Aprotinin Impacts 8-Isoprostane after Coronary Artery Bypass Grafting.

BACKGROUND AND AIMS:: The lungs participate in the modulation of the circulating inflammatory factors induced by coronary artery bypass grafting. We investigated whether aprotinin-which has been suggested to interact with inflammation-influences lung passage of key inflammatory factors after coronary artery bypass grafting. MATERIAL AND METHODS:: A total of 40 patients undergoing coronary artery bypass grafting were randomized into four groups according to aprotinin dose: (1) high dose, (2) early low dose, (3) late low dose, and (4) without aprotinin. Pulmonary artery and radial artery blood samples were collected for the evaluation of calculated lung passage (pulmonary artery/radial artery) of the pro-inflammatory factors interleukin 6 and interleukin 8, 8-isoprostane, myeloperoxidase and the anti-inflammatory interleukin 10 immediately after induction of anesthesia (T1), 1 min after releasing aortic cross clamp (T2), 15 min after releasing aortic cross clamp (T3), 1 h after releasing aortic cross clamp (T4), and 20 h after releasing aortic cross clamp (T5). RESULTS:: Pulmonary artery/radial artery 8-isoprostane increased in patients with high aprotinin dose as compared with lower doses (1.1 range 0.97 vs 0.9 range 1.39, p = 0.001). The main effect comparing high aprotinin dose with lower doses was significant (F(1, 38) = 7.338, p = 0.01, partial eta squared = 0.16) further supporting difference in the effectiveness of high aprotinin dose for pulmonary artery/radial artery 8-isoprostane. CONCLUSION:: According to the pulmonary artery/radial artery equation, the impact of aprotinin on 8-isoprostane after coronary artery bypass grafting is dose dependent. Aprotinin may aid the lung passage of circulating factors toward a beneficial anti-inflammatory milieu.

The Impact of Lung Ventilation on Some Cytokines after Coronary Artery Bypass Grafting.

BACKGROUND AND AIMS: Cardiopulmonary bypass induces a systematic inflammatory response, which is partly understood by investigation of peripheral blood cytokine levels alone; the lungs may interfere with the net cytokine concentration. We investigated whether lung ventilation influences lung passage of some cytokines after coronary artery bypass grafting. MATERIAL AND METHODS: In total, 47 patients undergoing coronary artery bypass grafting were enrolled, and 37 were randomized according to the ventilation technique: (1) No-ventilation group, with intubation tube detached from the ventilator; (2) low tidal volume group, with continuous low tidal volume ventilation; and (3) continuous 10 cm H2O positive airway pressure. Ten selected patients undergoing surgery without cardiopulmonary bypass served as a referral group. Representative pulmonary and radial artery blood samples were collected for the evaluation of calculated lung passage (pulmonary/radial artery) of the pro-inflammatory cytokines (interleukin 6 and interleukin 8) and the anti-inflammatory interleukin 10 immediately after induction of anesthesia (T1), 1 h after restoring ventilation/return of flow in all grafts (T2), and 20 h after restoring ventilation/return of flow in all grafts (T3). RESULTS: Pulmonary/radial artery interleukin 6 and pulmonary/radial artery interleukin 8 ratios ( p = 0.001 and p = 0.05, respectively) decreased, while pulmonary/radial artery interleukin 10 ratio ( p = 0.001) increased in patients without cardiopulmonary bypass as compared with patients with cardiopulmonary bypass. CONCLUSIONS: The pulmonary/radial artery equation is an innovative means for the evaluation of cytokine lung passage after coronary artery bypass grafting. The mode of lung ventilation has no impact on some cytokines after coronary artery bypass grafting in patients treated with cardiopulmonary bypass.

Treatment of esophageal perforation in octogenarians: a multicenter study.

