Tobacco Smoke Exposure in Either the Donor or Recipient Before Transplantation Accelerates Cardiac Allograft Rejection, Vascular Inflammation, and Graft Loss

Early Use of Aspirin for Coronary Allograft Prophylaxis in Heart Transplant Recipients

BACKGROUND

Coronary allograft vasculopathy (CAV) remains a significant cause of morbidity and mortality after heart transplantation. The use of aspirin for CAV prophylaxis has recently garnered interest as a possible therapeutic adjunct in this setting.

METHODS

This 2-center retrospective cohort study included 372 patients who underwent heart transplantation between January 2009 and March 2018 and were stratified according to the commencement of aspirin during their index transplant admission. The primary outcome was the development of moderate or severe CAV (International Society for Heart and Lung Transplantation grade ≥2) at surveillance coronary angiography. Secondary endpoints included mortality at follow-up.

RESULTS

There were no differences in age, sex, and cause of heart failure. In the early aspirin group, the preponderant risk factors included use of ventricular assist devices, pretransplant smoking, and mild or moderate rejection. Multivariable analyses to assess for independent predictors of CAV development and mortality demonstrated that aspirin was associated with reduced mortality (adjusted hazard ratio = 0.19; 95% confidence interval, 0.08-0.47, P  < 0.01) and a trend toward a protective effect against the development of moderate or severe CAV (adjusted hazard ratio = 0.24; 95% confidence interval, 0.54-1.19; P  = 0.08).

CONCLUSIONS

In this retrospective risk-adjusted 2-center cohort study, early aspirin administration was associated with reduced risk of death and a trend toward a protective effect against CAV development. These findings warrant validation in prospective randomized trials.

Prediction of cardiac allograft vasculopathy using splenic switch-off on myocardial PET

BACKGROUND

Heart transplantation (HTx) is a definitive therapy for refractory heart failure. Cardiac allograft vasculopathy (CAV), characterized by diffuse arteriopathy involving the epicardial coronary arteries and microvasculature, is the major cause of death for patients with HTx. 13N-ammonia positron emission tomography (NH3-PET) can offer diagnostic and prognostic utility for CAV. The splenic switch-off (SSO) detected in NH3-PET is a hemodynamic indicator of favorable response to adenosine. We hypothesized that both CAV and SSO reflected a pathology that progresses in parallel with systemic vascular endothelial dysfunction. Therefore, we quantitatively evaluated splenic adenosine reactivity measured using NH3-PET as an index of endothelial function, and examined its predictability for CAV.

METHODS

Forty-eight patients who underwent NH3-PET after HTx were analyzed. The spleen ratio was calculated as the mean standardized uptake value, measured by placing an ROI on the spleen, at stress divided by that at rest. SSO was defined by a cutoff determined using receiver operating characteristic (ROC) analysis for the spleen ratio. The endpoint was appearance or progression of CAV. Predictability of SSO was analyzed using Kaplan-Meier analysis.

RESULTS

The endpoint occurred in 9 patients during a mean follow-up of 45 ± 17 months. ROC curve analysis demonstrated a cutoff of 0.94 for spleen ratio. Patients without SSO displayed a significantly higher CAV rate than those with SSO (p = 0.022).

CONCLUSIONS

SSO reflects the endothelial function of systemic blood vessels and was a predictor of CAV in patients with HTx.

Impact of air pollution on postoperative outcomes following organ transplantation: Evidence from clinical investigations

INTRODUCTION

Air pollution is a worldwide problem affecting human health via various body systems, resulting in numerous significant adverse events. Air pollutants, including particulate matter < or = 2.5 microns (PM2.5), particulate matter < or = 10 microns (PM10), ozone (O3 ), nitrogen dioxide (NO2 ), and traffic-related air pollution (TRAP), have demonstrated the negative effects on human health (e.g., increased cerebrovascular, cardiovascular, and respiratory diseases, malignancy, and mortality). Organ transplant patients, who are taking immunosuppressive agents, are especially vulnerable to the adverse effects of air pollutants. The evidence from clinical investigation has shown that exposure to air pollution after organ transplantation is associated with organ rejection, cardiovascular disease, coronary heart disease, cerebrovascular disease, infection-related mortality, and vitamin D deficiency.

OBJECTIVES AND METHOD

This review aims to summarize and discuss the association of exposure to air pollutants and serum 25-hydroxyvitamin D level and outcomes after transplantation. Controversial findings are also included and discussed.

