Inhibition of Vascular Endothelial Growth Factor Receptors 1 and 2 Attenuates Natural Killer Cell and Innate Immune Responses in an Experimental Model for Obliterative Bronchiolitis.

Obliterative bronchiolitis (OB) after lung transplantation is a nonreversible, life-threatening complication. Herein, the role of vascular endothelial growth factor receptor (Vegfr)-1 and -2 was investigated in the development of obliterative airway disease (OAD), an experimental model for OB. The nonimmunosuppressed recipients underwent transplantation with fully major histocompatibility complex mismatched heterotopic tracheal allografts and received Vegfr1 and -2-specific monoclonal antibodies either alone or in combination, or rat IgG as a control. The treatment with Vegfr1- or -2-blocking antibody significantly decreased intragraft mRNA expression of natural killer cell activation markers early after transplantation. This was followed by reduced infiltration of Cd11b+ cells and Cd4+ T cells as well as down-regulated mRNA expression of proinflammatory chemokines and profibrotic growth factors. However, blocking of both Vegfr1 and -2 was necessary to reduce luminal occlusion. Furthermore, concomitant inhibition of the calcineurin activation pathway almost totally abolished the development of OAD. This study proposes that blocking of Vegf receptors blunted natural killer cell and innate immune responses early after transplantation and attenuated the development of OAD. The results of this study suggest that further studies on the role of Vegfr1 and -2 blocking in development of obliterative airway lesions might be rewarding.

Cancer risk and mortality after solid organ transplantation: A population-based 30-year cohort study in Finland.

Cancer is a significant cause of morbidity and mortality after solid organ transplantation (SOT) and related to lifelong immunosuppression. This retrospective registry study assessed for the first time in Finland population-based cancer risk and cancer mortality after all SOTs (lung and childhood transplantations included) as standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs). Data from transplant registries were linked with the data of Finnish Cancer Registry and Statistics Finland. We followed 6548 consecutive first SOT recipients from 1 January 1987 to 31 December 2016 translating to 66 741 person-years (median follow-up time 8.9 years [interquartile range 4.0-15.1]). In total, 2096 cancers were found in 1483 patients (23% of all patients). Majority of cancers (53%) were nonmelanoma skin cancers (NMSCs). The overall SIR was 3.6 (95% confidence interval [CI]: 3.5-3.8) and the SIR excluding NMSCs was 2.2 (95% CI: 2.0-2.3). SIR for all cancers was highest for heart (5.0) and lowest for liver (2.7) recipients. Most common cancer types after NMSCs were non-Hodgkin lymphoma (NHL), SIR 9.9 (95% CI: 8.5-11.4) and kidney cancer, SIR 7.3 (95% CI: 6.0-8.8). Cancer-related deaths were 17% (n = 408) of all deaths after first month post transplantation. SMR for all cancers was 2.5 (95% CI: 2.2-2.7) and for NHL 13.6 (95% CI: 10.7-16.8). Notably, overall SIR for cancer was lower in later period (2000-2016), 3.0 (95% CI: 2.8-3.2), than in earlier period (1987-1999), 4.3 (95% CI: 4.0-4.5), P < .001. Decrease in cancer incidence was temporally associated with major changes in immunosuppression in the 2000s.

Donor Simvastatin Treatment in Heart Transplantation.