Esophageal perforation is associated with significant mortality, and this may markedly increase with advanced age. This multicenter study investigates this issue in patients older than 80 years. Data on 33 patients >80 years old who underwent conservative (10 patients), endoclip (one patient), stent grafting (11 patients), or surgical treatment (11 patients) for esophageal perforation were collected from nine centers. Surgical repair consisted of repair on drain in one patient, primary repair in seven patients, and esophagectomy in two patients. Among patients who underwent stent grafting, one required repeat stenting and another stent graft repositioning. One patient was converted to surgical repair after stent grafting. Thirteen patients (39.4%) died during the 30-day and/or in-hospital stay. Their mortality was significantly higher than in a series of patients<80 years old (13.0%, 21/161 patients, P=0.001). Three patients (30.0%) died after conservative treatment, one (100%) after treatment with endoclips, five (45.5%) after stent grafting, and four (36.4%) after surgical repair (P=0.548). Early survival with salvaged esophagus was 42.4% (conservative treatment: 70.0% endoclips 0%, stent grafting: 54.5%, and surgical repair: 54.5%, respectively, P=0.558). Estimated glomerular filtration rate<60 mL/minute/1.73 m2 (70.0% vs. 25.0%, P=0.043) and sepsis (100% vs. 32.1%, P=0.049) at presentation were associated with increased risk of early mortality in univariate analysis. Esophageal perforation in octogenarians is associated with very high early and intermediate high mortality irrespective of the treatment method used.

Postconditioning and remote postconditioning of ischemic rat cardiac grafts.

BACKGROUND: Global warm ischemia of transplanted cardiac grafts is associated with apoptosis and subsequent tissue necrosis. It is suggested that postconditioning (PostC) may ameliorate the early outcome of cardiac grafts after ischemia-reperfusion. We investigated whether PostC and remote postconditioning (RPostC) have a histopathologic impact after transplantation of warm ischemic rat cardiac grafts. MATERIALS AND METHODS: Thirteen rats were randomized to undergo either PostC or RPostC after heterotopic transplantation of ischemic cardiac grafts. Six rats without intervention besides transplantation served as controls (control). The recipient rats were sacrificed 24 h after transplantation to evaluate histopathology and apoptotic index. RESULTS: No significant differences were observed between the study groups in terms of graft heat shock protein 70 and oxygen radical absorbing capacity, an indicator of antioxidant capacity. While apoptosis and PCARB, a marker of protein oxidation and oxidative stress, decreased after RPostC (p < 0.05), contraction band necrosis was less prominent in both PostC and RPostC. CONCLUSION: Both PostC and RPostC have a histopathologic impact after 24 h of reperfusion of warm ischemic rat cardiac grafts.

Prolonged cardiac allograft survival using iodine 131 after human sodium iodide symporter gene transfer in a rat model.

BACKGROUND: Radioiodine is efficiently concentrated by tissues expressing the human sodium iodide symporter (hNIS). OBJECTIVE: To analyze the effects of iodine 131 on acute cardiac allograft rejection after ex vivo hNIS gene transfer in a rat model of cardiac allotransplantation. MATERIALS AND METHODS: Hearts from Brown Norway rats were perfused ex vivo either with UW (University of Wisconsin) solution (n = 9) or UW solution containing 1 x 10(9) pfu/mL of adenovirus 5 plus NIS (Ad-NIS) (n = 18). Donor hearts were transplanted heterotopically into the abdomen of Lewis rats, and recipients were treated on postoperative day 3 with either 15,000 microCi of (131)I or saline solution. The hearts were explanted when no longer beating, and were evaluated histologically for evidence of rejection and other changes. RESULTS: Grafts perfused with the Ad-NIS vector survived significantly longer in recipients injected with (131)I (mean [SD], 11.3 [1.9] days) compared with control animals not treated with (131)I (5.7 [0.65] days) (P < .001). Treatment with (131)I did not prolong graft survival in recipients of hearts that were not perfused with Ad-NIS (5.5 [1.0] vs 5.3 [0.8] days). In Ad-NIS (131)I-treated transplants, the level of myocardial damage on day 6 after surgery, when control hearts were rejected, was significantly lower (60.8 [28.0] vs 99.7 [0.8]; P < .05). CONCLUSION: Our findings indicate that (131)I, after NIS gene transfer, can effectively prolong cardiac allograft survival. To our knowledge, this is the first report of the use of NIS-targeted (131)I therapy in cardiac transplantation. Further studies are required to determine the mechanism of this effect and its potential for clinical application.

