A porcine large animal model of radiofrequency ablation-induced left bundle branch block.

Background: Electrocardiographic (ECG) features of left bundle branch (LBB) block (LBBB) can be observed in up to 20%-30% of patients suffering from heart failure with reduced ejection fraction. However, predicting which LBBB patients will benefit from cardiac resynchronization therapy (CRT) or conduction system pacing remains challenging. This study aimed to establish a translational model of LBBB to enhance our understanding of its pathophysiology and improve therapeutic approaches. Methods: Fourteen male pigs underwent radiofrequency catheter ablation of the proximal LBB under fluoroscopy and ECG guidance. Comprehensive clinical assessments (12-lead ECG, bloodsampling, echocardiography, electroanatomical mapping) were conducted before LBBB induction, after 7, and 21 days. Three pigs received CRT pacemakers 7 days after LBB ablation to assess resynchronization feasibility. Results: Following proximal LBB ablation, ECGs displayed characteristic LBBB features, including QRS widening, slurring in left lateral leads, and QRS axis changes. QRS duration increased from 64.2 ± 4.2 ms to 86.6 ± 12.1 ms, and R wave peak time in V6 extended from 21.3 ± 3.6 ms to 45.7 ± 12.6 ms. Echocardiography confirmed cardiac electromechanical dyssynchrony, with septal flash appearance, prolonged septal-to-posterior-wall motion delay, and extended ventricular electromechanical delays. Electroanatomical mapping revealed a left ventricular breakthrough site shift and significantly prolonged left ventricular activation times. RF-induced LBBB persisted for 3 weeks. CRT reduced QRS duration to 75.9 ± 8.6 ms, demonstrating successful resynchronization. Conclusion: This porcine model accurately replicates the electrical and electromechanical characteristics of LBBB observed in patients. It provides a practical, cost-effective, and reproducible platform to investigate molecular and translational aspects of cardiac electromechanical dyssynchrony in a controlled and clinically relevant setting.

Regnase-1 overexpression as a therapeutic approach of Marfan syndrome.

Rupture or dissection of thoracic aortic aneurysms is still the leading cause of death for patients diagnosed with Marfan syndrome. Inflammation and matrix digestion regulated by matrix metalloproteases (MMPs) play a major role in the pathological remodeling of the aortic media. Regnase-1 is an endoribonuclease shown to cleave the mRNA of proinflammatory cytokines, such as interleukin-6. Considering the major anti-inflammatory effects of regnase-1, here, we aimed to determine whether adeno-associated virus (AAV)-mediated vascular overexpression of the protein could provide protection from the development and progression of aortic aneurysms in Marfan syndrome. The overexpression of regnase-1 resulted in a marked decrease in inflammatory parameters and elastin degradation in aortic smooth muscle cells in vitro. Intravenous injection of a vascular-targeted AAV vector resulted in the efficient transduction of the aortic wall and overexpression of regnase-1 in a murine model of Marfan syndrome, associated with lower circulating levels of proinflammatory cytokines and decreased MMP expression and activity. Regnase-1 overexpression strongly improved elastin architecture in the media and reduced aortic diameter at distinct locations. Therefore, AAV-mediated regnase-1 overexpression may represent a novel gene therapy approach for inhibiting aortic aneurysms in Marfan syndrome.

Analysing and improving preoperative medication management in cardiac surgery.

AIMS: The objective of this study was to analyse the preoperative medication management within the cardiac surgery patient population and measure the effectiveness of an interprofessional intervention in routine care. METHODS: A jointly developed preoperative medication management was implemented in routine care on multiple levels (inclusion in admission letter to primary care, hotline for inquiries, pocket cards for physicians and correspondence with referring centres). The effectiveness was evaluated by analysing preoperative management before and after implementation. The primary endpoint was the number of drugs managed correctly according to the guidelines after implementation. Secondary endpoints consisted amongst others of bleeding on the intensive care unit, re-thoracotomy, postoperative infarction and cerebrovascular complications. Additionally, possible associations between the correct management and different variables were investigated by multivariate analysis. RESULTS: After the implementation, the number of drugs managed correctly according to guidelines increased from 54.0 to 73.5% (P < .001). The effect was more prominent for direct oral anticoagulants and prophylactic aspirin where the guideline adherence increased from 29.2 to 74.5% and from 78.6 to 95.1%, respectively. No difference was seen for sodium-glucose transporter-2 inhibitors, metformin, vitamin-K antagonists and dual-antiplatelet therapy. Secondary endpoints showed no safety signals with regard to bleeding or thrombotic events. In multivariate analysis, the intervention was effective (odds ratio 2.17, 95% confidence interval [1.32-3.62]) after adjusting for possible confounders. CONCLUSION: An interprofessional programme was effective to improve preoperative medication management in cardiac surgery patients. Sodium-glucose transporter-2 inhibitors, metformin and direct oral anticoagulants appear to be especially at risk for incorrect management before cardiac surgery with possible adverse events.