CONCLUSION

All of the findings suggest that air pollution results in a hazardous environment, which not only impacts human health worldwide but also affects post-transplant outcomes.

Donor substance abuse and heart transplantation outcomes

Heart failure continues to account for millions of cases and deaths worldwide. Heart transplant is the gold standard for treatment of advanced heart failure. Unfortunately, the supply of donor hearts continues to be limited with the increase in demand for heart transplantation. In this review, we aim to explore the safety and efficacy of using hearts from donors with history of substance use. Despite the theoretical effect of cocaine and alcohol on the cardiovascular system, several studies demonstrate no difference in outcomes (overall survival, graft rejection, graft vasculopathy) when using hearts from patients with history of cocaine and alcohol use. The opioid epidemic has expanded the potential donor pool where the current studies have not shown any adverse outcomes when considering donors with history of opioid use. The currently available evidence would support the use of donor hearts from patients with history of alcohol, cocaine, opioids, and marijuana use. Further studies are needed to evaluate the safety of using donor hearts from patients with history of nicotine use.

Statistical Bioinformatics to Uncover the Underlying Biological Mechanisms That Linked Smoking with Type 2 Diabetes Patients Using Transcritpomic and GWAS Analysis

Type 2 diabetes (T2D) is a chronic metabolic disease defined by insulin insensitivity corresponding to impaired insulin sensitivity, decreased insulin production, and eventually failure of beta cells in the pancreas. There is a 30–40 percent higher risk of developing T2D in active smokers. Moreover, T2D patients with active smoking may gradually develop many complications. However, there is still no significant research conducted to solve the issue. Hence, we have proposed a highthroughput network-based quantitative pipeline employing statistical methods. Transcriptomic and GWAS data were analysed and obtained from type 2 diabetes patients and active smokers. Differentially Expressed Genes (DEGs) resulted by comparing T2D patients’ and smokers’ tissue samples to those of healthy controls of gene expression transcriptomic datasets. We have found 55 dysregulated genes shared in people with type 2 diabetes and those who smoked, 27 of which were upregulated and 28 of which were downregulated. These identified DEGs were functionally annotated to reveal the involvement of cell-associated molecular pathways and GO terms. Moreover, protein–protein interaction analysis was conducted to discover hub proteins in the pathways. We have also identified transcriptional and post-transcriptional regulators associated with T2D and smoking. Moreover, we have analysed GWAS data and found 57 common biomarker genes between T2D and smokers. Then, Transcriptomic and GWAS analyses are compared for more robust outcomes and identified 1 significant common gene, 19 shared significant pathways and 12 shared significant GOs. Finally, we have discovered protein–drug interactions for our identified biomarkers.

Cigarette smoke and nicotine effects on behavior in HIV transgenic rats

HIV-related neurocognitive impairment can be worsened by cigarette smoking and be more severe in women. Therefore, we analyzed the effects of sex on behavioral function in HIV transgenic (Tg) rats that were exposed to either nicotine alone, to smoke from either nicotine-containing or nicotine-free cigarettes, or non-exposed. The animals were then assessed on the open field test for the total distance traveled and for the fraction of the total distance traveled and the total time spent in the center of the field, and the results then compared to WT rats subjected to the same exposures and testing. Higher total distances indicate greater locomotor activity and a higher center field measures imply a lower anxiety state. Total distances were overall higher for female and for Tg rats exposed to nicotine-free CS. Also, the total distance and both center field measures were overall higher for female rats in the control and nicotine-free CS-exposed groups. This was observed specifically for WT females as compared to WT males and, for the center field measures, for WT females as compared to Tg males. No genotype or sex-related differences were found for rats in the nicotine-free cigarette smoke (CS) and nicotine-containing CS exposed groups. Therefore, nicotine exposure did not impact genotype- and sex-related differences in motor responses and anxiety levels that were found in the control state. However, exposure to the non-nicotine components of CS resulted in locomotor activation in the presence of the HIV genes and was anxiogenic in WT and Tg male animals.

Non-immune risk predictors of cardiac allograft vasculopathy: Results from the U.S. organ procurement and transplantation network

BACKGROUND

Cardiac allograft vasculopathy (CAV) remains a major long-term complication in heart transplant (HT) recipients related to increased mortality. We aimed to identify non-immune recipient- and donor-related risk factors for the development of CAV in HT patients.