BACKGROUND: Ischemia-reperfusion injury may compromise the short-term and long-term prognosis after heart transplantation. Experimental studies show that simvastatin administered to the organ donor is vasculoprotective and inhibits cardiac allograft ischemia-reperfusion injury. METHODS: Eighty-four multiorgan donors were randomly assigned to receive 80 mg of simvastatin (42 donors) via nasogastric tube after declaration of brain death and upon acceptance as a cardiac donor, or to receive no simvastatin (42 donors). The primary efficacy end point was postoperative plasma troponin T and I levels during the first 24 hours after heart transplantation. Secondary end points included postoperative hemodynamics, inflammation, allograft function, rejections and rejection treatments, and mortality. Results: Organ donor simvastatin treatment significantly reduced the heart recipient plasma levels of troponin T by 34% (14 900 ± 12 100 ng/L to 9800 ± 7900 ng/L, P=0.047), and troponin I by 40% (171 000 ± 151 000 ng/L to 103 000 ± 109 000 ng/L, P=0.023) at 6 hours after reperfusion, the levels of NT-proBNP (N-terminal pro-B-type natriuretic peptide) by 36% (32 800 ± 24 300 ng/L to 20 900 ± 15 900 ng/L; P=0.011) at 1 week, and the number of rejection treatments with hemodynamic compromise by 53% within the first 30 days (P=0.046). Donor simvastatin treatment did not affect donor lipid levels but was associated with a specific transplant myocardial biopsy gene expression profile, and a decrease in recipient postoperative plasma levels of CXCL10 (C-X-C motif chemokine 10), interleukin-1α, placental growth factor, and platelet-derived growth factor-BB. Postoperative hemodynamics, biopsy-proven acute rejections, and mortality were similar. No adverse effects were seen in recipients receiving noncardiac solid organ transplants from simvastatin-treated donors. CONCLUSIONS: Donor simvastatin treatment reduces biomarkers of myocardial injury after heart transplantation, and-also considering its documented general safety profile-may be used as a novel, safe, and inexpensive adjunct therapy in multiorgan donation. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01160978.

Cholesterol lowering with EVOLocumab to prevent cardiac allograft Vasculopathy in De-novo heart transplant recipients: Design of the randomized controlled EVOLVD trial.

BACKGROUND: Cardiac allograft vasculopathy (CAV) is characterized by diffuse thickening of the arterial intima. Statins reduce the incidence of CAV, but despite the use of statins, CAV remains one of the leading causes of long-term death after heart transplant. Inhibitors of proprotein convertase subtilisin-kexin type 9 (PCSK9) substantially reduce cholesterol levels but have not been tested in heart transplant recipients. METHODS: The Cholesterol lowering with EVOLocumab to prevent cardiac allograft Vasculopathy in De-novo heart transplant recipients (EVOLVD) trial (ClinicalTrials.gov Identifier: NCT03734211) is a randomized, double-blind trial designed to test the effect of the PCSK9 inhibitor evolocumab on coronary intima thickness in heart transplant recipients. Adults who have received a cardiac transplant within the past 4-8 weeks are eligible. Exclusion criteria include an estimated glomerular filtration rate < 20 mL/min/1.73 m2 , renal replacement therapy, or contraindications to coronary angiography with intravascular ultrasound. 130 patients will be randomized (1:1) to 12-month treatment with evolocumab or matching placebo. The primary endpoint is the coronary artery intima thickness as measured by intravascular ultrasound. CONCLUSION: The EVOLVD trial is a randomized clinical trial designed to show whether treatment with the PCSK9 inhibitor evolocumab can ameliorate CAV over the first year after heart transplant.

Hypoxia-inducible factor controls immunoregulatory properties of myeloid cells in mouse cardiac allografts - an experimental study.

Hypoxia-inducible factors (HIFs) play a critical role in inflammatory properties of myeloid-derived cells. The effect of HIFs on myeloid-derived cell functions in organ transplantation remains unknown, however. We transplanted hearts into transgenic mice with myeloid cell-targeted deletions of HIF-1α or its negative regulator von Hippel-Lindau (VHL) to investigate the effects of HIF-1α inactivation or HIF pathway activation, respectively, on ischemia-reperfusion injury (IRI) and acute rejection. Deletion of VHL in myeloid cells enhanced mRNA expression of anti-inflammatory genes IDO, Arg-1, and HO-1 in vitro. In vivo, VHL-/- myeloid-derived cells of allograft recipients alleviated IRI and acute rejection, evidenced by reduced cardiomyocyte damage, decreased proinflammatory cytokine mRNA levels, and absence of inflammatory infiltrate at 5 days after transplantation. Ultimately, allograft survival was significantly prolonged. In vitro, VHL-/- myeloid-derived cells dose-dependently inhibited T-cell proliferation. Myeloid cells with HIF-1α-deletion retained proinflammatory qualities in vitro and in vivo. Deletion of VHL in myeloid cells of nonimmunosuppressed cardiac allograft recipients reduced myocardial injury and acute rejection. We suggest that HIF transcription factors induce a regulatory phenotype in myeloid-derived cells, which may be harnessed as a novel therapeutic strategy to regulate immune responses after heart transplantation.