Cavoatrial hypernephroma resection on cardiopulmonary bypass: Mild/normo-versus moderate hypothermia.

INTRODUCION: Renal cell carcinoma (RCC) is one of the most prevalent malignant tumors. It extends up into the systemic veins and right atrium. Surgical extraction of such extensions is usually carried out using cardiopulmonary bypass (CPB) with moderate hypothermic (MH) being frequently applied in order to obtain a clear surgical field. However, due to obvious disadvantages of hypothermia, approaches with mild/normothermia (NT) during CPB have also been established. The current study aims to compare the outcomes of patients undergoing RCC tumor and extensions resection using MH versus NT. MATERIAL AND METHODS: This is a retrospective, non-randomized study. All patients who underwent RCC tumor and extensions resection for stage III or IV (Staehler) RCC in a single center between 2006 and 2020 were included. During surgery, MH or NT were applied. CPB was realized using aortic and bicaval cannulation. We compared the procedural times, transfusion requirements and postoperative outcomes, respectively between the MH and NT groups. RESULTS: A total of 24 consecutive patients (n(NT) = 12, n(MH) = 12) were included in the study (median age NT 68.5 and MH 66.5). The study only showed a significant difference in heart-lung machine times (median CPB time NT 45.5 min and MH 110.0 min, p = 0.004). All other results, loss of drainage, administration of blood products, as well as the postoperative course and mortality were comparable in both groups. CONCLUSION: The results showed a high perioperative and long-term mortality. The perioperative course was similar after surgery with NT or MH. Therefore, NT which minimizes potential complications of MH should be preferred.

Effects of Rapamycin on the Expression of Redox Enzymes in Aortic Vascular Smooth Muscle Cells from Marfan Syndrome Mice.

Activation of the mechanistic target of rapamycin (mTOR) pathway has been implicated in an increasing number of diseases, including Marfan syndrome (MFS), an inherited connective tissue disorder. mTOR-dependent reactive oxygen species (ROS) formation has also been suggested to play a role in aortic aneurysm formation in MFS patients. This study aimed to characterize the effects of mTOR inhibition by rapamycin on key redox enzymes and NADPH oxidases (NOX) in cultured vascular smooth muscle cells of a murine MFS model. Therefore, the influence of 5 and 20 nmol/L rapamycin solved in 0.1% (vol/vol) DMSO on glutathione peroxidases 1 (Gpx1) and 4 (Gpx4), superoxide dismutase 2 (Sod2), and catalase (Cat) mRNA and protein expression was investigated in isolated murine aortic smooth muscle cells. Rapamycin inhibited the mRNA expression of all redox enzymes by 30-50%, except Gpx1. In the same cells, the mRNA expression of the transcription factor NFE2-related factor-2 and peroxisome proliferator-activated receptor-γ, key factors against oxidative stress, and controlling redox gene expression were also inhibited to a comparable extent under these conditions. In addition, Nox1 but not Nox4 mRNA expression was significantly inhibited by up to 40%. DMSO alone increased nearly 2-fold the redox enzyme protein expression, which was reduced considerably to basal levels by rapamycin. Proteasomal inhibition by bortezomib could not reverse the observed decrease of GPx protein content. The rapamycin-mediated decrease in GPx protein abundance was reflected in a reduced total GPx enzymatic activity. Higher rapamycin concentrations did not further decrease but led to a renewed increase in enzymatic activity despite low GPx protein concentrations. Baseline ROS formation was slightly inhibited at 13% with 5 nmol/L rapamycin and returned to baseline levels with the higher 20 nmol/L rapamycin concentration. In conclusion, this study further characterized the mechanism of action of rapamycin. It provided an insight into how rapamycin interferes with the regulation of redox homeostasis essential for ROS-dependent signaling that does not incur cellular damage.