METHODS

40,647 recipients, prospectively enrolled from April 1995 to January 2019 in the Organ Procurement and Transplantation Network (OPTN), were analyzed after exclusion of pediatric patients, those with missing information on CAV, and re-transplantation. Multivariable-adjusted Cox regression analyses were performed to identify recipient- and donor-related risk factors for CAV. 5-year population attributable risk for classical cardiovascular risk factors was calculated to estimate the recipients' CAV risk. Analyses were based on OPTN data (June 30, 2019).

RESULTS

Of 40,647 post-transplant patients, 14,698 (36.2%) developed CAV with a higher incidence in males (37.3%) than in females (32.6%) (p < 0.001). The mean follow-up time was 68.2 months. In recipients, male sex, African American and Asian ethnicity, ischemic cardiomyopathy, body mass index and smoking were associated with CAV occurrence. In donors, older age, male sex, smoking, diabetes and arterial hypertension were related to CAV. Results remained fairly stable after analysis of different time periods. 5-year attributable CAV risk for classical cardiovascular risk factors was 9.1%.

CONCLUSIONS

In this large registry with known limitations concerning data completeness, CAV incidence was higher in males than in females. Next to male sex and donor age, the classical cardiovascular risk factors were related to incident CAV. Classical cardiovascular risk factors played only a minor role for the 5-year attributable CAV risk.

Impact of donor smoking history on post heart transplant outcomes: A propensity-matched analysis of ISHLT registry

PURPOSE

Smoking is a major public health issue, and its effect on cardiovascular outcomes is well established. This study evaluates the impact of donor smoking on heart transplant (HT) outcomes.

METHODS

HT recipients between January 1, 2005, and December 31, 2016, with known donor smoking status were queried from the International Society of Heart and Lung Transplantation (ISHLT) registry. The primary outcome was all-cause mortality, and secondary endpoints were graft failure, acute rejection, and cardiac allograft vasculopathy. We utilized propensity-score matching to identify cohorts of recipients with and without a history of donor smoking. Hazard ratios for post-transplant outcomes for the matched sample were estimated from separate Cox proportional hazard models.

RESULTS

Of 26 390 patients in the cohort, 18.9% had history of donor smoking. Donors with history of smoking were older, predominantly male and had higher incidence of diabetes, hypertension, cocaine use, and "high-risk" status. In propensity-matched analysis, recipients with a history of donor smoking had increased risk of death (HR 1.11, 95% CI 1.03-1.20) and higher risk of graft failure (HR 1.11, 95% CI 1.03-1.20).

CONCLUSION

Donor smoking was associated with increased mortality and higher incidence of graft failure following HT. Consideration of donor smoking history is warranted while evaluating donor hearts.

History of cigarette smoking and heart transplant outcomes

Background: Active cigarette smoking (CS) is a contraindication for Orthotopic Heart Transplantation (OHT) with a recommendation that HT candidates be free from CS for at minimum 6 months prior to HT. Animal studies have shown that a history of CS is associated with increased risk of allograft rejection, but few studies have examined the association of past CS and HT outcomes. Methods: Data were analyzed from HT recipients captured in the United Network for Organ Sharing (UNOS) transplant registry. Adults aged 18–79 who underwent HT from 1987 to 2018 and with data for all covariates (N = 32,260) were included in this study. The cohort was categorized by past smoking history (CS vs non-CS). Post-transplant outcomes of interest included survival, graft failure, treated rejection, malignancy and hospitalization for infection. Baseline characteristics were compared between the two groups using the chi-squared analysis. Unadjusted associations between CS and patient survival were determined using the Kaplan-Meier estimations and confounding was addressed using multivariable Cox proportional hazards models. Results: HT recipients with a history of CS were older (55 vs 50, p = <0.0001), more likely to be Caucasian (75.7 vs 62.3, p = <0.0001), male (81.7 vs 68.2, p =< 0.0001), and diabetic (27.4 vs 24.4, p =< 0.0001). CS was associated with significantly worse survival (HR: 1.23, p < 0.0001). A history of CS was also associated with increased risk of acute rejection (OR: 1.20, p < 0.0001), hospitalization for infection (OR:1.24, p < 0.0001), graft failure (OR:1.23, p < 0.0001) and post-transplant malignancy (OR:1.43, p < 0.0001). Conclusion: A history of CS is associated with increased risk of adverse events post OHT.