VEGF Pathways in the Lymphatics of Healthy and Diseased Heart.

Cardiac lymphatic system is a rare focus of the modern cardiovascular research. Nevertheless, the growing body of evidence is depicting lymphatic endothelium as an important functional unit in healthy and diseased myocardium. Since the discovery of angiogenic VEGF-A in 1983 and lymphangiogenic VEGF-C in 1997, an increasing amount of knowledge has accumulated on the essential roles of VEGF ligands and receptors in physiological and pathological angiogenesis and lymphangiogenesis. Tissue adaptation to several stimuli such as hypoxia, pathogen invasion, degenerative process and inflammation often involves coordinated changes in both blood and lymphatic vessels. As lymphatic vessels are involved in the initiation and resolution of inflammation and regulation of tissue edema, VEGF family members may have important roles in myocardial lymphatics in healthy and in cardiac disease. We will review the properties of VEGF ligands and receptors concentrating on their lymphatic vessel effects first in normal myocardium and then in cardiac disease.

Simvastatin Treatment Upregulates Anti-Fibrotic Bone Morphogenetic Protein-7 Expression at Rat Cardiac Allograft Rejection.

BACKGROUND: Bone morphogenetic protein (BMP)-7 mediates ischemic tolerance and anti-fibrotic effects in various organs such as kidney and heart. Recently, reno- and podocyte-protective effects of a potent HMG-CoA reductase inhibitor, pitavastatin, were accompanied by BMP-7 upregulation. METHODS: Here, we investigated the effect of simvastatin treatment on BMP-7 expression in major MHC-mismatched rat cardiac allografts subjected to ischemia-reperfusion injury and adaptive immune activation at 10 days. RESULTS: We localized Smad2 activity and Reca-1+ fibroblast specific protein-1+ immunoreactivity, suggesting endothelial-to-mesenchymal transition, at fibrotic borderline of cardiac allografts at 10 days. Simvastatin donor and recipient combination treatment significantly upregulated cardiac allograft BMP-7 expression when compared to nontreated controls at 10 days. CONCLUSION: The beneficial effect of statin treatment on cardiac allograft may in part be mediated through the upregulation of BMP-7.

Systemic overexpression of matricellular protein CCN1 exacerbates obliterative bronchiolitis in mouse tracheal allografts.

Obliterative bronchiolitis (OB) involves airway epithelial detachment, fibroproliferation, and inflammation, resulting in chronic rejection and transplant failure. Cysteine-rich 61 (CCN1) is an integrin receptor antagonist with a context-dependent role in inflammatory and fibroproliferative processes. We used a mouse tracheal OB model to investigate the role of CCN1 in the development of lung allograft OB. C57Bl/6 mice received a systemic injection of CCN1-expressing adenoviral vectors 2 days prior to subcutaneous implantation of tracheal allografts from major MHC-mismatched BALB/c mice. We treated another group of tracheal allograft recipients with cyclic arginine-glycine-aspartic acid peptide to dissect the role of αvß3-integrin signaling in mediating CCN1 effects in tracheal allografts. Allografts were removed 4 weeks after transplantation and analyzed for luminal occlusion, inflammation, and vasculogenesis. CCN1 overexpression induced luminal occlusion (P < 0.05), fibroproliferation, and smooth muscle cell proliferation (P < 0.05). Selective activation of αvß3-integrin receptor failed to mimic the actions of CCN1, and blocking failed to inhibit the effects of CCN1 in tracheal allografts. In conclusion, CCN1 exacerbates tracheal OB by enhancing fibroproliferation via an αvß3-integrin-independent pathway. Further experiments are required to uncover its potentially harmful role in the development of OB after lung transplantation.

