMCs. Further, circulating mtDNA level was generally modified in such patients. These data are critical steps in term of cardiac disease comprehension and further studies are warranted to challenge the possible adjunct of PBMCs’ and platelets’ mitochondrial dysfunction, oxidative stress, and circulating mtDNA as biomarkers of CVD diagnosis and prognosis. This new approach might also allow further interesting therapeutic developments.

Circulating Leukocytes and Oxidative Stress in Cardiovascular Diseases: A State of the Art

Increased oxidative stress from both mitochondrial and cytosolic sources contributes to the development and the progression of cardiovascular diseases (CVDs), and it is a target of therapeutic interventions. The numerous efforts made over the last decades in order to develop tools able to monitor the oxidative stress level in patients affected by CVDs rely on the need to gain information on the disease state. However, this goal has not been satisfactorily accomplished until now. Among others, the isolation of circulating leukocytes to measure their oxidant level offers a valid, noninvasive challenge that has been tested in few pathological contexts, including hypertension, atherosclerosis and its clinical manifestations, and heart failure. Since leukocytes circulate in the blood stream, it is expected that they might reflect quite closely both systemic and cardiovascular oxidative stress and provide useful information on the pathological condition. The results of the studies discussed in the present review article are promising. They highlight the importance of measuring oxidative stress level in circulating mononuclear cells in different CVDs with a consistent correlation between degree of oxidative stress and severity of CVD and of its complications. Importantly, they also point to a double role of leukocytes, both as a marker of disease condition and as a direct contributor to disease progression. Finally, they show that the oxidative stress level of leukocytes reflects the impact of therapeutic interventions. It is likely that the isolation of leukocytes and the measurement of oxidative stress, once adequately developed, may represent an eligible tool for both research and clinical purposes to monitor the role of oxidative stress on the promotion and progression of CVDs, as well as the impact of therapies.

Association of Oxidative Stress and Platelet Receptor Glycoprotein GPIbα and GPVI Shedding During Nonsurgical Bleeding in Heart Failure Patients With Continuous-Flow Left Ventricular Assist Device Support

Nonsurgical bleeding (NSB) in heart failure (HF) patients with continuous-flow left ventricular assist device (CF-LVAD) support is the most common clinical complication. The aim of this study was to investigate the association between oxidative stress and platelet glycoproteins GPIbα and GPVI shedding on the incidence of NSB in CF-LVAD patients. Fifty-one HF patients undergoing CF-LVAD implantation and 11 healthy volunteers were recruited. Fourteen patients developed NSB (bleeder group) during 1 month follow-up duration, while others were considered nonbleeder group (n = 37). Several biomarkers of oxidative stress were quantified at baseline and weekly intervals in all patients. Surface expression and plasma elements of platelet receptor glycoproteins GPIbα and GPVI were measured. Oxidative stress biomarkers and platelet GPIbα and GPVI receptor-shedding (decreased surface expression and higher plasma levels) were found to be preexisting conditions in baseline samples of both groups of HF patients when compared with healthy volunteers. Significantly elevated oxidative stress biomarkers and platelet glycoprotein receptor shedding were observed in postimplant bleeder group temporarily when compared with nonbleeder group. Strong significant associations between biomarkers of oxidative stress and platelet glycoprotein receptor shedding were observed, suggesting a possible role of oxidative stress in platelet integrin shedding leading to NSB in CF-LVAD patients. Receiver operating characteristic analyses of GPIbα and GPVI indicated that the likelihood of NSB had a predictive power of bleeding complication in CF-LVAD patients. In conclusion, elevated oxidative stress may play a role in GPIbα and GPVI shedding in the event of NSB. Thus, oxidative stress and GPIbα and GPVI shedding may be used as potential biomarkers for bleeding risk stratification in those patients.

