Janusz Kowalewski

Off-pump coronary artery bypass grafting improves short-term outcomes in high-risk patients compared with on-pump coronary artery bypass grafting: Meta-analysis

OBJECTIVES To assess the benefits and risks of off-pump coronary artery bypass (OPCAB) versus coronary artery bypass grafting (CABG) through a meta-analysis of randomized controlled trials (RCTs), and to investigate the relationship between outcomes and patient risk profile. METHODS PubMed, Embase, the Cumulative Index of Nursing and Allied Health Literature, Scopus, Web of Science, Cochrane Library, and major conference proceedings databases were searched for RCTs comparing OPCAB and CABG and reporting short-term (≤ 30 days) outcomes. Endpoints assessed were all-cause mortality, myocardial infarction (MI), and cerebral stroke. RESULTS The meta-analysis included 100 studies, with a total of 19,192 subjects. There was no difference between the 2 techniques with respect to all-cause mortality and MI (odds ratio [OR], 0.88; 95% confidence interval [CI], 0.71-1.09; P = .25; I(2) = 0% and OR, 0.90; 95% CI, 0.77-1.05; P = .19; I(2) = 0%, respectively). OPCAB was associated with a significant 28% reduction in the odds of cerebral stroke (OR, 0.72; 95% CI, 0.56-0.92; P = .009; I(2) = 0%). A significant relationship between patient risk profile and benefits from OPCAB was found in terms of all-cause mortality (P < .01), MI (P < .01), and cerebral stroke (P < .01). CONCLUSIONS OPCAB is associated with a significant reduction in the odds of cerebral stroke compared with conventional CABG. In addition, benefits of OPCAB in terms of death, MI, and cerebral stroke are significantly related to patient risk profile, suggesting that OPCAB should be strongly considered in high-risk patients.

Oxidative DNA damage and antioxidant vitamin level: Comparison among lung cancer patients, healthy smokers and nonsmokers

In the present study, we examined whether the level of 8‐oxo‐7,8‐dihydro‐2′‐deoxyguanosine (8‐oxodGuo) in leukocyte DNA is higher in lung cancer patients compared to controls. Factors that may influence oxidative stress, such as antioxidant vitamins, were also determined. These parameters were analyzed in 4 groups of subjects: smokers with lung cancer, ex‐smokers with lung cancer, healthy smokers with comparable smoking status and healthy nonsmokers. The 8‐oxodGuo mean level in leukocytes of lung cancer patients reached values of 9.22/106 dGuo molecules (smokers) and 11.16/106 dGuo molecules (ex‐smokers). These values were significantly higher than in DNA of healthy smokers and nonsmokers, where mean levels reached 6.99/106 dGuo molecules and 5.98/106 dGuo molecules, respectively. Mean levels of vitamin C in the plasma of controls and lung cancer patients were 56.17 μM (nonsmokers), 26.34 μM (healthy smokers), 23.83 μM (cancer patients, smokers) and 29.19 μM (cancer patients, ex‐smokers). The difference between nonsmokers and the 3 other groups was statistically significant. Vitamin E level was significantly reduced in the plasma of cancer patients (smokers 19.94 μM, ex‐smokers 19.59 μM) compared to healthy smokers (28.93 μM). No changes in vitamin A concentration were found. Our results suggest that a high level of 8‐oxodGuo in leukocyte DNA and a low concentration of vitamin E in the blood may predict lung cancer risk. However, it is also possible that these phenomena may simply result from disease development.

8-Oxoguanine incision activity is impaired in lung tissues of NSCLC patients with the polymorphism of OGG1 and XRCC1 genes.