A Study of the Feasibility of FDG-PET/CT to Systematically Detect and Quantify Differential Metabolic Effects of Chronic Tobacco Use in Organs of the Whole Body-A Prospective Pilot Study

RATIONALE AND OBJECTIVES

The aim of this study was to assess the feasibility of ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) to systematically detect and quantify differential effects of chronic tobacco use in organs of the whole body.

MATERIALS AND METHODS

Twenty healthy male subjects (10 nonsmokers and 10 chronic heavy smokers) were enrolled. Subjects underwent whole-body FDG-PET/CT, diagnostic unenhanced chest CT, mini-mental state examination, urine testing for oxidative stress, and serum testing. The organs of interest (thyroid, skin, skeletal muscle, aorta, heart, lung, adipose tissue, liver, spleen, brain, lumbar spinal bone marrow, and testis) were analyzed on FDG-PET/CT images to determine their metabolic activities using standardized uptake value (SUV) or metabolic volumetric product (MVP). Measurements were compared between subject groups using two-sample t tests or Wilcoxon rank-sum tests as determined by tests for normality. Correlational analyses were also performed.

RESULTS

FDG-PET/CT revealed significantly decreased metabolic activity of lumbar spinal bone marrow (MVPmean: 29.8 ± 9.7 cc vs 40.8 ± 11.6 cc, P = 0.03) and liver (SUVmean: 1.8 ± 0.2 vs 2.0 ± 0.2, P = 0.049) and increased metabolic activity of visceral adipose tissue (SUVmean: 0.35 ± 0.10 vs 0.26 ± 0.06, P = 0.02) in chronic smokers compared to nonsmokers. Normalized visceral adipose tissue volume was also significantly decreased (P = 0.04) in chronic smokers. There were no statistically significant differences in the metabolic activity of other assessed organs.

CONCLUSIONS

Subclinical organ effects of chronic tobacco use are detectable and quantifiable on FDG-PET/CT. FDG-PET/CT may, therefore, play a major role in the study of systemic toxic effects of tobacco use in organs of the whole body for clinical or research purposes.

Matching the Market for Heart Transplantation

Heart transplantation is the most effective therapy for patients with Stage D heart failure with a median life expectancy of ≈10 to 15 years. Unfortunately, many patients die on the waiting list hoping for a chance of survival. The life boat cannot rescue everyone. Over a decade, the donor pool has remained relatively stable, whereas the number of heart transplant candidates has risen. Potential recipients often have many comorbidities and are older because the criteria for heart transplantation has few absolute contraindications. Women, Hispanics, and patients with restrictive heart disease and congenital heart disease are more likely to die while awaiting heart transplantation than men, white patients, and those with either ischemic or dilated cardiomyopathy. To better match the market, we need to (1) increase the donor pool, (2) reduce the waitlist, and (3) improve the allocation system. This review article addresses all 3 options and compares strategies in the United States to those in other countries.

The Maternal Cytokine and Chemokine Profile of Naturally Conceived Gestations Is Mainly Preserved during In Vitro Fertilization and Egg Donation Pregnancies

This prospective longitudinal study aimed at comparing maternal immune response among naturally conceived (NC; n = 25), in vitro fertilization (IVF; n = 25), and egg donation (ED; n = 25) pregnancies. The main outcome measures were, firstly, to follow up plasma levels of interleukin (IL) 1beta, IL2, IL4, IL5, IL6, IL8, IL10, IL17, interferon gamma, tumor necrosis factor-alpha (TNFα), transforming growth factor-beta (TGFβ), regulated upon activation normal T-cell expressed and secreted (RANTES), stromal cell-derived factor 1 alpha (SDF1α), and decidual granulocyte-macrophage colony-stimulating factor (GM-CSF) during the three trimesters of pregnancy during the three trimesters of pregnancy; secondly, to evaluate if the cytokine and chemokine pattern of ED pregnant women differs from that of those with autologous oocytes and, thirdly, to assess if women with preeclampsia show different cytokine and chemokine profile throughout pregnancy versus women with uneventful pregnancies. Pregnant women in the three study groups displayed similar cytokine and chemokine pattern throughout pregnancy. The levels of all quantified cytokines and chemokines, except RANTES, TNFα, IL8, TGFβ, and SDF1α, rose in the second trimester compared with the first, and these higher values remained in the third trimester. ED pregnancies showed lower SDF1α levels in the third trimester compared with NC and IVF pregnancies. Patients who developed preeclampsia displayed higher SDF1α plasma levels in the third trimester.