Melatonin and its metabolites as chemical agents capable of directly repairing oxidized DNA

Oxidative stress mediates chemical damage to DNA yielding a wide variety of products. In this work, the potential capability of melatonin and several of its metabolites to repair directly (chemically) oxidative lesions in DNA was explored. It was found that all the investigated molecules are capable of repairing guanine-centered radical cations by electron transfer at very high rates, that is, diffusion-limited. They are also capable of repairing C-centered radicals in the sugar moiety of 2'-deoxyguanosine (2dG) by hydrogen atom transfer. Although this was identified as a rather slow process, with rate constants ranging from 1.75 to 5.32 × 10²  M^-1 s^-1 , it is expected to be fast enough to prevent propagation of the DNA damage. Melatonin metabolites 6-hydroxymelatonin (6OHM) and 4-hydroxymelatonin (4OHM) are also predicted to repair OH adducts in the imidazole ring. In particular, the rate constants corresponding to the repair of 8-OH-G adducts were found to be in the order of 10⁴  M^-1 s^-1 and are assisted by a water molecule. The results presented here strongly suggest that the role of melatonin in preventing DNA damage might be mediated by its capability, combined with that of its metabolites, to directly repair oxidized sites in DNA through different chemical routes.

Mechanical shear stress and leukocyte phenotype and function: Implications for ventricular assist device development and use

Heart failure remains a disease of ever increasing prevalence in the modern world. Patients with end-stage heart failure are being referred increasingly for mechanical circulatory support. Mechanical circulatory support can assist patients who are ineligible for transplant and stabilise eligible patients prior to transplantation. It is also used during cardiopulmonary bypass surgery to maintain circulation while operating on the heart. While mechanical circulatory support can stabilise heart failure and improve quality of life, complications such as infection and thrombosis remain a common risk. Leukocytes can contribute to both of these complications. Contact with foreign surfaces and the introduction of artificial mechanical shear stress can lead to the activation of leukocytes, reduced functionality and the release of pro-inflammatory and pro-thrombogenic microparticles. Assessing the impact of mechanical trauma to leukocytes is largely overlooked in comparison to red blood cells and platelets. This review provides an overview of the available literature on the effects of mechanical circulatory support systems on leukocyte phenotype and function. One purpose of this review is to emphasise the importance of studying mechanical trauma to leukocytes to better understand the occurrence of adverse events during mechanical circulatory support.

Folic acid modulates VPO1 DNA methylation levels and alleviates oxidative stress-induced apoptosis in vivo and in vitro

Endothelial cell injury and apoptosis play a primary role in the pathogenesis of atherosclerosis. Moreover, accumulating evidence indicates that oxidative injury is an important risk factor for endothelial cell damage. In addition, low folate levels are considered a contributing factor to promotion of vascular disease because of the deregulation of DNA methylation. We aimed to investigate the effects of folic acid on injuries induced by oxidative stress that occur via an epigenetic gene silencing mechanism in ApoE knockout mice fed a high-fat diet and in human umbilical vein endothelial cells treated with oxidized low-density lipoprotein (ox-LDL). We assessed how folic acid influenced the levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG, an oxidative DNA damage marker) and cellular apoptosis in in vivo and in vitro models. Furthermore, we analyzed DNA methyltransferase (DNMT) activity, vascular peroxidase 1 (VPO1) expression, and promoter methylation in human umbilical vein endothelial cells. Our data showed that folic acid reduced 8-OHdG levels and decreased apoptosis in the aortic tissue of ApoE^−/− mice. Likewise, our in vitro experiments showed that folic acid protects against endothelial dysfunction induced by ox-LDL by reducing reactive oxygen species (ROS)-derived oxidative injuries, 8-OHdG content, and the apoptosis ratio. Importantly, this effect was indirectly caused by increased DNMT activity and altered DNA methylation at VPO1 promoters, as well as changes in the abundance of VPO1 expression. Collectively, we conclude that folic acid supplementation may prevent oxidative stress-induced apoptosis and suppresses ROS levels through downregulating VPO1 as a consequence of changes in DNA methylation, which may contribute to beneficial effects on endothelial function.

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Folic acid reduces oxidative stress-induced injuries in atherosclerosis.

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Folic acid decreases 8-OHdG levels and apoptosis in vivo and in vitro.

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Folic acid supplementation increases DNMT levels and regulates VPO1 expression.

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VPO1 expression is modulated by epigenetic silencing via promoter methylation.

