Zalán Szántó

PKA-Bad-14-3-3 and Akt-Bad-14-3-3 signaling pathways are involved in the protective effects of PACAP against ischemia/reperfusion-induced cardiomyocyte apoptosis

The neuropeptide PACAP (pituitary adenylate cyclase activating polypeptide) and its receptors are widely expressed in the nervous system and various other tissues. PACAP has well-known anti-apoptotic effects in neuronal cell lines. Recent data suggest that PACAP exerts anti-apoptotic effects also in non-neuronal cells. The peptide is present in the cardiovascular system, and has various distinct effects. The aim of the present study was to investigate whether PACAP is protective against in vitro ischemia/reperfusion-induced apoptosis in cardiomyocytes. Cultured cardiomyocytes were exposed to 60 min ischemia followed by 120 min reperfusion. The addition of PACAP1-38 significantly increased cell viability and decreased the ratio of apoptotic cells as measured by MTT test and flow cytometry. PACAP induced the phosphorylation of Akt and protein kinase A. In the present study we also examined the possible involvement of Akt- and protein kinase A-induced phosphorylation and thus inactivation of Bad, a pro-apoptotic member of the Bcl-2 family. It was found that ischemia significantly decreased the levels of phosphorylated Bad, which was counteracted by PACAP. Furthermore, PACAP increased the levels of Bcl-xL and 14-3-3 protein, both of which promote cell survival, and decreased the apoptosis executor caspase-3 cleavage. All effects of PACAP1-38 were inhibited by the PACAP antagonist PACAP6-38. In summary, our results show that PACAP has protective effects against ischemia/reperfusion-induced cardiomyocyte apoptosis and provides new insights into the signaling mechanisms involved in the PACAP-mediated anti-apoptotic effects.

Effect of PACAP in Central and Peripheral Nerve Injuries

Pituitary adenylate cyclase activating polypeptide (PACAP) is a bioactive peptide with diverse effects in the nervous system. In addition to its more classic role as a neuromodulator, PACAP functions as a neurotrophic factor. Several neurotrophic factors have been shown to play an important role in the endogenous response following both cerebral ischemia and traumatic brain injury and to be effective when given exogenously. A number of studies have shown the neuroprotective effect of PACAP in different models of ischemia, neurodegenerative diseases and retinal degeneration. The aim of this review is to summarize the findings on the neuroprotective potential of PACAP in models of different traumatic nerve injuries. Expression of endogenous PACAP and its specific PAC1 receptor is elevated in different parts of the central and peripheral nervous system after traumatic injuries. Some experiments demonstrate the protective effect of exogenous PACAP treatment in different traumatic brain injury models, in facial nerve and optic nerve trauma. The upregulation of endogenous PACAP and its receptors and the protective effect of exogenous PACAP after different central and peripheral nerve injuries show the important function of PACAP in neuronal regeneration indicating that PACAP may also be a promising therapeutic agent in injuries of the nervous system.

PACAP Immunoreactivity in Human Malignant Tumor Samples and Cardiac Diseases

Pituitary adenylate cyclase activating polypeptide (PACAP) is a pleiotropic and multifunctional neuropeptide having important roles in various physiological processes. Recent trends in PACAP research point to the clinical introduction of PACAP or its analogs/fragments possibly in the near future. Recently, we have shown the presence of PACAP in human plasma, milk, placenta, and follicular fluid samples. However, relatively few data are available on PACAP in human tissues from patients with different disorders. The aim of the present study was to determine, by radioimmunoassay, the tissue level of PACAP38-like immunoreactivity (LI) and PACAP27-LI in different primary non-small cell lung cancer, colon tumor samples, and in cardiac muscle samples from patients suffering from ischemic heart disease and valvular disorders. We also labeled the PAC1 receptors in human cardiac cells. All samples showed significantly higher PACAP38-LI compared with PACAP27-LI. We found significantly lower levels of PACAP38-LI and PACAP27-LI in tumoral and peripheral samples compared with normal healthy tissue in both lung and colon cancers. Further investigations are necessary to describe the exact function of PACAP in oncogenesis. We showed that PACAP38-LI and PACAP27-LI are significantly higher in ischemic heart diseases compared with valvular abnormalities, suggesting that PACAP might play a role in ischemic heart disorders.