Decreased repair of oxidative DNA damage is a risk factor for developing certain human malignancies. We have previously found that the capacity of 8-oxo-7,8-dihydroguanine repair was lower in leukocytes of NSCLC patients than in controls. To explain these observations, we searched for mutations and polymorphisms in the OGG1 gene among 88 NSCLC patients and 79 controls. One patient exhibited a heterozygous mutation in exon 1, which resulted in Arg46Gln substitution. Normal lung and tumor tissue carrying this mutation showed markedly lower 8-oxoG incision activity than the mean for all patients. The predominant polymorphism of OGG1 was Ser326Cys. A significant difference was observed in the frequencies of the OGG1 variants between populations of NSCLC patients and controls. The frequency of the Cys326 allele and the number of Cys326Cys homozygotes was higher among patients than controls. In individuals with either Ser326Cys or Cys326Cys genotype 8-oxoG incision rate was lower than in those with both Ser326 alleles, either in lung or leukocytes. Moreover, 8-oxodG level was higher in lung tissue and leukocytes of patients carrying two Cys326 alleles and in leukocytes of patients with the Ser326Cys genotype. We also screened for polymorphisms of the XRCC1 gene. Only heterozygotes of the XRCC1 variants Arg194Trp, Arg280His and Arg399Gln were found among patients and controls, with the frequency of Arg280His being significantly higher among patients. NSCLC patients with Arg280His or Arg399Gln polymorphism revealed lower 8-oxoG incision activity in their lung tissues, but not in leukocytes. We can conclude that the OGG1 Ser326Cys polymorphisms may have an impact on the efficiency of 8-oxoG incision in humans and the XRCC1 His280 and Gln399 may influence the OGG1 activity in tissues exposed to chronic oxidative/inflammatory stress. Higher frequency of the OGG1 Cys326 allele among NSCLC patients may partially explain the impairment of the 8-oxoG repair observed in their leukocytes.

Gentamicin-collagen sponge reduces the risk of sternal wound infections after heart surgery: Meta-analysis.

OBJECTIVES Sternal wound infections are serious postoperative complications that increase the length of hospital stay and healthcare costs. The benefit of implantable gentamicin-collagen sponges in reducing sternal wound infections has been questioned in a recent multicenter trial. We aimed to perform a comprehensive meta-analysis of studies assessing the efficacy of implantable gentamicin-collagen sponges in sternal wound infection prevention. METHODS Multiple databases were screened for studies assessing the efficacy of implantable gentamicin-collagen sponges after heart surgery. The primary end point was sternal wound infection, and secondary end points were the occurrence of deep sternal wound infection, superficial sternal wound infection, mediastinitis, and mortality. Randomized controlled trials and observational studies were analyzed separately. By means of meta-regression, we examined the correlation between sternal wound infection and extent to which the bilateral internal thoracic artery was harvested. RESULTS A total of 14 studies (N = 22,135, among them 4 randomized controlled trials [N = 4672]) were included in the analysis. Implantable gentamicin-collagen sponges significantly reduced the risk of sternal wound infection by approximately 40% when compared with control (risk ratio [RR], 0.61; 95% confidence interval [CI], 0.39-0.98; P = .04 for randomized controlled trials and RR, 0.61; 95% CI, 0.42-0.89; P = .01 for observational studies). A similar, significant benefit was demonstrated for deep sternal wound infection (RR, 0.60; 95% CI, 0.42-0.88; P = .008) and superficial sternal wound infection (RR, 0.60; 95% CI, 0.43-0.83; P = .002). The overall analysis revealed a reduced risk of mediastinitis (RR, 0.64; 95% CI, 0.45-0.91; P = .01). The risk of death was unchanged. A significant positive linear correlation (P = .05) was found between the log RR of sternal wound infection and the percentage of patients receiving bilateral internal thoracic artery grafts. CONCLUSIONS Implantable gentamicin-collagen sponges significantly reduce the risk of sternal wound infection after cardiac surgery, with evidence consistent in randomized and observational-level data. However, the extent of this benefit might be attenuated in patients receiving bilateral internal thoracic artery grafts.

Application of PCR methods to evaluate EGFR, KRAS and BRAF mutations in a small number of tumor cells in cytological material from lung cancer patients.

The epidermal growth factor receptor (EGFR) mutation status in the tyrosine kinase domain is known to be a predictor of the response to gefitinib or erlotinib in lung cancer; thus, a non-surgical procedure of tumor specimen collection is critical for mutation analysis. The aim of the present study was to analyze the EGFR, KRAS and BRAF status in limited cytological material. To the best of our knowledge, this is the first time that the quantitative scale of tumor cells and the percentage of tumor cells in cytological material were evaluated at the early stages of pathomorphological material qualification for EGFR, KRAS and BRAF mutation analysis. Our results revealed that even 100–1,000 tumor cells from fine needle aspiration (FNA) samples provided reliable results of mutation analysis when sensitive real-time polymerase chain reaction (PCR) methods were used. EGFR mutations were detected in 10% (7/71) and KRAS mutations were detected in 35% (19/54) of the lung adenocarcinoma cases. In addition, we reported the most common inhibiting mutation (p.T790M) found in coexistence with p.L858R in an FNA sample from a patient, for whom short-term improvement after erlotinib treatment was observed before further progression of the disease. Subsequently, mutual exclusion of EGFR and KRAS mutations was observed. Cytological samples with a small number of tumor cells obtained via FNA, endobronchial ultrasound (EBUS)-transbronchial needle aspiration (TBNA) or brushing are suggested to be used for diagnostic purposes after careful selection by cytopathologists and analysis using a validated, sensitive real-time PCR method.