Assessment of trazodone-induced cardiotoxicity after repeated doses in rats

Trazodone (TRZ) is an antidepressant drug commonly used in the treatment of depression, anxiety, and insomnia. Although some studies demonstrated the adverse effects of TRZ related to cardiovascular system, the conflicting results were observed in these studies. Therefore, we aimed to investigate the cardiac adverse effects of TRZ in rats at repeated doses in our study. In accordance with this purpose, TRZ was administered orally to rats at 5, 10, and 20 mg/kg doses for 28 days. Electrocardiogram records, serum aspartate aminotransferase (AST), lactate dehydrogenase, creatine kinase-myoglobin band, cardiac troponin-T (cTn-T) levels, DNA damage in cardiomyocytes, and histologic view of heart tissues were evaluated. In addition, glutathione (GSH) and malondialdehyde (MDA) levels were measured to determine the oxidative status of cardiac tissue after TRZ administration. Heart rate was decreased, PR interval was prolonged, and QRS and T amplitudes were decreased in 20 mg/kg TRZ-administered group compared to the control group. Serum AST and cTn-T levels were significantly increased in 10 and 20 mg/kg TRZ-administered rats with respect to control rats. DNA damage was significantly increased in these groups. Additionally, degenerative histopathologic findings were observed in TRZ-administered groups. Although there was no difference in MDA levels between groups, GSH levels were significantly decreased in 10 and 20 mg/kg TRZ-administered groups compared to the control group. Our results have shown that TRZ induced cardiotoxicity in rats dose-dependently. It is assumed that oxidative stress related to GSH depletion may be accompanied by these adverse effects.

Melatonin: A Versatile Protector against Oxidative DNA Damage

Oxidative damage to DNA has important implications for human health and has been identified as a key factor in the onset and development of numerous diseases. Thus, it is evident that preventing DNA from oxidative damage is crucial for humans and for any living organism. Melatonin is an astonishingly versatile molecule in this context. It can offer both direct and indirect protection against a wide variety of damaging agents and through multiple pathways, which may (or may not) take place simultaneously. They include direct antioxidative protection, which is mediated by melatonin's free radical scavenging activity, and also indirect ways of action. The latter include, at least: (i) inhibition of metal-induced DNA damage; (ii) protection against non-radical triggers of oxidative DNA damage; (iii) continuous protection after being metabolized; (iv) activation of antioxidative enzymes; (v) inhibition of pro-oxidative enzymes; and (vi) boosting of the DNA repair machinery. The rather unique capability of melatonin to exhibit multiple neutralizing actions against diverse threatening factors, together with its low toxicity and its ability to cross biological barriers, are all significant to its efficiency for preventing oxidative damage to DNA.

Infection, Oxidative Stress, and Changes in Circulating Regulatory T Cells of Heart Failure Patients Supported by Continuous-Flow Ventricular Assist Devices

The objective of this study was to investigate the changes in oxidative stress (OS) and circulating regulatory T cells (Tregs) of the immune system in patients supported by continuous-flow ventricular assist device (CF-VAD) with or without infection. We recruited 16 CF-VAD patients (5 with infection and 11 without infection) and 7 healthy volunteers. Generation of reactive oxygen species (ROS) from lymphocytes, superoxide dismutase (SOD) in erythrocyte, total antioxidant capacity (TAC), and oxidized low-density lipoprotein (oxLDL) in plasma were measured. Circulating Tregs were evaluated by flow cytometry. Heart failure (HF) patients had elevated OS than healthy volunteers as evident from higher lymphocyte ROS, elevated oxLDL, as well as depleted SOD and TAC levels. At baseline, HF patients had decreased percentage of Tregs (5.12 ± 1.5% vs. 8.14 ± 3.01%, p < 0.01) when compared with healthy volunteers. Postimplant patients with infection illustrated 35% and 44% rise in ROS and oxLDL, respectively, 31% decrease in TAC, and marked rise in percentage of Tregs (14.27 ± 3.17% vs. 9.38 ± 3.41%, p < 0.01) when compared with the patients without infection. Elevated OS and rise in Tregs were more prominent in CF-VAD patients with infection. In conclusion, OS and compromised immune system may be important indicators of systemic response of the body to CF-VAD among HF patients with infection.

Impact of Diabetes Mellitus on Outcomes in Patients Supported With Left Ventricular Assist Devices

Background

Diabetes mellitus (DM) is a risk factor for morbidity and mortality in patients with heart failure. The effect of DM on post–left ventricular assist device (LVAD) implantation outcomes is unclear. This study sought to investigate whether patients with DM had worse outcomes than patients without DM after LVAD implantation and whether LVAD support resulted in a better control of DM.