Translational Medicine: Towards Gene Therapy of Marfan Syndrome.

Marfan syndrome (MFS) is one of the most common inherited disorders of connective tissue caused by mutations of the fibrillin-1 gene (FBN1). Vascular abnormalities, such as the enlargement of the aorta with the risk of life-threatening rupture are frequently observed. However, current treatment is limited and therapeutic options focus solely on symptomatic therapy. Gene therapy focuses on genetically modifying cells to produce a therapeutic effect and may be a promising treatment option for MFS. Here, we first provide an overview of the historical background and characterization of MFS. Subsequently, we summarise current gene therapy options and possible translational concepts for this inherited disorder that affects connective tissue.

Renal Safety of Hydroxyethyl starch 130/0.42 After Cardiac Surgery: A Retrospective Cohort Analysis.

INTRODUCTION: The risk for renal complications from hydroxyethyl starch 130/0.42 (HES) impacts treatment decisions in patients after cardiac surgery. OBJECTIVE: The objective of this study was to determine the impact of postoperatively administered HES on renal function and 90-day mortality compared to sole crystalloid administration in patients after elective cardiac surgery. METHODS: Using electronic health records from a university hospital, confounding-adjusted models analyzed the associations between postoperative HES administration and the occurrence of postoperative acute kidney injury. In addition, 90-day mortality was evaluated. The impact of HES dosage and timing on renal function on trajectories of estimated glomerular filtration rates over the postoperative period was investigated using linear mixed-effects models. RESULTS: Overall 1009 patients (45.0%) experienced acute kidney injury. Less acute kidney injury occurred in patients receiving HES compared with patients receiving only crystalloids for fluid resuscitation (43.7% vs 51.2%, p = 0.008). In multivariate acute kidney injury models, HES had a protective association (odds ratio: 0.89; 95% confidence interval 0.82-0.96). Crystalloids were not as protective as HES (odds ratio: 0.98; 95% confidence interval 0.95-1.00). There was no association between HES and 90-day mortality (odds ratio: 1.05; 95% confidence interval 0.88-1.25). Renal function trajectories were dose dependent and biphasic, HES appeared to slow down the late postoperative decline. CONCLUSIONS: This study showed no association between HES and the postoperative occurrence of acute kidney injury and thus further closes the evidence gap on HES safety in cardiac surgery patients. Although this was a retrospective cohort study, the results indicated that HES might be safely administered to cardiac surgery patients with regard to renal outcomes, especially if it was administered early and dosed appropriately.

Alginate hydrogel polymers enable efficient delivery of a vascular-targeted AAV vector into aortic tissue.

Gene therapeutic approaches to aortic diseases require efficient vectors and delivery systems for transduction of endothelial cells (ECs) and smooth muscle cells (SMCs). Here, we developed a novel strategy to efficiently deliver a previously described vascular-specific adeno-associated viral (AAV) vector to the abdominal aorta by application of alginate hydrogels. To efficiently transduce ECs and SMCs, we used AAV9 vectors with a modified capsid (AAV9SLR) encoding enhanced green fluorescent protein (EGFP), as wild-type AAV vectors do not transduce ECs and SMCs well. AAV9SLR vectors were embedded into a solution containing sodium alginate and polymerized into hydrogels. Gels were surgically implanted around the adventitia of the infrarenal abdominal aorta of adult mice. Three weeks after surgery, an almost complete transduction of both the endothelium and tunica media adjacent to the gel was demonstrated in tissue sections. Hydrogel-mediated delivery resulted in induction of neutralizing antibodies but did not cause inflammatory responses in serum or the aortic wall. To further determine the translational potential, aortic tissue from patients was embedded ex vivo into AAV9SLR-containing hydrogel, and efficient transduction could be confirmed. These findings demonstrate that alginate hydrogel harboring a vascular-targeting AAV9SLR vector allows efficient local transduction of the aortic wall.