Enkephalin, its precursor, processing enzymes, and receptor as part of a local opioid network throughout the respiratory system of lung cancer patients

Evidence is accumulating regarding the local opioid regulation of physiologic respiratory functions. However, anatomical evidence for a local opioid network of the respiratory system is scarce. In this study, tissue samples from 12 lung cancer patients undergoing lobectomy or pneumonectomy were examined immunohistochemically for the expression of the opioid network components met-enkephalin, the respective precursor proenkephalin, the key processing enzymes prohormone convertases 1 and 2, carboxypeptidase E, and the delta opioid receptor in different areas of human lung. Colocalization of proenkephalin with met-enkephalin, prohormone convertase 1, prohormone convertase 2, and carboxypeptidase E was demonstrated by double-immunofluorescence confocal microscopy in alveolar macrophages, submucosal glands, cancerous cells, and pulmonary neuroendocrine cells of bronchial epithelium. Corresponding delta opioid receptor was identified on cells of all these functionally relevant anatomical structures and on substance P-immunoreactive sensory nerve fibers arborizing within bronchial epithelium. Our findings provide evidence of a local opioid network, that is, the exact anatomical localization of proenkephalin, its functionally active peptide met-enkephalin, and the key processing enzymes as well as corresponding delta opioid receptor, linked to functionally important structures of the respiratory system. These findings encourage future studies to examine the functional role of local opioid peptides within the respiratory system.

Cerebrovascular Events After No-Touch Off-Pump Coronary Artery Bypass Grafting, Conventional Side-Clamp Off-Pump Coronary Artery Bypass, and Proximal Anastomotic Devices: A Meta-Analysis.

Background Off‐pump coronary artery bypass (OPCAB) has been shown to reduce the risk of neurologic complications as compared to coronary artery bypass grafting performed with cardiopulmonary bypass. Side‐clamping of the aorta while constructing proximal anastomoses, however, still carries substantial risk of cerebral embolization. We aimed to perform a comprehensive meta‐analysis of studies assessing 2 clampless techniques: aortic “no‐touch” and proximal anastomosis devices (PAD) for OPCAB. Methods and Results PubMed, CINAHL, CENTRAL, and Google Scholar databases were screened for randomized controlled trials and observational studies comparing “no‐touch” and/or PAD with side‐clamp OPCAB and reporting short‐term (≤30 days) outcomes: cerebrovascular accident and all‐cause mortality. A total of 18 studies (3 randomized controlled trials) enrolling 25 163 patients were included. Aortic “no‐touch” was associated with statistically lower risk of cerebrovascular accident as compared to side‐clamp OPCAB: risk ratio 95% CI: 0.41 (0.27–0.61); P<0.01; I2=0%. Event rates were 0.36% and 1.28% for “no‐touch” and side‐clamp OPCAB, respectively. No difference was seen between PAD and side‐clamp OPCAB: 0.71 (0.33–1.55); P=0.39; I2=39%. A trend towards increased 30‐day all‐cause mortality with PAD and no difference with “no‐touch” were observed when compared to side‐clamp OPCAB. In a subset analysis, “no‐touch” consistently reduced the risk of cerebrovascular accident regardless of patients’ baseline risk characteristics. A benefit with PAD was observed in low‐risk patients. Conclusions Aortic “no‐touch” technique was associated with nearly 60% lower risk of postoperative cerebrovascular events as compared to conventional side‐clamp OPCAB with effect consistent across patients at different risk.