Ultrarapid Ki-67 immunostaining in frozen section interpretation of gliomas.

BACKGROUND: Astrocytic tumours, the most common gliomas, are often classified intraoperatively using standard morphological staining. The final diagnosis and grading of gliomas on paraffin wax sections is often assisted by Ki-67 immunohistochemistry, but standard immunostaining protocols take too long to be used intraoperatively. AIMS: To investigate a new rapid Ki-67 immunohistochemical test for its use in an intraoperative setting. METHODS: The new Ki-67 immunostaining (Ultrarapid-Ki67) method on frozen sections can be carried out in 10 minutes. Thirty four pilocytic and diffuse astrocytomas were immunostained by rapid Ki-67 and results were compared with corresponding MIB-1 staining, histological grading, and prognosis. RESULTS: The staining protocol was practical to perform and the results were morphologically and quantitatively indistinguishable from those after immunostaining with MIB-1, an antibody recognising Ki-67 in paraffin wax embedded tissue. A comparison of Ultrarapid-Ki67 and MIB-1 immunostaining of paraffin wax sections showed almost identical quantitative correlation in astrocytic gliomas (r = 0.916; p<0.001). The Ultrarapid-Ki67 indices (percentage of positive cells) of low grade (I/II) astrocytomas ranged from 0% to 6.1%, whereas those of representative high grade (III/IV) tumours were significantly higher (range, 5.6-45%; p<0.001). The best prognostic cutoff point for Ultrarapid-Ki67 was 7.5%, which divided diffuse grade II-IV astrocytomas into significantly differing subsets (p = 0.0008). CONCLUSION: Ultrarapid-Ki67 immunostaining is a useful adjunct to morphological diagnosis and grading of astrocytic tumours, and as a fast test (approximately 10 minutes for staining plus three to four minutes for scoring), it could be used in routine intraoperative diagnosis of gliomas and other neoplastic diseases.

Does technical failure of revascularization during coronary artery bypass grafting predict severity of poststernotomy mediastinitis?

BACKGROUND AND AIMS: To assess the impact of unsuccessful revascularization in relation to poststernotomy mediastinitis (PSM), which affects long-term outcome after coronary artery bypass grafting (CABG). MATERIAL AND METHODS: An active approach for the follow-up of PSM involved a step by step treatment protocol of conventional surgery and plastic reconstructive surgery. 47 patients treated for PSM after CABG were identified and further evaluated. Complete revascularization was considered unsuccessful when technical hazards were reported during CABG. When PSM subsided after thorough debridement and sternal refixation without plastic reconstructive surgery, such as omentoplasty or muscle transposition, PSM was categorized as mild PSM. If treatment required plastic reconstructive surgery, PSM was categorized as severe PSM. Preoperative coronary artery angiographic status and success of revascularization were compared to postoperative outcome in relation to mild and severe PSM. RESULTS: 36 patients suffered from mild PSM and 11 patients from severe PSM. Preoperative clinical status did not differ among patients. Two patients (4.3 %) died during hospitalization. The need for plastic reconstructive surgery was significant (p < 0.05) among patients with unsuccessful revascularization. 35 out of 41 patients (85 %) without problems of graft anastomosis during CABG (successful revascularization) were associated with mild PSM, whereas only 6 out of 41 patients (15 %) with successful revascularization during CABG required plastic reconstructive surgery (p < 0.05). Technical failure of graft anastomosis (3 cases) or poor outflow of internal thoracic artery (2 cases) were statistically associated with severe PSM. CONCLUSION: Technical failures of revascularization during CABG may delay recovery from PSM.

Apoptotic activity is increased in brain cortex infarct after hypothermic circulatory arrest in a porcine model.