Expression of CD97 and Adhesion Molecules on Circulating Leukocytes in Patients Undergoing Coronary Artery Bypass Surgery

Objective: Leukocyte activation is thought to be responsible for the adverse effects and postoperative complications following cardiopulmonary bypass (CPB). A novel cell surface molecule, CD97, is a sensitive marker of leukocyte and primary lymphocyte activation. The present study aimed to determine the activation of different leukocyte subsets by comparing the expression of CD97 and adhesion molecules (CD11, CD18) in patients receiving coronary surgery with or without CPB. Methods: 30 patients were enrolled and scheduled for coronary bypass surgery under CPB (20 patients, group A) and with off-pump (OP) operation (10 patients, group B). Blood samples were taken before and during surgery, and over the following first week. Results: Here, we report an early decrease in CD97 expression of granulocytes (PMN) and monocytes (MC) followed by an intensive increase reaching the maximum on postoperative days 2 and 3 in patients operated with CPB. The rate of active CD97-positive lymphocytes showed a marked, gradual increase until postoperative day 3 and remained elevated up to day 7 after CPB. OP surgery resulted in moderate alteration in the presence of CD97 on PMN, MC and lymphocytes. The expression of adhesion molecules was similar to CD97 in all leukocyte subsets. Conclusion: The findings about CD97 expression suggest considerable leukocyte activation following coronary bypass with CPB compared to OP surgery. The collected data show that the lymphocytes are highly activated and involved in leukocyte sequestration after CPB. Moreover, the importance of CD97 in CPB-related inflammatory response can be stated.

Expression of the somatostatin receptor subtype 4 in intact and inflamed pulmonary tissues.

Somatostatin released from capsaicin-sensitive sensory nerves of the lung during endotoxin-induced murine pneumonitis inhibits inflammation and hyperresponsiveness, presumably via somatostatin receptor subtype 4 (sst4). The goal of the present study was to identify sst4 receptors in mouse and human lungs and to reveal its inflammation-induced alterations with real-time quantitative PCR, Western blot, and immunohistochemistry. In non-inflamed mouse and human lungs, mRNA expression and immunolocalization of sst4 are very similar. They are present on bronchial epithelial, vascular endothelial, and smooth-muscle cells. The sst4 receptor protein in the mouse lung significantly increases 24 hr after intranasal endotoxin administration as well as in response to 3 months of whole-body cigarette smoke exposure, owing to the infiltrating sst4-positivite mononuclear cells and neutrophils. In the chronically inflamed human lung, the large number of activated macrophages markedly elevate sst4 mRNA levels, although there is no change in acute purulent pneumonia, in which granulocytes accumulate. Despite mouse granulocytes, human neutrophils do not show sst4 immunopositivity. We provide the first evidence for the expression, localization, and inflammation-induced alterations of sst4 receptors in murine and human lungs. Inasmuch as tissue distribution of this receptor is highly similar, extrapolation of murine experimental results to human conditions might be possible.

Dynamism of NF-κB and AP-1 Activation in the Signal Transduction of Ischaemic Myocardial Preconditioning

Nuclear factor (NF)-ĸB and activation protein (AP)-1 transcription factors play an important role in the signal transduction of delayed ischaemic preconditioning (PC) leading to myocardial cytoprotection. Because the exact mechanism of the activation of these factors is still not clear, we aimed to monitor the time fluctuation of NF-ĸB and AP-1 induction in an in vivo animal model. Furthermore, we measured the induction rate of these factors using repeated cycles of PC. Following median thoracotomy, anaesthetized animals (24 New Zealand White rabbits) were subjected to ischaemic PC by occlusion of the left anterior descending coronary artery for 5 min. After 10 and 30 min, and 1, 2, 3 and 4 h of reperfusion, tissue samples were taken from the ischaemic myocardium, and the DNA binding activity of the transcription factors was measured with electrophoretic mobility shift assay. A further 12 animals were subjected to 2 ×, 3 × or 4 × 5-min ischaemic PC, and after a 30-min or 1-hour reperfusion period, we investigated the possible modulation of NF-ĸB and AP-1 induction. Our results show significant, biphasically increased NF-ĸB activity with peak levels at 30 min and 3 h of reperfusion in preconditioned myocardium. AP-1 increased monophasically, with the peak level at 1 h of reperfusion. Repeated PC stimuli enhanced the activity of both transcription factors analyzed, but there was no significant correlation between the number of cycles and the rate of activation. Our results show that the activation of NF-ĸB and AP-1 have a specific time curve, and the induction of these factors is only slightly influenced by the number of PC cycles.

Examination of PACAP-Like Immunoreactivity in Urogenital Tumor Samples

Numerous studies investigated the localization of pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptors in different tumors and described the effects of analogs on tumor growth to show its potential role in oncogenesis. Recently, our research group has found significantly lower levels of PACAP27-like immunorreactivity (LI) and PACAP38-LI in different human samples of primary small cell lung cancer and colon cancer compared to normal healthy tissues. There are only few human studies showing the presence of PACAP and its receptors in urogenital tumors; therefore, the aim of the present study was to compare PACAP-LI in different healthy and pathological human samples from urogenital organs (kidney, urinary bladder, prostate, testis) with radioimmunoassay (RIA) method. Similar to our earlier observations, the PACAP27-LI was significantly lower compared to PACAP38-LI in all samples. We did not find significant alterations in PACAP-LI between healthy and tumoral samples from the urinary bladder and testis. On the other hand, we found significantly lower PACAP38-LI level in kidney tumors compared with healthy tissue samples, and we showed higher PACAP27-LI in prostatic cancer compared to samples from benign prostatic hyperplasia. These data indicate that PACAP levels of different tissue samples are altered under pathological conditions suggesting a potential role of PACAP in the development of different urogenital tumors.