AAV-mediated AP-1 decoy oligonucleotide expression inhibits aortic elastolysis in a mouse model of Marfan syndrome.

AIMS: Marfan syndrome is one of the most common inherited disorders of connective tissue caused by fibrillin-1 mutations, characterized by enhanced transcription factor AP-1 DNA binding activity and subsequently abnormally increased expression and activity of matrix-metalloproteinases (MMPs). We aimed to establish a novel adeno-associated virus (AAV)-based strategy for long-term expression of an AP-1 neutralizing RNA hairpin (hp) decoy oligonucleotide (dON) in the aorta to prevent aortic elastolysis in a murine model of Marfan syndrome. METHODS AND RESULTS: Using fibrillin-1 hypomorphic mice (mgR/mgR), aortic grafts from young (9 weeks old) donor mgR/mgR mice were transduced ex vivo with AAV vectors and implanted as infrarenal aortic interposition grafts in mgR/mgR mice. Grafts were explanted after 30 days. For in vitro studies, isolated primary aortic smooth muscle cells (SMCs) from mgR/mgR mice were used. Elastica-van-Giesson staining visualized elastolysis, reactive oxygen species (ROS) production was assessed using dihydroethidine staining. RNA F.I.S.H. verified AP-1 hp dON generation in the ex vivo transduced aortic tissue. MMP expression and activity were assessed by western blotting and immunoprecipitation combined with zymography.Transduction resulted in stable therapeutic dON expression in endothelial and SMCs. MMP expression and activity, ROS formation as well as expression of monocyte chemoattractant protein-1 were significantly reduced. Monocyte graft infiltration declined and the integrity of the elastin architecture was maintained. RNAseq analysis confirmed the beneficial effect of AP-1 neutralization on the pro-inflammatory environment in SMCs. CONCLUSION: This novel approach protects from deterioration of aortic stability by sustained delivery of nucleic acids-based therapeutics and further elucidated how to interfere with the mechanism of elastolysis.

Vascular Signaling in Allogenic Solid Organ Transplantation - The Role of Endothelial Cells.

Graft rejection remains the major obstacle after vascularized solid organ transplantation. Endothelial cells, which form the interface between the transplanted graft and the host's immunity, are the first target for host immune cells. During acute cellular rejection endothelial cells are directly attacked by HLA I and II-recognizing NK cells, macrophages, and T cells, and activation of the complement system leads to endothelial cell lysis. The established forms of immunosuppressive therapy provide effective treatment options, but the treatment of chronic rejection of solid organs remains challenging. Chronic rejection is mainly based on production of donor-specific antibodies that induce endothelial cell activation-a condition which phenotypically resembles chronic inflammation. Activated endothelial cells produce chemokines, and expression of adhesion molecules increases. Due to this pro-inflammatory microenvironment, leukocytes are recruited and transmigrate from the bloodstream across the endothelial monolayer into the vessel wall. This mononuclear infiltrate is a hallmark of transplant vasculopathy. Furthermore, expression profiles of different cytokines serve as clinical markers for the patient's outcome. Besides their effects on immune cells, activated endothelial cells support the migration and proliferation of vascular smooth muscle cells. In turn, muscle cell recruitment leads to neointima formation followed by reduction in organ perfusion and eventually results in tissue injury. Activation of endothelial cells involves antibody ligation to the surface of endothelial cells. Subsequently, intracellular signaling pathways are initiated. These signaling cascades may serve as targets to prevent or treat adverse effects in antibody-activated endothelial cells. Preventive or therapeutic strategies for chronic rejection can be investigated in sophisticated mouse models of transplant vasculopathy, mimicking interactions between immune cells and endothelium.

AAV-mediated TIMP-1 overexpression in aortic tissue reduces the severity of allograft vasculopathy in mice.