Methods and Results

We retrospectively reviewed 341 consecutive adults who underwent implantation of LVAD from 2007 to 2016. Patient characteristics and adverse events were studied and compared between patients with and without DM. One hundred thirty-one patients (38%) had DM. Compared with patients without DM, those with DM had higher rates of ischemic cardiomyopathy, LVAD implantation as destination therapy, and increased baseline body mass index. In a proportional hazards (Cox) model with adjustment for relevant covariates and median follow-up of 16.1 months, DM was associated with increased risk of all-cause mortality (hazard ratio, 1.73; 95% confidence interval: 1.18–2.53; P =0.005) and increased risk of nonfatal LVAD-related complications, including a composite of stroke, pump thrombosis, and device infection (hazard ratio, 2.1; 95% confidence interval: 1.35–3.18; P =0.001). Preoperative hemoglobin A1c was not significantly associated with mortality or adverse events among patients with DM. LVAD implantation resulted in a remarkable decrease in hemoglobin A1c levels (7.4±1.9 pre-LVAD versus 6.0±1.5 and 6.3±1.4 after 3 and 12 months post-LVAD, respectively; P <0.0001) and a significant reduction in requirements of DM medications.

Conclusions

DM is associated with increased rates of all-cause mortality and major adverse events despite favorable glycemic control after LVAD implantation.

Oxidative stress induced modulation of platelet integrin α2bβ3 expression and shedding may predict the risk of major bleeding in heart failure patients supported by continuous flow left ventricular assist devices

INTRODUCTION

Oxidative stress and platelet integrin α2bβ3 plays important role in the process of hemostasis and thrombosis. We hypothesized that device-induced patient specific oxidative stress and integrin α2bβ3 shedding may be linked to major bleeding complication (MBC) in heart failure (HF) patients supported by continuous flow left ventricular assist devices (CF-LVADs).

MATERIALS AND METHODS

We recruited 47patients implanted with CF-LVADs and 15 healthy volunteers. Fourteen patients developed MBC (bleeder group) within one month after implantation while others were considered non-bleeder group (n=33). Oxidative stresses were evaluated by measuring reactive oxygen species (ROS) in platelets, superoxide dismutase (SOD) activity, total antioxidant capacity (TAC) and oxidized low density lipoprotein (oxLDL). Assessments of α2bβ3 were carried out using flow cytometry and ELISA.

RESULTS

Biomarkers of oxidative stress and α2bβ3 shedding (decreased surface expression and higher plasma levels) were found to be preexisting condition in all HF patients prior to CF-LVAD implantation compared to the healthy volunteers. Significantly elevated levels of ROS and oxLDL; concomitant depletion of SOD and TAC; and α2bβ3 shedding were observed in the bleeder group temporarily in comparison to the non-bleeder group after CF-LVAD implantation. A significantly strong association between α2bβ3 shedding and biomarkers of oxidative stress was observed; suggesting a potential role of oxidative stress in platelet integrin shedding leading to MBC after CF-LVAD implantation. Moreover, a receiver operating characteristic (ROC) analysis indicated that the likelihood of MBC data from Integrin α2bβ3 shedding had a predictive power of MBC in CF-LVAD patients.

CONCLUSIONS

Oxidative stress might play a potential role in accelerating α2bβ3 shedding and platelet dysfunction, resulting in MBC in CF-LVAD patients. Integrin α2bβ3 shedding may be used to refine bleeding risk stratification in CF-LVAD patients.

DISPOSITIVOS DE ASSISTÊNCIA VENTRICULAR E CUIDADOS DE ENFERMAGEM

RESUMO Objetivo: descrever o funcionamento, os benefícios e as complicações associadas ao uso de dispositivos de assistência ventricular e identificar as intervenções realizadas por enfermeiros no cuidado ao paciente com este dispositivo, de acordo com as evidências. Método: revisão integrativa, com artigos coletados em bases de dados da saúde, em fevereiro de 2015. Os descritores utilizados foram heart diseases, heart-assist devices e nursing. Identificaram-se 34 artigos, os quais foram submetidos à análise temática. Resultados: os dispositivos de assistência ventricular funcionam como bombas mecânicas promotoras de débito cardíaco adequado. Seu principal benefício é a estabilização hemodinâmica. A complicação mais comum é a infecção. Educação em saúde, suporte emocional, cuidados com sítio de saída e realização de curativo são os principais cuidados realizados por enfermeiros. Conclusão: as evidências comprovam a melhoria da sobrevida de pacientes com insuficiência cardíaca grave com o uso dos dispositivos de assistência ventricular, reiterando a importância da ampliação dessa tecnologia no Brasil como possibilidade de tratamento.