Donor plasma VEGF-A as a biomarker for myocardial injury and primary graft dysfunction after heart transplantation.

BACKGROUND: Vascular endothelial growth factor (VEGF)-A is an angiogenic and proinflammatory cytokine with profound effects on microvascular permeability and vasodilation. Several processes may induce VEGF-A expression in brain-dead organ donors. However, it remains unclear whether donor VEGF-A is linked to adverse outcomes after heart transplantation. METHODS: We examined plasma VEGF-A levels from 83 heart transplant donors as well as the clinical data of these donors and their respective recipients operated between 2010 and 2016. The donor plasma was analyzed using Luminex-based Multiplex and confirmed with a single-target ELISA. Based on donor VEGF-A plasma levels, the recipients were divided into 3 equal-sized groups (low VEGF <500 ng/liter, n = 28; moderate VEGF 500-3000 ng/liter, n = 28; and high VEGF >3000 ng/liter, n = 27). Biochemical and clinical parameters of myocardial injury as well as heart transplant and kidney function were followed-up for one year, while rejection episodes, development of cardiac allograft vasculopathy, and mortality were monitored for 5 years. RESULTS: Baseline parameters were comparable between the donor groups, except for age, where median ages of 40, 45, and 50 were observed for low, moderate, and high donor plasma VEGF levels groups, respectively, and therefore donor age was included as a confounding factor. High donor plasma VEGF-A levels were associated with pronounced myocardial injury (TnT and TnI), a higher inotrope score, and a higher incidence of primary graft dysfunction in the recipient after heart transplantation. Furthermore, recipients with allografts from donors with high plasma VEGF-A levels had a longer length of stay in the intensive care unit and the hospital, and an increased likelihood for prolonged renal replacement therapy. CONCLUSIONS: Our findings suggest that elevated donor plasma VEGF-A levels were associated with adverse outcomes in heart transplant recipients, particularly in terms of myocardial injury, primary graft dysfunction, and long-term renal complications. Donor VEGF-A may serve as a potential biomarker for predicting these adverse outcomes and identifying extended donor criteria.

Randomized Trial of Cholesterol Lowering With Evolocumab for Cardiac Allograft Vasculopathy in Heart Transplant Recipients.

BACKGROUND: Cardiac allograft vasculopathy is characterized by increased coronary intimal thickness and is a leading cause of death in heart transplant (HTx) recipients despite the routine use of statins. The experience with inhibitors of proprotein convertase subtilisin-kexin type 9 in HTx recipients is limited. Our hypothesis was that lowering cholesterol with the proprotein convertase subtilisin-kexin type 9inhibitor evolocumab would reduce coronary intimal thickness in these patients without compromising safety. OBJECTIVES: This double blind, randomized trial was conducted to test whether evolocumab reduces the burden of cardiac allograft vasculopathy. METHODS: Patients who had received a cardiac allograft at one of the Nordic transplant centers within the prior 4 to 8 weeks were randomized to monthly subcutaneous injections of evolocumab 420 mg or matching placebo. The primary endpoint was the baseline-adjusted maximal intimal thickness as measured by intracoronary ultrasound after 12 months' treatment. RESULTS: The trial enrolled 128 patients between June 2019 and May 2022. Matched pairs of coronary ultrasound images were available for 56 patients assigned to evolocumab and 54 patients assigned to placebo. At 12 months, the adjusted mean difference in the maximal intimal thickness between the 2 arms was 0.017 mm (95% CI: -0.006 to 0.040; P = 0.14). The mean reduction in low-density lipoprotein cholesterol with evolocumab compared with placebo was 1.11 mmol/L (95% CI: 0.86-1.37 mmol/L). The use of evolocumab was not associated with an increase in adverse events. CONCLUSIONS: Twelve months of treatment with evolocumab substantially reduced low-density lipoprotein cholesterol but did not reduce maximal coronary intimal thickness in HTx recipients. (Cholesterol Lowering With EVOLocumab to Prevent Cardiac Allograft Vasculopathy in De-novo Heart Transplant Recipients [EVOLVD]; NCT03734211).