Evolving concepts and treatment strategies for cardiac allograft vasculopathy

OPINION STATEMENT

The central event in the development of allograft vasculopathy is the inflammatory response to immune-mediated and nonimmune-mediated endothelial damage. This response is characterized by the release of inflammatory cytokines, upregulation of cell-surface adhesion molecules, and subsequent binding of leukocytes. Growth factors stimulate smooth muscle cell proliferation and circulating progenitor cells are recruited to sites of arterial injury leading to neointima formation. Because of its diffuse nature, intravascular ultrasound is more sensitive than angiography for early diagnosis. Proliferation signal inhibitors (PSIs) have the capacity to slow vasculopathy progression by inhibiting smooth muscle cell proliferation, but its side effects profile makes its use as a first line agent difficult. Retransplantation is still the only definitive therapy but is available only in selected cases. The current hope is that immunomodulation at the time of transplant could induce long-term tolerance and graft accommodation, leading to less vasculopathy.

Prevention and treatment of coronary artery vasculopathy

PURPOSE OF REVIEW

Cardiac allograft vasculopathy (CAV) is still one of the major causes of death following heart transplantation. Here, we review the recent advances in its prevention and treatment.

RECENT FINDINGS

Preventive measures comprise control of classical risk factors, prophylaxis against cytomegalovirus, avoidance of graft endothelial damage during heart transplantation, and prevention of acute rejection. These measures can be effective if begun early. The treatment options for established CAV are limited, percutaneous revascularization and coronary artery bypass graft only being viable for a minority of patients because of the diffuse nature of CAV. Retransplantation is the only definitive therapy for CAV and may be considered for suitable patients with advanced CAV and allograft dysfunction. One of the most promising developments in the recent years is the use of mTOR inhibitors, which can now be regarded as effective in preventing CAV in de novo patients; their role in the treatment of established CAV is still uncertain despite some encouraging recent findings.

SUMMARY

The implementation of measures and lifestyles that help prevent CAV should be a priority of postheart transplantation management. Research should urgently evaluate mTOR inhibitors for the treatment of established CAV.

Inflammation and oxidative stress induced by cigarette smoke in Lewis rat brains

Exposure to cigarette smoke has been associated with an increased risk of neurological diseases such as stroke, Alzheimer's disease and multiple sclerosis. In these studies, serum and brain sections from Lewis rats or those exposed to cigarette smoke and control rats were examined for evidence of increased inflammation and oxidative stress. Immunocytochemical staining of brain sections from CS-exposed rats showed increased expression of class II MHC and, in ELISA, levels of IFN-gamma and TNF-α were higher than for non-exposed rats. In polymerase chain reaction assays there was increased interferon-gamma, TNF-α, IL-1α, IL-1β, IL-23, IL-6, IL-23, IL-17, IL-10, TGF-β, T-bet and FoxP3 gene expression with CS exposure. There was also markedly elevated MIP-1α/CCL3, less prominent MCP-1/CCL2 and no elevation of SDF-1α gene expression. Analysis of samples from CS-exposed and control rats for anti-oxidant expression showed no significant difference in serum levels of glutathione and, in brain, similar levels of superoxide dismutase and decreased thioredoxin gene expression. In contrast, there was increased brain gene expression for the pro-oxidants iNOS and the NADPH components NOX4, dual oxidase 1 and p22(phox). Nrf2 expression, which is typically triggered as a secondary response to oxidative stress, was also increased in brains from CS-exposed rats with nuclear translocation of this protein from cytoplasm demonstrated in astrocytes in association with increased expression of the aryl hydrocarbon receptor gene, an Nrf2 target. These studies, therefore, demonstrate that CS exposure in these animals can trigger multiple immune and oxidative responses that may have important roles in the pathogenesis of CNS inflammatory neurological diseases.

Cigarette smoking: a risk factor for postoperative morbidity and 1-year mortality following craniotomy for tumor resection

Object

Identifying risk factors for surgical morbidity and mortality might improve the safety and efficacy of neurosurgical intervention. Cigarette smoking is a relatively common practice and is associated with several adverse health outcomes. The authors examined the relationship between smoking and intraoperative blood loss, postoperative outcomes, and survival following craniotomy for tumor resection.