Endosulfan induces cell dysfunction through cycle arrest resulting from DNA damage and DNA damage response signaling pathways

Our previous study showed that endosulfan increases the risk of cardiovascular disease. To identify toxic mechanism of endosulfan, we conducted an animal study for which 32 male Wistar rats were randomly and equally divided into four groups: Control group (corn oil only) and three treatment groups (1, 5 and 10mgkg^-1·d^-1). The results showed that exposure to endosulfan resulted in injury of cardiac tissue with impaired mitochondria integrity and elevated 8-OHdG expression in myocardial cells. Moreover, endosulfan increased the expressions of Fas, FasL, Caspase-8, Cleaved Caspase-8, Caspase-3 and Cleaved Caspase-3 in cardiac tissue. In vitro, human umbilical vein endothelial cells (HUVECs) were treated with different concentrations of endosulfan (1, 6 and 12μgmL^-1) for 24h. An inhibitor for Ataxia Telangiectasia Mutated Protein (ATM) (Ku-55933, 10μM) was added in 12μgmL^-1 group for 2h before exposure to endosulfan. Results showed that endosulfan induced DNA damage and activated DNA damage response signaling pathway (ATM/Chk2 and ATR/Chk1) and consequent cell cycle checkpoint. Furthermore, endosulfan promoted the cell apoptosis through death receptor pathway resulting from oxidative stress. The results provide a new insight for mechanism of endosulfan-induced cardiovascular toxicity which will be helpful in future prevention of cardiovascular diseases induced by endosulfan.

Phosphorylation of Histone H2A.X in Peripheral Blood Mononuclear Cells May Be a Useful Marker for Monitoring Cardiometabolic Risk in Nondiabetic Individuals

Phosphorylation of H2A.X (serine 139) in the histone H2A family located in the downstream of the DNA damage kinase signaling cascade is an important indicator of DNA damage. Recently, phosphorylation of H2A.X was proposed as a sensitive biomarker of aging. This study investigated if phosphorylation of H2A.X in peripheral blood mononuclear cells (PBMCs) is associated with cardiometabolic risk in nondiabetic individuals. Basic parameters and oxidative stress/inflammatory markers were measured in nondiabetic healthy Koreans (n = 119). Phosphorylation of H2A.X was measured randomly among the study subjects using a flow cytometer. According to the number of metabolic syndrome risk factor (MetS-RF), the study subjects were subdivided into “super healthy” (MetS − RF = 0, n = 71) and “MetS-risk” (MetS − RF ≥ 1, n = 48) groups. Phosphorylation of H2A.X in PBMCs (percentages and mean fluorescence intensity) was significantly higher in the MetS-risk group than in the super healthy group after adjusting for age, sex, cigarette smoking, and alcohol consumption. Phosphorylated H2A.X was positively correlated with the number of MetS-RF as well as waist circumference, blood pressures, triglyceride, Hb_A1C, oxidized LDL, high sensitivity C-reactive protein, tumor necrosis factor-alpha, and alanine aminotransferase after the adjustment. The present study suggested that phosphorylated H2A.X in circulating PBMCs measured by flow cytometer may be a useful marker for monitoring cardiometabolic risk in nondiabetic individuals.

A Therapeutic Effects of Atorvastatin on Genetic Damage in Coronary Artery Disease

INTRODUCTION

Coronary Artery Disease (CAD) a multifactorial chronic heart disease and the most frequent cause of death and disabling symptoms worldwide, occurs due to the formation of atheromatous lipid rich plaques in the arteries. Statins, which inhibit cholesterol biosynthesis, have both pleiotropic and Low-Density Lipoprotein (LDL)-lowering properties. Atorvastatin is one of the choices for the primary and secondary prevention of cardiovascular disease and management of hypercholesterolaemia. However, there is a paucity of data regarding the changes in the DNA damage in patients with coronary atherosclerosis after statin use.