OBJECTIVE: It has been shown that apoptosis contributes to neuronal cell death after ischemia, and we evaluated the degree of apoptotic activity occurring in brain cortex of pigs after hypothermic circulatory arrest (HCA). DESIGN: Thirty-one pigs underwent 75 min of HCA at 20 degrees C. Histological examination of the brain was performed, and slides of brain cortex were evaluated for apoptotic activity by the TUNEL method. RESULTS: Ten animals died during the first postoperative day and 21 survived until the seventh postoperative day. Brain cortex infarcts were found in animals that survived 7 days and these were included in this study. The median histopathological score among animals that died on the first postoperative day was 3.0 (range, 2-4), whereas it was 4.0 (range, 2-4) among survivors (p = 0.019). The apoptotic index was particularly high in the area of the infarct, whereas only a few TUNEL-stained cells were observed in noninfarcted areas. The apoptotic index was nil in all pigs that died in the first postoperative period, whereas it was 2.0 (range, 0-6) among the animals that survived until the seventh postoperative day (p < 0.0001). CONCLUSION: The apoptotic index was significantly increased in brain cortex infarcts of animals that survived 7 days after HCA, whereas only a few apoptotic cells were observed in noninfarcted areas of these animals as well as in animals that died on the first postoperative day. Further studies are required to elucidate the timing of development of brain infarction after HCA and whether neuroprotective strategies targeting the apoptotic process may mitigate brain damage.

Increased medial TUNEL-positive staining associated with apoptotic bodies is linked to smooth muscle cell diminution during evolution of abdominal aortic aneurysms.

Apoptosis has recently been identified as an important process in large vessel structural integrity. We examined whether the size of the abdominal aortic aneurysm might be associated with programmed cell death. We performed in situ labeling of the 3' ends of DNA fragments by apoptosis-associated endonucleases in 20 aneurysms, 10 controls with aortoiliac occlusive disease, and 4 controls with healthy aortas. Antibodies against a-smooth muscle actin were used to quantify smooth muscle cell alterations in the medial layer. Inflammatory cell characterization was made by using four monoclonal mouse antibodies (UCHL1, L26, PG-M1, and KP1). The results confirm the assumption that an apoptotic process may be of consequence for the loss of medial smooth muscle cells in the early evolution of an abdominal aortic aneurysm process.

Leukocyte filtration improves brain protection after a prolonged period of hypothermic circulatory arrest: A study in a chronic porcine model.

BACKGROUND: Ischemic cerebral injury follows a well-attested sequence of events, including 3 phases: depolarization, biochemical cascade, and reperfusion injury. Leukocyte infiltration and cytokine-mediated inflammatory reaction are known to play a pivotal role in the reperfusion phase. These events exacerbate the brain injury by impairing the normal microvascular perfusion and through the release of cytotoxic enzymes. The aim of the present study was to determine whether a leukocyte-depleting filter (LeukoGuard LG6, Pall Biomedical, Portsmouth, United Kingdom) could improve the cerebral outcome after hypothermic circulatory arrest. METHODS: Twenty pigs (23-30 kg) were randomly assigned to undergo cardiopulmonary bypass with or without a leukocyte-depleting filter before and after a 75-minute period of hypothermic circulatory arrest at 20 degrees C. Electroencephalographic recovery, S-100beta protein levels, and cytokine levels (interleukin 1beta, interleukin 8, and tumor necrosis factor alpha) were recorded up to the first postoperative day. Postoperatively, all animals were evaluated daily until death or until electively being put to death on day 7 by using a quantitative behavioral score. A postmortem histologic analysis of the brain was carried out on all animals. RESULTS: The rate of mortality was 2 of 10 in the leukocyte-depletion group and 5 of 10 in control animals. The risk for early death in control animals was 2.5 (95% confidence interval, 0.63-10.0) times higher than that of the leukocyte-depleted animals. The median behavioral score at day 7 was higher in the leukocyte-depletion group (8.5 vs 3.5; P =.04). The median of total histopathologic score was 8.5 in the leukocyte-depletion group and 15.5 in the control group (P =.005). CONCLUSION: A leukocyte-depleting filter improves brain protection after a prolonged period of hypothermic circulatory arrest.