Critical role of VEGF-C/VEGFR-3 signaling in innate and adaptive immune responses in experimental obliterative bronchiolitis.

Chronic inflammation, a hallmark of obliterative bronchiolitis, is known to induce lymphangiogenesis. We therefore studied the role of lymphangiogenic vascular endothelial growth factor C (VEGF-C), its receptor VEGFR-3, and lymphangiogenesis during development of experimental obliterative bronchiolitis [ie, obliterative airway disease (OAD)] in rat tracheal allografts. The functional importance of VEGF-C was investigated by adenovirus-mediated overexpression of VEGF-C (AdVEGF-C), and by inhibition of VEGF-C activity with VEGFR-3-Ig (AdVEGFR-3-Ig). Analyses included histology, immunohistochemistry, and real-time RT-PCR 10 and 30 days after transplantation. In the course of OAD development, lymphangiogenesis was induced in the airway wall during the alloimmune response, which was reversed by cyclosporine A in a dose-dependent fashion. VEGF-C overexpression in tracheal allografts induced epithelial activation, neutrophil chemotaxis, and a shift toward a Th17 adaptive immune response, followed by enhanced lymphangiogenesis and the development of OAD. In contrast, inhibition of VEGF-C activity with VEGFR-3-Ig inhibited lymphangiogenesis and angiogenesis and reduced infiltration of CD4(+) T cells and the development of OAD. Lymphangiogenesis was linked to T-cell responses during the development of OAD, and VEGF-C/VEGFR-3 signaling modulated innate and adaptive immune responses in the development of OAD in rat tracheal allografts. Our results thus suggest VEGFR-3-signaling as a novel strategy to regulate T-cell responses in the development of obliterative bronchiolitis after lung transplantation.

Severe primary graft dysfunction of the heart transplant is associated with increased plasma and intragraft proinflammatory cytokine expression.

INTRODUCTION: Heart transplant results have constantly improved but primary left ventricle graft dysfunction (LV-PGD) remains a devastating complication early after transplantation. Donor and recipient systemic inflammatory response may be involved in immune activation of the transplant, and LV-PGD development. Here, we investigated donor and recipient plasma and intragraft cytokine profiles preoperatively and during LV-PGD and searched for predictive markers for LV-PGD. METHODS: Donor and recipient plasma samples (n = 74) and myocardial biopsies of heart transplants (n = 64) were analyzed. Plasma and intragraft cytokine levels were determined by multiplexed and next-generation sequencing platforms, respectively. The development of LV-PGD during the first 24 hours, and graft function and mortality up to 1 year after transplantation, were examined. RESULTS: Severe LV-PGD, but not mild or moderate LV-PGD, was significantly associated with early mortality, plasma high-sensitivity troponin elevation, and an increase in intragraft and plasma proinflammatory cytokines during reperfusion. Preoperative donor and recipient plasma cytokine levels failed to predict LV-PGD. Cytokine network analysis identified interleukins -6, -8, -10, and -18 as key players during reperfusion. Prolonged cold and total ischemia time, and increased need for red blood cell transfusions during operation were identified as clinical risk factors for severe LV-PGD. CONCLUSIONS: Severe LV-PGD was associated with a poor clinical outcome. Donor and recipient plasma cytokine profile failed to predict LV-PGD, but severe LV-PGD was associated with an increase in post-reperfusion intragraft and recipient plasma proinflammatory cytokines. Identified key cytokines may be potential therapeutic targets to improve early and long-term outcomes after heart transplantation.