AIM

The aim of the present study was to evaluate atorvastatin treatment efficacy on lipid profiles and DNA damage in CAD patients.

MATERIALS AND METHODS

The current observational study was conducted on 180 CAD patients between November 2011 to December 2013 at Durgabai Deshmukh Hospital and Research Centre, Vidya Nagar, Hyderabad, India. Atorvastatin administered and blood samples were collected at index hospitalization and after 6 months statin therapy and lipid profiles and DNA damage was compared with 200 healthy control.

RESULTS

Lipid profiles and DNA damage were found to be significantly high (p < 0.01) in CAD patients before atorvastatin therapy compared to after 6 months statin therapy and healthy controls.

CONCLUSION

The study suggests that atorvastatin might help in regression of lipid profile as well as DNA damage of CAD patients.

Increased risk of cardiovascular disease in premenopausal female ragpickers of Eastern India: involvement of inflammation, oxidative stress, and platelet hyperactivity

Millions of poor people in the developing world still thrive on ragpicking. In the present study, we have examined whether ragpicking is associated with increased risk of cardiovascular disease. For this, we have enrolled 112 premenopausal female ragpickers (median age 30 years) and 98 age-matched housemaids as control from Kolkata, Eastern India. Venous blood was drawn for routine hematology; flow cytometry was used to measure generation of reactive oxygen species (ROS) by leukocytes, surface expression of CD62P (P-selectin) in platelets and CD11b in leukocytes. Collagen-induced platelet aggregation was evaluated by aggregometer, and erythrocytic superoxide dismutase (SOD) was measured by spectrophotometry. Soluble P-selectin (sP-sel) and CD40L (sCD40L), neutrophil-activating protein-2 (NAP-2), platelet and plasma serotonin, oxidized low-density lipoprotein (oxLDL), and anticardiolipin antibodies (aCL) in plasma were measured by ELISA. Compared with control, the ragpickers had significantly higher prevalence of hypertension and prehypertension, and hypertension was positively associated with ragpicking. The ragpickers also had higher levels of inflammation (elevated NAP-2), oxidative stress (elevated ROS generation with depleted SOD) with oxLDL, platelet activation and aggregability, soluble CD40 ligand, with altered serotonin level (rose in plasma but depleted in platelet). A greater percentage of ragpickers had elevated serum level of aCL of the IgG and IgM isotypes than the controls. The results suggest that the occupation of ragpicking increases the risk of cardiovascular diseases in premenopausal women of Eastern India via inflammation, oxidative stress, platelet hyperactivity, and hypertension.

Comparison of intraplatelet reactive oxygen species, mitochondrial damage, and platelet apoptosis after implantation of three continuous flow left ventricular assist devices: HeartMate II, Jarvik 2000, and HeartWare

Differences in device design may have an effect on platelet damage and associated clinical complications. We aimed to compare device-specific platelet functionality in 26 heart failure patients supported with three continuous-flow left ventricular assist devices: HeartMate II (n = 8), Jarvik 2000 (n = 9), and HeartWare (n = 9). Intraplatelet reactive oxygen species (ROS) generation, mitochondrial damage, and platelet apoptosis were compared between device types before and after the implantation at every week up to 1 month. Overall, the baseline characteristics, demographics, routine laboratory values were comparable between the three device groups. Intraplatelet ROS, mitochondrial damage, and platelet apoptosis significantly elevated in the HeartWare group in comparison with the other two device groups after implantation. The major bleeding, infections, systemic inflammatory response syndrome, and right ventricular failure were found to be more common among the HeartWare group than others. Intraplatelet ROS and platelet damage levels were returned to baseline in both the HeartMate II and the Jarvik groups, whereas in HeartWare group they remained elevated. The patients with the Jarvik and the HeartMate II experienced less clinical complications and the platelet functionality is not compromised by these devices. Data from this study suggests that the continuous-flow left ventricular assist devices design may exert different effects on platelet function.