Complications after ultrasonic lung parenchyma biopsy: a strong note for caution

BackgroundThis study aimed to determine the possible cause for an unacceptable frequency of postresectional pneumothorax in cases of ultrasonic scalpel use without a further reinforcing maneuver in lung biopsy during video-assisted thoracic surgery (VATS).MethodsData for a series of 16 consecutive VATS lung biopsy patients (group A) in which a disturbingly high number of minor and medium complications occurred were compared with data for a group of 20 patients previously subject to the same ultrasonic lung biopsy method (group B) without complication.ResultsThe two groups were identical in terms of all significant factors considered in relation to ultrasonic scalpel biopsy. Six notable air leakage complications occurred among the 16 patients of group A. One patient needed redrainage while still in the hospital. Two other patients required readmission and redrainage. In 4 of the 16 cases, late pneumothorax was detected after a “silent” 48-h postoperative period prolonging their hospital stay. Altogether, three medium complications occurred in group A, as compared with none in group B. The drainage duration in group B was not significantly shorter than in group A . Multivariate analysis showed a significant difference in complications favoring group B (odds ratio, 1.88).ConclusionsA high postoperative air leakage rate was observed in a simple case series using an unsecured harmonic scalpel after a randomized trial of the same method in the same institute with a diametrically opposite outcome. The medium complication rate of 3 in 16 cases is unacceptable for a minor procedure such as lung biopsy. The two groups differed only in their thromboembolic prophylaxis protocol. Therefore, it is hypothesized that the recent introduction of low-molecular-weight heparin from day 1 may influence the complication rate. The authors’ observation calls for caution in use of the harmonic scalpel on lung tissue without reinforcing maneuvers (i.e., stitches or clips). To avoid unnecessary complications, operative technique adjustment is recommended.

A risk score to predict the incidence of prolonged air leak after video-assisted thoracoscopic lobectomy: An analysis from the European Society of Thoracic Surgeons database

Objective: The study objective was to develop an aggregate risk score for predicting the occurrence of prolonged air leak after video‐assisted thoracoscopic lobectomy from patients registered in the European Society of Thoracic Surgeons database. Methods: A total of 5069 patients who underwent video‐assisted thoracoscopic lobectomy (July 2007 to August 2015) were analyzed. Exclusion criteria included sublobar resections or pneumonectomies, lung resection associated with chest wall or diaphragm resections, sleeve resections, and need for postoperative assisted mechanical ventilation. Prolonged air leak was defined as an air leak more than 5 days. Several baseline and surgical variables were tested for a possible association with prolonged air leak using univariable and logistic regression analyses, determined by bootstrap resampling. Predictors were proportionally weighed according to their regression estimates (assigning 1 point to the smallest coefficient). Results: Prolonged air leak was observed in 504 patients (9.9%). Three variables were found associated with prolonged air leak after logistic regression: male gender (P < .0001, score = 1), forced expiratory volume in 1 second less than 80% (P < .0001, score = 1), and body mass index less than 18.5 kg/m2 (P < .0001, score = 2). The aggregate prolonged air leak risk score was calculated for each patient by summing the individual scores assigned to each variable (range, 0–4). Patients were then grouped into 4 classes with an incremental risk of prolonged air leak (P < .0001): class A (score 0 points, 1493 patients) 6.3% with prolonged air leak, class B (score 1 point, 2240 patients) 10% with prolonged air leak, class C (score 2 points, 1219 patients) 13% with prolonged air leak, and class D (score >2 points, 117 patients) 25% with prolonged air leak. Conclusions: An aggregate risk score was created to stratify the incidence of prolonged air leak after video‐assisted thoracoscopic lobectomy. The score can be used for patient counseling and to identify those patients who can benefit from additional intraoperative preventative measures.

Changes in PACAP immunoreactivity in human milk and presence of PAC1 receptor in mammary gland during lactation.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with widespread occurrence in the nervous system and peripheral organs, including the mammary gland. Previously, we have shown that PACAP38 is present in the human milk at higher levels than in respective blood samples. However, it is not known how PACAP levels and the expression of PAC1 receptor change during lactation. Therefore, the aim of our study was to investigate PACAP38-like immunoreactivity (PACAP38-LI) in human colostrums and transitional and mature milk during lactation and to compare the expression of PAC1 receptors in lactating and non-lactating mammary glands. We found that PACAP38-LI was significantly higher in human colostrum samples than in the transitional and mature milk. PACAP38-LI did not show any significant changes within the first 10-month period of lactation, but a significant increase was observed thereafter, up to the examined 17th month. Weak expression of PAC1 receptors was detected in non-lactating sheep and human mammary glands, but a significant increase was observed in the lactating sheep samples. In summary, the present study is the first to show changes of PACAP levels in human milk during lactation. The presence of PACAP in the milk suggests a potential role in the development of newborn, while the increased expressions of PAC1 receptors on lactating breast may indicate a PACAP38/PAC1 interaction in the mammary gland during lactation.