The Use of a Two-Tiered Testing Strategy for the Simultaneous Detection of Small EGFR Mutations and EGFR Amplification in Lung Cancer

Lung cancer is the leading cause of cancer-related death worldwide. Recent progress in lung cancer diagnosis and treatment has been achieved due to a better understanding the molecular mechanisms of the disease and the identification of biomarkers that allow more specific cancer treatments. One of the best known examples of personalized therapy is the use of tyrosine kinase inhibitors, such as gefitinib and erlotinib, for the successful treatment of non-small-cell lung cancer patients selected based on the specific EGFR mutations. Therefore, the reliable detection of mutations is critical for the application of appropriate therapy. In this study, we tested a two-tiered mutation detection strategy using real-time PCR assays as a well-validated high-sensitivity method and multiplex ligation-dependent probe amplification (MLPA)-based EGFRmut+ assay as a second-tier standard-sensitivity method. One additional advantage of the applied MLPA method is that it allows the simultaneous detection of EGFR mutations and copy-number alterations (i.e., amplifications) in EGFR, MET and ERBB2. Our analysis showed high concordance between these two methods. With the use of this two-tier strategy, we reliably determined the frequency of EGFR mutations and EGFR, MET and ERBB2 amplifications in over 200 lung cancer samples. Additionally, taking advantage of simultaneous copy number and small mutation analyses, we showed a very strong correlation between EGFR mutations and EGFR amplifications and a mutual exclusiveness of EGFR mutations/amplifications with MET and ERBB2 amplifications. Our results proved the reliability and usefulness of the two-tiered EGFR testing strategy.

Quantitative analysis of free- circulating DNA in plasma of patients with resectable NSCLC

Objective: Minute amounts of free-circulating DNA are present in plasma of healthy individuals, whereas its increased concentration was observed in patients with malignant tumors including non-small cell lung cancer (NSCLC). This study aimed at demonstrating the potential usefulness of plasma DNA concentration monitoring in NSCLC patients for therapy effectiveness assessment throughout the treatment and follow-up period. Methods: Plasma DNA concentration was assessed in 50 NSCLC patients (stage I – IIIA) prior and following the radical treatment using real-time quantitative PCR method. 10 orthopedic patient undergoing hip joint surgery and 40 healthy volunteers comprised control groups. Results: NSCLC patients (8.02 ng/ml) demonstrated significantly higher mean plasma DNA concentration with respect to healthy controls (2.27 ng/ml; p < 0.0000). Drastic increase in plasma DNA levels up to mean 68.74 ng/ml was detected a week after primary tumor resection. Still, similar phenomenon was observed in patients subjected to orthopedic surgical treatment (from 3.00 to 28.38 ng/ml, p < 0.0015). Most resected NSCLC patients with no disease recurrence during 3- to 6-month follow-up demonstrated reduced plasma DNA levels (mean 2.77 ng/ml) with respect to their presurgical values, whereas in relapsed subjects plasma DNA levels were significant higher. Conclusion: Free-circulating DNA concentration in plasma was significantly higher in NSCLC patients versus healthy controls. Its drastic increase following radical NSCLC treatment was most likely due to the surgical trauma. Importantly, the kinetics of plasma free-circulating DNA seems to be a promising marker of long-term effects of radical surgery in NSCLC.

Local pulmonary opioid network in patients with lung cancer: a putative modulator of respiratory function

Recently, there has been growing interest in the opioid regulation of physiological respiratory function. However, evidence for a local opioid network that includes endogenous opioid peptides and their receptors is scarce. Tissue samples from patients with lung cancer were examined by immunohistochemistry to identify the components of the opioid network: beta-endorphin (END); its precursor, proopiomelanocortin (POMC); the key processing enzymes prohormone convertase 1 and 2; carboxypeptidase E; and ENDs corresponding opioid receptor, the mu-opioid receptor (MOR). Additionally, we tested pulmonary function parameters in a patient with advanced lung cancer after inhalation of nebulized morphine. Confocal immunofluorescence microscopy revealed that the opioid precursor POMC colocalizes with its active peptide END, key processing enzymes and MOR in alveolar macrophages, submucosal glands, cancerous cells, and pulmonary neuroendocrine cells within the bronchial epithelium. In addition, MOR was identified on sensory nerve endings within the bronchial epithelium. Furthermore, nebulized morphine improved pulmonary function parameters in advanced lung cancer. These findings provide evidence of a local opioid network in functionally important anatomical structures of the respiratory system; this network consists of all the machinery required for POMC processing into active peptides, such as END, and contains the receptors for END. Our findings indicate a need for further clinical trials to elucidate the modulatory function of peripheral endogenous opioids in the human lung.