Donor simvastatin treatment abolishes rat cardiac allograft ischemia/reperfusion injury and chronic rejection through microvascular protection.

BACKGROUND: Ischemia/reperfusion injury may have deleterious short- and long-term consequences for cardiac allografts. The underlying mechanisms involve microvascular dysfunction that may culminate in primary graft failure or untreatable chronic rejection. METHODS AND RESULTS: Here, we report that rat cardiac allograft ischemia/reperfusion injury resulted in profound microvascular dysfunction that was prevented by donor treatment with peroral single-dose simvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase and Rho GTPase inhibitor, 2 hours before graft procurement. During allograft preservation, donor simvastatin treatment inhibited microvascular endothelial cell and pericyte RhoA/Rho-associated protein kinase activation and endothelial cell-endothelial cell gap formation; decreased intragraft mRNA levels of hypoxia-inducible factor-1α, inducible nitric oxide synthase, and endothelin-1; and increased heme oxygenase-1. Donor, but not recipient, simvastatin treatment prevented ischemia/reperfusion injury-induced vascular leakage, leukocyte infiltration, the no-reflow phenomenon, and myocardial injury. The beneficial effects of simvastatin on vascular stability and the no-reflow phenomenon were abolished by concomitant nitric oxide synthase inhibition with N-nitro-l-arginine methyl ester and RhoA activation by geranylgeranyl pyrophosphate supplementation, respectively. In the chronic rejection model, donor simvastatin treatment inhibited cardiac allograft inflammation, transforming growth factor-ß1 signaling, and myocardial fibrosis. In vitro, simvastatin inhibited transforming growth factor-ß1-induced microvascular endothelial-to-mesenchymal transition. CONCLUSIONS: Our results demonstrate that donor simvastatin treatment prevents microvascular endothelial cell and pericyte dysfunction, ischemia/reperfusion injury, and chronic rejection and suggest a novel, clinically feasible strategy to protect cardiac allografts.

Plasma proteome of brain-dead organ donors predicts heart transplant outcome.

BACKGROUND: The pathophysiological changes related to brain death may affect the quality of the transplanted organs and expose the recipients to risks. We probed systemic changes reflected in donor plasma proteome and investigated their relationship to heart transplant outcomes. METHODS: Plasma samples from brain-dead multi-organ donors were analyzed by label-free protein quantification using high-definition mass spectrometry. Unsupervised and supervised statistical models were used to determine proteome differences between brain-dead donors and healthy controls. Proteome variation and the corresponding biological pathways were analyzed and correlated with transplant outcomes. RESULTS: Statistical models revealed that donors had a unique but heterogeneous plasma proteome with 237 of 463 proteins being changed compared to controls. Pathway analysis showed that coagulation, gluconeogenesis, and glycolysis pathways were upregulated in donors, while complement, LXR/RXR activation, and production of nitric oxide and reactive oxygen species in macrophages pathways were downregulated. In point-biserial correlation analysis, lysine-specific demethylase 3A was moderately correlated with any grade and severe PGD. In univariate and multivariate Cox regression analyses myosin Va and proteasome activator complex subunit 2 were significantly associated with the development of acute rejections with hemodynamic compromise within 30 days. Finally, we found that elevated levels of lysine-specific demethylase 3A and moesin were identified as predictors for graft-related 1-year mortality in univariate analysis. CONCLUSIONS: We show that brain death significantly changed plasma proteome signature Donor plasma protein changes related to endothelial cell and cardiomyocyte function, inflammation, and vascular growth and arteriogenesis could predict transplant outcome suggesting a role in donor evaluation.

Targeting lymphatic vessel activation and CCL21 production by vascular endothelial growth factor receptor-3 inhibition has novel immunomodulatory and antiarteriosclerotic effects in cardiac allografts.