BACKGROUND: Allograft vasculopathy (AV) is the primary limiting factor for long-term graft survival. An increased activity of matrix metalloproteinases (MMPs) contributes to neointima formation in AV and represents a potential therapeutic target. Adeno-associated virus (AAV)-mediated gene therapy comprises a potentially benign vector model for the long-term expression of MMP antagonists. METHODS: Aortic allografts from DBA/2 mice were incubated with control buffer, AAV-enhanced green fluorescence protein (EGFP), or tissue inhibitor of metalloproteinases 1 (TIMP-1)-loaded AAV (AAV-TIMP-1) and transplanted into the infrarenal aorta of C57BL/6 mice. Cyclosporine A (10 mg/kg body weight) was administered daily. Explantation as well as histomorphometric and immunohistochemical evaluation was performed after 30 days. Matrix metalloproteinase (MMP) activity was visualized by gelatin in situ zymography. RESULTS: Intima-to-media area ratio and neointima formation were significantly reduced in the AAV-TIMP-1 treatment group compared with those in the control group (by 40%; p < 0.001) and the AAV-EGFP group (by 38.2%; p < 0.001). TIMP-1 overexpression positively affected several pathomechanisms for the development of AV both in vitro and in vivo as compared to that in the control groups: endothelium integrity was preserved as shown by zona occludens 1 and occludin staining; MMP9 expression and activity were significantly reduced (p = 0.01); and smooth muscle cell migration was significantly reduced as smooth muscle actin positive cells predominantly remained in the aortic media in the treatment group (p = 0.001). Moreover, macrophage infiltration was markedly reduced by 49% in the AAV-TIMP-1 group (p < 0.001). CONCLUSION: Immediate post-harvesting allograft incubation with AAV-TIMP-1 reduces neointima formation and macrophage infiltration, constituting a possible adjunct therapeutic strategy to preserve graft function after transplantation.

The reimplantation valve-sparing aortic root replacement technique for patients with Marfan syndrome: A single-center experience.

Valve-sparing aortic root replacement (VSARR) through reimplantation technique is widely regarded as optimal surgical approach for Marfan syndrome (MFS) patients. Perioperative and long-term data from all MFS patients undergoing VSARR using David's technique at our center from 2007-2018 were analyzed. We included 56 patients with a mean age of 32.3 ± 12.3 years. Logistic EuroSCORE was 7.96 ± 5.2. Among others concomitant surgical procedures included aortic arch surgery (8.9%), mitral valve repair (23.2%) and replacement (1.7%). There were no operative deaths, nor in-hospital-mortality. One patient underwent re-exploration for bleeding, dialysis and pacemaker implantation was required in one case each. There was no occurrence of low-output syndrome nor neurological complications. Significant gender differences were not found, except for intraoperative blood transfusion occurring significantly more often in the female gender (p = 0.009). Despite significantly longer procedural times, concomitant surgery did not negatively impact overall outcome. Freedom of reoperation of the aortic root was 100% at 1 year, 97.7% at 8 years. Until last follow-up (61 ± 38 month) all patients survived, with no evidence of endocarditis. We emphasize once more that VSARR using David's procedure is a safe method for MFS patients with excellent long-term results even if concomitant procedures are performed.

An integrative systems approach identifies novel candidates in Marfan syndrome-related pathophysiology.

Marfan syndrome (MFS) is an autosomal dominant genetic disorder caused by mutations in the FBN1 gene. Although many peripheral tissues are affected, aortic complications, such as dilation, dissection and rupture, are the leading causes of MFS-related mortality. Aberrant TGF-beta signalling plays a major role in the pathophysiology of MFS. However, the contributing mechanisms are still poorly understood. Here, we aimed at identifying novel aorta-specific pathways involved in the pathophysiology of MFS. For this purpose, we employed the Fbn1 under-expressing mgR/mgR mouse model of MFS. We performed RNA-sequencing of aortic tissues of 9-week-old mgR/mgR mice compared with wild-type (WT) mice. With a false discovery rate <5%, our analysis revealed 248 genes to be differentially regulated including 20 genes previously unrelated with MFS-related pathology. Among these, we identified Igfbp2, Ccl8, Spp1, Mylk2, Mfap4, Dsp and H19. We confirmed the expression of regulated genes by quantitative real-time PCR. Pathway classification revealed transcript signatures involved in chemokine signalling, cardiac muscle contraction, dilated and hypertrophic cardiomyopathy. Furthermore, our immunoblot analysis of aortic tissues revealed altered regulation of pSmad2 signalling, Perk1/2, Igfbp2, Mfap4, Ccl8 and Mylk2 protein levels in mgR/mgR vs WT mice. Together, our integrative systems approach identified several novel factors associated with MFS-aortic-specific pathophysiology that might offer potential novel therapeutic targets for MFS.