Methods

A consecutive population of patients undergoing craniotomy for tumor resection between 2006 and 2009 was identified. Using multivariable models and Cox proportional hazard regression analysis, the authors assessed the relation between smoking and operative outcomes including blood loss, complication rates, hospital length of stay, 30-day mortality, and 1-year survival among patients who underwent craniotomy for tumor resection.

Results

A total of 453 patients were included in this study: 237 patients never smoked, 54 quit smoking for at least 1 year, and 162 were current smokers. Current smoking status was an independent risk factor for higher intraoperative blood loss, complication risk, and lower 1-year survival following intervention relative to patients who never smoked. Patients who quit smoking had significantly higher mean blood loss, but did not carry a higher risk for other outcomes such as postoperative complications and 1-year mortality compared with patients who never smoked.

Conclusions

Current cigarette smoking is associated with poor surgical outcome and lower 1-year survival after undergoing craniotomy for tumor resection. However, quitting smoking and implementing strict smoking cessation programs may help mitigate these risks. Future research might investigate mechanisms underlying these associations.

In the era of the universal use of statins dyslipidemia's are still common in heart transplant recipients: a cross-sectional study

BACKGROUND

Statins are used in orthotopic heart transplant (OHT) recipients to avoid acute rejection episodes (ARE) during the first year after surgery and coronary vasculopathy (CAV) thereafter as established in prospective randomized trials, yielding the grounds for the universal use of this group of drugs. The aim of the study was to describe the occurrence of dyslipidemias among OHT recipients after introduction of guidelines suggesting the use of statins in all individuals able to tolerate this therapy.

METHODS

Medical records of all OHT recipients undergoing routine clinical checkups between January and June 2010 were screened for the presence of dyslipidemia: total cholesterol>5 mmol/L; low-density lipoprotein (LDL)-cholesterol>3 mmol/L; triglycerides>1.65 mmol/L; high-density lipoprotein (HDL)<1 mmol/L in the serum. The study group consisted of 322 subjects including 265 males and 57 females of overall mean age of 53.6±12 and 7±4 years after OHT. There was coronary artery disease (CAD) before OHT in 113 (35%). The average number of ARE was 1.9±1.9 and CAV was diagnosed in 77 (24%) patients. There were 247 (77%) patients on statins. We analyzed clinical, ultrasound, and biochemical evaluations to characterize subjects with dyslipidemias.

RESULTS

At least one dyslipidemia was observed among 212 (66%) including hypercholesterolemia in 121 (38%), high LDL in 135 (42%), hypertriglyceridemia in 110 (34%), and low HDL in 48 (15%) patients. The subjects with dyslipidemia were prone to be older, to have CAD before OHT, and to be hypertensive, overweight, and obese, as well as display an higher HbA1C when diabetic. They were treated less frequently with tacrolimus but showed higher drug levels, and more often were prescribed everolimus.

CONCLUSIONS

Despite almost universal use of statins, dyslipidemias were present in 2/3 of OHT recipients. It was related to typical atherosclerotic risk factors; however, the influence of immunosuppressants seemed to also be significant.

Antioxidant N-acetyl cysteine reverses cigarette smoke-induced myocardial infarction by inhibiting inflammation and oxidative stress in a rat model

The contribution of chronic tobacco exposure in determining post-myocardial infarction (MI) left ventricular (LV) remodeling and possible therapeutic strategies has not been investigated systematically. In this small animal investigation, we demonstrate that chronic tobacco smoke exposure leading up to acute MI in rats is associated with greater histological extent of myocardial necrosis and consequent worse LV function. These findings are associated with increased transcriptomic expression of pro-inflammatory cytokines, tissue repair molecules and markers of oxidative stress in the myocardium. The results demonstrate that an N-acetyl cysteine (NAC) treatment significantly reduced tobacco-exposed induced infarct size and percent fractional shortening. A significantly increased LV end-systolic diameter was observed in tobacco-exposed sham compared to tobacco-naïve sham (4.92±0.41 vs 3.45±0.33; P<0.05), and tobacco-exposed MI compared to tobacco-naïve MI (8.24±0.3 vs 6.1±0.49; P<0.01) rats. Decreased intracardiac mRNA expression of the markers of inflammation, tissue repair and oxidative stress and circulating levels of pro-inflammatory cytokines accompanied these positive effects of NAC. The treatment of tobacco-exposed MI rats with NAC resulted in significantly increased levels of intracardiac mRNA expression of antioxidants, including superoxide dismutase, thioredoxin and nuclear factor-E2-related factor 2, as well as circulating levels of glutathione (7±0.12 vs 10±0.18; P≤0.001), where the levels were almost identical to the tobacco-naïve sham rats. These findings identify a novel post-infarction therapy for amelioration of the adverse effects of tobacco exposure on the infracted myocardium and advocate the use of dietary supplement antioxidants for habitual smokers to prevent and reverse cardiovascular adverse effects in the absence of successful achievement of cessation of smoking.