Association of -77T>C and Arg194trp polymorphisms of XRCC1 with risk of coronary artery diseases in Iranian population

OBJECTIVES

Coronary artery disease (CAD) is the leading cause of death in both male and female worldwide. The main cause of CAD is the atherosclerosis of coronary arteries, which is, mostly caused by genetic alteration. 50% of such cases occur in mitotic cells where single-strand breaks occur spontaneously or due to ionizing radiation. X-ray repair cross-complementing protein 1 (XRCC1) as a key element, participate in the base excision repair (BER) and Single-strand Break Repair (SSBR) pathways. It has been suggested that XRCC1 functions as a scaffold protein able to coordinate and facilitate the various steps of DNA repair pathways. Two Single Nucleotide Polymorphisms (SNPs) (Arg194Trp and -77T>C) were reported to affect the function and expression of XRCC1, respectively.

MATERIALS AND METHODS

A case-control study was performed to investigate the relation between these polymorphisms and the CAD development. A population of 406 individuals was screened for SNPs by Restriction Fragment Length Polymorphisms (RFLP) method.

RESULTS

XRCC1 Arg194Trp polymorphism was associated with increased risk of CAD in examined population under a dominant model (Odds-ratio=2.604, P-value=0.001). Also the SNP of -77T>C revealed a protective role in the population under a dominant model (Odds-ratio=0.618, P-value=0.032).

CONCLUSION

Our findings demonstrated a contributory role of these two SNPs in CAD. Furthermore, our results support the role of DNA damages and the malfunctions of DNA repair system in cardiovascular disease development in Iranian patients.

Systemic Inflammatory Response Syndrome in End-Stage Heart Failure Patients Following Continuous-Flow Left Ventricular Assist Device Implantation: Differences in Plasma Redox Status and Leukocyte Activation

The role of oxidative stress and leukocyte activation has not been elucidated in developing systemic inflammatory response syndrome (SIRS) in heart failure (HF) patients after continuous-flow left ventricular assist device (CF-LVAD) implantation. The objective of this study was to investigate the change of plasma redox status and leukocyte activation in CF-LVAD implanted HF patients with or without SIRS. We recruited 31 CF-LVAD implanted HF patients (16 SIRS and 15 non-SIRS) and 11 healthy volunteers as the control. Pre- and postimplant blood samples were collected from the HF patients. Plasma levels of oxidized low-density lipoprotein (oxLDL), malondialdehyde (MDA), total antioxidant capacity (TAC), superoxide dismutase (SOD) in erythrocyte, myeloperoxidase (MPO), and polymorphonuclear elastase (PMN-elastase) were measured. The HF patients had a preexisting condition of oxidative stress than healthy controls as evident from the higher oxLDL and MDA levels as well as depleted SOD and TAC. Leukocyte activation in terms of higher plasma MPO and PMN-elastase was also prominent in HF patients than controls. Persistent oxidative stress and reduced antioxidant status were found to be more belligerent in HF patients with SIRS after the implantation of CF-LVAD when compared with non-SIRS patients. Similar to oxidative stress, the activation of blood leukocyte was significantly highlighted in SIRS patients after implantation compared with non-SIRS. We identified that the plasma redox status and leukocyte activation became more prominent in CF-LVAD implanted HF patients who developed SIRS. Our findings suggest that plasma biomarkers of oxidative stress and leukocyte activation may be associated with the development of SIRS after CF-LVAD implant surgery.

Is a palpable pulse always restored during cardiopulmonary resuscitation in a patient with a left ventricular assist device?

End-stage heart failure patients are being supported with continuous flow left ventricular assist devices (CF-LVAD) in increasing numbers. The severe physiologic and pharmacologic derangements associated with end-stage heart failure therapies predispose these patients to delirium. During a delirious episode, a patient may inadvertently disconnect CF-LVAD equipment, which may have dangerous consequences. Unfortunately, it is not yet routine to use readily available clinical monitoring tools to allow early detection of delirium in this high-risk population. The authors present a case of acute hyperactive delirium leading to pump power disconnection and cardiopulmonary arrest occurring 7 days after CF-LVAD implantation. The case highlights the need for delirium awareness in the cardiovascular intensive care unit and the unique challenges associated with resuscitation of CF-LVAD patients. The authors propose that cardiovascular intensive care unit patients undergo at least twice daily delirium monitoring and provide a novel resuscitation algorithm for patients who have CF-LVADs.