Reduction of Transplant Vasculopathy by Intraoperative Nucleic Acid-based Therapy in a Mouse Aortic Allograft Model.

BACKGROUND: Transplant vasculopathy (TV) is the main limiting factor for long-term graft survival characterized by fibrosis, myofibroblast, and smooth muscle cell (SMC) proliferation. Decoy oligodeoxynucleotide (dODN) against the transcription factor activator protein-1 (AP-1) might interfere with the expression of AV-related genes that govern neointima formation. METHODS: Aortic allografts from DBA/2 mice were incubated with control buffer, consensus, or mutated control AP-1 dODN and were transplanted into the infrarenal aorta of C57BL/6 mice. Cyclosporine A (10 mg/kg body weight [BW]) was administered daily. Explantation and histomorphometric and immunohistochemical evaluation was performed after 30 days. Matrix metalloproteinase (MMP) activity was visualized by gelatin in situ zymography. RESULTS: Intima-to-media (I/M) ratio and neointima formation were significantly reduced in the consensus AP-1 dODN treatment group by 37% (p < 0.05) and 67% (p < 0.01), respectively. SMC α-actin-2 staining and macrophage marker expression revealed a marked reduction in the neointima. I/M ratio was found to correlate with the number of tissue macrophages (p < 0.05). MMP and fibrosis marker expression were not significantly altered. CONCLUSION: Intraoperative AP-1dODN utilization might be a strategy to preserve graft function after transplantation.

AP-1 Oligodeoxynucleotides Reduce Aortic Elastolysis in a Murine Model of Marfan Syndrome.

Marfan syndrome is characterized by high expression of matrix metalloproteinases (MMPs) in aortic smooth muscle cells (AoSMCs) associated with medial elastolysis and aortic root aneurysm. We aimed to reduce aortic elastolysis through decrease of MMP expression with decoy oligodeoxynucleotides (dODNs) neutralizing the transcription factor activating factor-1 (AP-1). AP-1 abundance in nuclear extracts as well as MMP-2 and MMP-9 expression were significantly increased in isolated mAoSMC of mgR/mgR Marfan mice compared to wild-type cells. Exposure to AP-1 neutralizing dODNs resulted in a significant reduction of basal and interleukin-1ß-stimulated MMP expression and activity in mAoSMCs. Moreover, increased migration and formation of superoxide radical anions was substantially decreased in mAoSMCs by AP-1 dODN treatment. Aortic grafts from donor Marfan mice were treated with AP-1- dODN ex vivo and implanted as infrarenal aortic interposition grafts in mgR/mgR mice. Pretreatment of aortic grafts with AP-1 dODN led to reduced elastolysis, macrophage infiltration, and MMP activity. Permeability of the endothelial monolayer was increased for dODN in mgR/mgR aortae with observed loss of tight junction proteins ZO-1 and occludin, enabling dODN to reach the tunica media. Targeting AP-1 activity offers a new potential strategy to treat the vascular phenotype associated with Marfan syndrome.

Ischemic Colitis after Cardiac Surgery: Can We Foresee the Threat?