In vitro assessment of tobacco smoke toxicity at the BBB: do antioxidant supplements have a protective role?

BACKGROUND

Tobacco smoke (TS) contains highly reactive oxygen species (such as hydrogen peroxide, peroxynitrite, etc), which cause oxidative damage in vascular tissue and may exacerbate inflammatory events leading to the blood-brain barrier damage (BBBD) which accompanies the development of a variety of neurological disorders. Smokers often have elevated leukocyte counts (primarily neutrophils and monocytes), and significant decreases in plasma alpha-tocopherol (vitamin E) and ascorbic acid (vitamin C) levels due to increased anti-oxidative mobilization in response to oxidative stress evoked by TS. For this purpose, using static culture systems and a well-established dynamic in vitro BBB model (DIV-BBB) we tested the hypothesis that antioxidant vitamin supplementation (E and/or C) can protect the BBB during exposure to whole soluble TS.

RESULTS

TS exacerbates inflammatory events and leads to endothelial overexpression of vascular adhesion molecules (VCAM-1, P-selectin and E-selectin), release of pro-inflammatory cytokines (TNF-α and IL-6) and nitric oxide (NO), release and activation of matrix metalloproteinases (MMP-2 and MMP-9), monocytic maturation into macrophages, and adhesion to the vascular endothelium. Furthermore, TS altered the normal glucose metabolic behaviour of in vitro BBB capillaries and caused a period of transient anaerobic respiration to meet the cellular bioenergetic demand. Pre-treatment with antioxidant vitamins (C and/or E) effectively reduced the pro-inflammatory activity associated with TS, protecting the viability and functions of the BBB.

CONCLUSION

Our results have shown that loss of endothelial viability as well as BBB function and integrity caused by TS exposure can be prevented or at least reduced by normal physiologic concentrations of antioxidant vitamins in vitro.

Cytokines present in smokers' serum interact with smoke components to enhance endothelial dysfunction

AIMS

Cigarette smoking engenders inflammation and endothelial dysfunction, processes implicated in atherothrombotic disease. We hypothesized that an interaction between inflammatory cytokines in smokers' blood and circulating components of cigarette smoke is necessary to induce reactive oxygen species (ROS) and cyclooxygenase-2 (COX-2) in endothelium. We then explored the molecular mechanisms involved in these effects.

METHODS AND RESULTS

Serum from nine healthy active smokers (AS) compared with serum from nine non-smokers (NS) showed higher levels of interleukin-1beta (IL-1β) and tumour necrosis factor-alpha (TNF-α) and a greater ability to induce ROS production, p47phox translocation to the plasma membrane, and COX-2 mRNA and protein expression in endothelial cells (ECs). Similar results were obtained in vivo and in vitro after treatment with aqueous extracts of cigarette smoke plus IL-1β and TNF-α(TS/IL-1β/TNF-α). In ECs increased ROS production and COX-2 mRNA induced by serum from AS correlated positively with their serum levels of IL-1β and TNF-α. Moreover, a positive correlation was observed between ROS generation and COX-2 mRNA. Simultaneous immuno-neutralization of IL-1β and TNF-α prevented endothelial dysfunction induced by serum from AS. Inhibitors of NADPH oxidase and/or p47phox siRNA diminished ROS production and COX-2 expression as well as phosphorylation of p38 mitogen-activated protein kinase (p38MAPK) and Akt mediated either by AS serum or by TS/IL-1β/TNF-α. Finally, direct inhibition of p38MAPK and Akt activity also abolished COX-2 expression mediated by both types of stimuli. Our results suggest a crucial role played by interactions between inflammatory cytokines and tobacco smoke in the induction of endothelial dysfunction.