Serum S-100beta protein predicts brain injury after hypothermic circulatory arrest in pigs.

OBJECTIVE: Serum S-100beta protein is suggested to be a neurobiochemical marker of brain injury after cardiac and aortic arch surgery. The aim of the present study was to investigate the predictive value of S-100beta protein with respect to histopathological analysis of the brain after a prolonged period of hypothermic circulatory arrest (HCA). METHODS: Eighteen pigs (21 to 31 kg) underwent a 75 min period of HCA at 20 degrees C. Serum concentrations of S-100beta were assayed in mixed venous blood before and 2, 4, 7 and 20 h after HCA. A semiquantitative post-mortem histopathological analysis scoring all main regions of the brain was carried out in every animal. RESULTS: All animals were stable during and after cardiopulmonary bypass (CPB) and survived at least to the first postoperative day. Ten of the 18 animals survived 7 days after surgery and were electively sacrificed. Animals with severe histopathological injury showed higher serum S-100beta protein levels at every time point after HCA. The strongest correlation between the total histopathologic score and serum S-100beta levels was found at 7 h after HCA (tau = 0.422 and p = 0.023). CONCLUSION: Serum S-100beta protein levels correlate with histopathological injury after a prolonged period of HCA in pigs. This finding supports the results of previous studies suggesting the potential accuracy of S-100beta in the prediction of brain injury after cardiac surgery.

Reversibility of allograft arteriosclerosis after retransplantation to donor strain.

The rat aortic transplant model was modified to investigate whether the vascular wall changes on chronic rejection are reversible. DA (RT1a) aortas were first transplanted to WF (RT1a) recipients. The first transplantation was accompanied, as described earlier, by an increase in intimal cellularity and thickness and typical arteriosclerotic changes of chronic rejection in the allograft intima. A second transplantation was made to DA, WF or to (DAxWF)F1 recipients 10 days-2 months after the first transplantation. In all retransplantations performed at any one of the indicated timepoints, the thickness and number of nuclei of the intima continued to increase. These observations demonstrate that, after an initial trigger, allograft arteriosclerosis proceeds and is irreversible despite elimination of histoincompatibility.

Hyperlipidemia accelerates allograft arteriosclerosis (chronic rejection) in the rat.

The relevance of hyperlipidemia in allograft arteriosclerosis (chronic rejection) is controversial. Isolated hypercholesterolemia induced with cholesterol-cholic acid-diet (CC-diet) or hypertriglyceridemia induced with glycerol-diet (G-diet) had no or only a protective effect on aortic allograft arteriosclerosis in the rat. Combined hyperlipidemia with both diets (CC+G-diet) enhanced allograft arteriosclerosis by doubling intimal thickness and cellularity (P < .05) but had no effect on host arteries. Compared with normolipidemic controls, the CC+G-diet increased the total serum cholesterol concentration 4.8-fold (P < .05). Levels of VLDL2 and IDL increased 4.8- and 18.1-fold (P < .05), and their composition changed from triglyceride-rich to cholesterol-rich lipoproteins in an atherogenic direction. The CC+G-diet had no effect on the structure of inflammation in the vascular wall. Instead, significant lipid deposits were observed, and the expression of epidermal growth factor and insulin-like growth factor-1 was significantly elevated in the vascular wall. Thus, elevations in VLDL and IDL lipoprotein levels and their cholesterol content associate with the generation of allograft arteriosclerosis in rats. Deposition of lipids in the vascular wall seems to induce local synthesis of certain growth factors, which ultimately leads to the induction of smooth muscle cell replication.

Sialyl Lewis(x)- and L-selectin-dependent site-specific lymphocyte extravasation into renal transplants during acute rejection.