INTRODUCTION: Ischemic colitis (IC) remains a great threat after cardiac surgery with use of extracorporeal circulation. We aimed to identify predictive risk factors and influence of early catecholamine therapy for this disease. METHODS: We prospectively collected and analyzed data of 224 patients, who underwent laparotomy due to IC after initial cardiac surgery with use of extracorporeal circulation during 2002 and 2014. For further comparability 58 patients were identified, who underwent bypass surgery, aortic valve replacement or combination of both. Age ±5 years, sex, BMI ± 5, left ventricular function, peripheral arterial disease, diabetes and urgency status were used for match-pair analysis (1:1) to compare outcome and detect predictive risk factors. Highest catecholamine doses during 1 POD were compared for possible predictive potential. RESULTS: Patients' baseline characteristics showed no significant differences. In-hospital mortality of the IC group with a mean age of 71 years (14% female) was significantly higher than the control group with a mean age of 70 (14% female) (67% vs. 16%, p<0.001). Despite significantly longer bypass time in the IC group (133 ± 68 vs. 101 ± 42, p = 0.003), cross-clamp time remained comparable (64 ± 33 vs. 56 ± 25 p = 0.150). The majority of the IC group suffered low-output syndrome (71% vs. 14%, p<0.001) leading to significant higher lactate values within first 24h after operation (55 ± 46 mg/dl vs. 31 ± 30 mg/dl, p = 0.002). Logistic regression revealed elevated lactate values to be significant predictor for colectomy during the postoperative course (HR 1.008, CI 95% 1.003-1.014, p = 0.003). However, Receiver Operating Characteristic Curve calculates a cut-off value for lactate of 22.5 mg/dl (sensitivity 73% and specificity 57%). Furthermore, multivariate analysis showed low-output syndrome (HR 4.301, CI 95% 2.108-8.776, p<0.001) and vasopressin therapy (HR 1.108, CI 95% 1.012-1.213, p = 0.027) significantly influencing necessity of laparotomy. CONCLUSION: Patients who undergo laparotomy for IC after initial cardiac surgery have a substantial in-hospital mortality risk. Early postoperative catecholamine levels do not influence the development of an IC except vasopressin. Elevated lactate remains merely a vague predictive risk factor.

Loss of Endothelial Barrier in Marfan Mice (mgR/mgR) Results in Severe Inflammation after Adenoviral Gene Therapy.

OBJECTIVES: Marfan syndrome is an autosomal dominant inherited disorder of connective tissue. The vascular complications of Marfan syndrome have the biggest impact on life expectancy. The aorta of Marfan patients reveals degradation of elastin layers caused by increased proteolytic activity of matrix metalloproteinases (MMPs). In this study we performed adenoviral gene transfer of human tissue inhibitor of matrix metalloproteinases-1 (hTIMP-1) in aortic grafts of fibrillin-1 deficient Marfan mice (mgR/mgR) in order to reduce elastolysis. METHODS: We performed heterotopic infrarenal transplantation of the thoracic aorta in female mice (n = 7 per group). Before implantation, mgR/mgR and wild-type aortas (WT, C57BL/6) were transduced ex vivo with an adenoviral vector coding for human TIMP-1 (Ad.hTIMP-1) or ß-galactosidase (Ad.ß-Gal). As control mgR/mgR and wild-type aortas received no gene therapy. Thirty days after surgery, overexpression of the transgene was assessed by immunohistochemistry (IHC) and collagen in situ zymography. Histologic staining was performed to investigate inflammation, the neointimal index (NI), and elastin breaks. Endothelial barrier function of native not virus-exposed aortas was evaluated by perfusion of fluorescent albumin and examinations of virus-exposed tissue were performed by transmission electron microscopy (TEM). RESULTS: IHC and ISZ revealed sufficient expression of the transgene. Severe cellular inflammation and intima hyperplasia were seen only in adenovirus treated mgR/mgR aortas (Ad.ß-Gal, Ad.hTIMP-1 NI: 0.23; 0.43), but not in native and Ad.hTIMP-1 treated WT (NI: 0.01; 0.00). Compared to native mgR/mgR and Ad.hTIMP-1 treated WT aorta, the NI is highly significant greater in Ad.hTIMP-1 transduced mgR/mgR aorta (p = 0.001; p = 0.001). As expected, untreated Marfan grafts showed significant more elastolysis compared to WT (p = 0.001). However, elastolysis in Marfan aortas was not reduced by adenoviral overexpression of hTIMP-1 (compared to untreated Marfan aorta: Ad.hTIMP-1 p = 0.902; control Ad.ß-Gal. p = 0.165). The virus-untreated and not transplanted mgR/mgR aorta revealed a significant increase of albumin diffusion through the endothelial barrier (p = 0.037). TEM analysis of adenovirus-exposed mgR/mgR aortas displayed disruption of the basement membrane and basolateral space. CONCLUSIONS: Murine Marfan aortic grafts developed severe inflammation after adenoviral contact. We demonstrated that fibrillin-1 deficiency is associated with relevant dysfunction of the endothelial barrier that enables adenovirus to induce vessel-harming inflammation. Endothelial dysfunction may play a pivotal role in the development of the vascular phenotype of Marfan syndrome.