Heart transplantation

PURPOSE OF REVIEW

This paper briefly and subjectively reviews a number of the modest or tentative, but noteworthy, advances in heart transplantation that have been made during the past 18 months or so.

RECENT FINDINGS

The advances reviewed concern the selection of recipients, the management of the heart transplantation waiting list, the management of donors, post-heart transplant monitoring of immunological status, the early diagnosis of rejection, the role of mammalian target of rapamycine inhibitors and induction agents, and the definition and grading of cardiac allograft vasculopathy.

SUMMARY

The findings reviewed indicate progress in the clarification of issues that were in most cases already being investigated. Further studies will in general be needed before corresponding measures are adopted in clinical practice.

Cardiac myocyte-specific overexpression of human GTP cyclohydrolase I protects against acute cardiac allograft rejection

GTP cyclohydrolase I (GTPCH) is the rate-limiting enzyme for tetrahydrobiopterin (BH(4)) synthesis. Decreases in GTPCH activity and expression have been shown in late stages of acute cardiac rejection, suggesting a deficit in BH(4). We hypothesized that increasing intracellular levels of BH(4) by cardiac myocyte-targeted overexpression of GTPCH would diminish acute cardiac allograft rejection. Transgenic mice overexpressing GTPCH in the heart were generated and crossed on C57BL6 background. Wild-type and transgenic mouse donor hearts were transplanted into BALB/c recipient mice. Left ventricular (LV) function, histological rejection, BH(4) levels, and inflammatory cytokine gene expression (mRNA) were examined. Expression of human GTPCH was documented by PCR, Western analysis, and function by a significant (P < 0.001) increase in cardiac BH(4) levels. GTPCH transgene decreased histological rejection (46%; P < 0.003) and cardiac myocyte injury (eosin autofluorescence; 56%; P < 0.0001) independent of changes in inflammatory cytokine expression or nitric oxide content. GTPCH transgene decreased IL-2 (88%; P < 0.002), IL-1R2 (42%; P < 0.0001), and programmed cell death-1 (67%; P < 0.0001) expression, whereas it increased fms-like tyrosine kinase 3 (156%; P < 0.0001) and stromal-derived factor-1 (2; 190%; P < 0.0001) expression. There was no difference in ejection fraction or fractional shortening; however, LV mass was significantly increased (P < 0.05) only in wild-type grafts. The decreases in LV mass, cardiac injury, and histological rejection support a protective role of cardiac GTPCH overexpression and increased BH(4) synthesis in cardiac allografts. The mechanism of the decreased rejection appears related to decreased T cell proliferation and modulation of immune function by higher expression of genes involved in hematopoietic/stromal cell development and recruitment.

Cigarette smoking, kidney function, and mortality after live donor kidney transplant

BACKGROUND

The role of smoking as a risk factor for adverse renal outcomes after kidney transplant has not been well studied. We therefore undertook this investigation to assess the association of smoking with transplant outcomes.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

997 consecutive laparoscopic live donor kidney transplant recipients at a tertiary-care transplant center.

PREDICTOR

Smoking at the time of the transplant evaluation.

OUTCOMES & MEASUREMENTS

Primary outcome is transplant survival.

RESULTS

At the time of pretransplant evaluation, 329 participants had ever smoked and 668 participants had never smoked. Transplant survival was worse in ever smokers compared with never smokers (adjusted HR, 1.47; 95% CI, 1.08-1.99; P = 0.01), as was patient survival (adjusted HR, 1.60; 95% CI, 1.06-2.41; P = 0.02). First-year rejection-free survival was substantially worse (adjusted HR, 1.46; 95% CI, 1.05-2.03; P = 0.03) and risk of rejection on or before posttransplant day 10 was much higher (adjusted HR, 1.8; 95% CI, 1.10-2.94; P = 0.02) in ever smokers compared with never smokers. Glomerular filtration rate (estimated using the Modification of Diet in Renal Disease Study equation) at 1 year posttransplant was lower and poor early transplant function was more common in ever smokers on univariate, but not multivariate, analysis.

LIMITATIONS

Lack of quantitation of smoking exposure and uncertainty about whether patients were still smoking at the time of transplant.

CONCLUSIONS

Our results suggest that any history of smoking before transplant is associated with impaired transplant and patient survival and increases the risk of early rejection after live donor kidney transplant. Further study is needed to determine whether smoking may impart immunomodulatory and perhaps nephrotoxic effects.