Kidney allograft rejection is an inflammatory process dominated by lymphocytes. During rejection lymphocytes preferentially adhere to the peritubular capillary endothelium (PTCE), which acquires morphological features common to high endothelium. These observations indicate that PTCE is the site of lymphocyte entry into the rejecting renal allograft. Of the identified endothelial adhesion molecules, ICAM-1 was already expressed on the endothelium of normal kidneys, and its expression was strongly enhanced during rejection without site-specific restriction. VCAM-1 was not expressed on the endothelium of normal or syngeneic kidneys, but its expression was induced during allograft rejection not only in PTCE, but occasionally also on the endothelium of larger vessels. Sialyl Lewisx (sLex) showed a very restricted pattern of expression; endothelium was sLex-negative both in control and syngeneic kidneys. On the other hand, PTCE reacted strongly with anti-sLex antibody in allografts. When kidney frozen sections were treated with sialidase the binding of lymphocytes decreased by 70%. Low-dose chymotrypsin treatment of lymphocytes, known to remove L-selectin from the lymphocyte surface, decreased their binding to PTCE by 60%. Likewise lymphocyte adhesion to PTCE was inhibited by 70% by anti-sLex- and anti-L-selectin-antibodies and by sLex tetrasaccharide. Finally PTCE in the allografts, but not in syngeneic grafts or normal kidneys, bound an L-selectin-IgG fusion protein, indicating that ligands for L-selectin were induced during rejection.

Somatostatin analog lanreotide inhibits myocyte replication and several growth factors in allograft arteriosclerosis.

Chronic rejection is the most common reason for late loss of a transplant. The molecular mechanism of chronic rejection is not known and there is no treatment for this disorder. The characteristic histological feature in chronic rejection is increased smooth muscle cell replication in the vascular wall, leading to allograft arteriosclerosis. In this study we demonstrate that nonimmunosuppressed rat aortic allografts undergoing chronic rejection synthesize increased quantities of several smooth muscle cell growth-promoting substances in the vascular wall including interleukin-1, eicosanoids, and several peptide growth factors. Administration of a stable somatostatin analog lanreotide, BIM 23014, strongly inhibits myocyte proliferation in the allograft in vivo. It has no inhibitory effect on the proliferation of smooth muscle cells in vitro. Concomitantly, the locally produced peptide growth factors, i.e., epidermal growth factor, insulin-like growth factor 1, and BB-isomer of platelet-derived growth factor, but not other mediators of inflammation, are significantly reduced. The results suggest that growth factors are the main effector molecules leading to myocyte proliferation in allograft arteriosclerosis and that allograft arteriosclerosis (chronic rejection) may be specifically inhibited by lanreotide administration.

Intimal thickening and medial necrosis in allograft arteriosclerosis (chronic rejection) are independently regulated.

Rat aortic allografts from the DA (RT1a) to the WF (RT1v) strain but not syngeneic DA-to-DA control grafts develop arteriosclerotic changes in the vascular wall that are virtually identical to human allografts during chronic rejection. A more prominent medial cell destruction in the rat aorta, leading ultimately to complete medial necrosis, is the major difference between rat and human allografts. If the adventitia of syngeneic grafts is exposed to starch before transplantation, these grafts also develop an inflammatory reaction in the adventitia and an extensive intimal thickening at the site of the granulomas, but the medial smooth muscle cells are preserved. In both types of transplants with an intact endothelium as determined by light microscopy, adventitial inflammatory cell proliferation was accompanied by smooth muscle cell replication in the media and thickening of the intima. We therefore propose that an adventitial proliferative response is a prerequisite for intimal thickening to occur. In the allograft but not in starch-exposed syngeneic grafts there was also a notable lymphoid activation in the adventitia, which was accompanied by medial necrosis. We suggest that the medial necrosis in the allograft is linked to a toxic effect of activated lymphoid cells on medial myocytes and is not a prerequisite for intimal proliferation. Instead, intimal proliferation and medial necrosis in the allograft seem to be independently regulated.