BACKGROUND: Lymphatic network and chemokine-mediated signals are essential for leukocyte traffic during the proximal steps of alloimmune response. We aimed to determine the role of lymphatic vessels and their principal growth signaling pathway, vascular endothelial growth factor (VEGF)-C/D/VEGFR-3, during acute and chronic rejection in cardiac allografts. METHODS AND RESULTS: Analysis of heterotopically transplanted rat cardiac allografts showed that chronic rejection increased VEGF-C(+) inflammatory cell and hyaluronan receptor-1 (LYVE-1)(+) lymphatic vessel density. Allograft lymphatic vessels were VEGFR-3(+), contained antigen-presenting cells, and produced dendritic cell chemokine CCL21. Experiments with VEGFR-3/LacZ mice or mice with green fluorescent protein-positive bone marrow cells as cardiac allograft recipients showed that allograft lymphatic vessels originated almost exclusively from donor cells. Intraportal adenoviral VEGFR-3-Ig (Ad.VEGFR-3-Ig/VEGF-C/D-Trap) perfusion was used to inhibit VEGF-C/D/VEGFR-3 signaling. Recipient treatment with Ad.VEGFR-3-Ig prolonged rat cardiac allograft survival. Ad.VEGFR-3-Ig did not affect allograft lymphangiogenesis but was linked to reduced CCL21 production and CD8(+) effector cell entry in the allograft. Concomitantly, Ad.VEGFR-3-Ig reduced OX62(+) dendritic cell recruitment and increased transcription factor Foxp3 expression in the spleen. In separate experiments, treatment with a neutralizing monoclonal VEGFR-3 antibody reduced arteriosclerosis, the number of activated lymphatic vessels expressing VEGFR-3 and CCL21, and graft-infiltrating CD4(+) T cells in chronically rejecting mouse cardiac allografts. CONCLUSIONS: These results show that VEGFR-3 participates in immune cell traffic from peripheral tissues to secondary lymphoid organs by regulating allograft lymphatic vessel CCL21 production and suggest VEGFR-3 inhibition as a novel lymphatic vessel-targeted immunomodulatory therapy for cardiac allograft rejection and arteriosclerosis.

Vascular endothelial growth factor-B acts as a coronary growth factor in transgenic rats without inducing angiogenesis, vascular leak, or inflammation.

BACKGROUND: Vascular endothelial growth factor-B (VEGF-B) binds to VEGF receptor-1 and neuropilin-1 and is abundantly expressed in the heart, skeletal muscle, and brown fat. The biological function of VEGF-B is incompletely understood. METHODS AND RESULTS: Unlike placenta growth factor, which binds to the same receptors, adeno-associated viral delivery of VEGF-B to mouse skeletal or heart muscle induced very little angiogenesis, vascular permeability, or inflammation. As previously reported for the VEGF-B(167) isoform, transgenic mice and rats expressing both isoforms of VEGF-B in the myocardium developed cardiac hypertrophy yet maintained systolic function. Deletion of the VEGF receptor-1 tyrosine kinase domain or the arterial endothelial Bmx tyrosine kinase inhibited hypertrophy, whereas loss of VEGF-B interaction with neuropilin-1 had no effect. Surprisingly, in rats, the heart-specific VEGF-B transgene induced impressive growth of the epicardial coronary vessels and their branches, with large arteries also seen deep inside the subendocardial myocardium. However, VEGF-B, unlike other VEGF family members, did not induce significant capillary angiogenesis, increased permeability, or inflammatory cell recruitment. CONCLUSIONS: VEGF-B appears to be a coronary growth factor in rats but not in mice. The signals for the VEGF-B-induced cardiac hypertrophy are mediated at least in part via the endothelium. Because cardiomyocyte damage in myocardial ischemia begins in the subendocardial myocardium, the VEGF-B-induced increased arterial supply to this area could have therapeutic potential in ischemic heart disease.

[Application of extracorporeal membrane oxygenation therapy (ECMO) in the treatment of severe adult respiratory distress syndrome]. / ECMO eli kehonulkoinen happeuttaminen aikuisten vaikeassa hengitysvajauksessa.

Extracorporeal oxygenator is used in severe respiratory and/or circulatory failure that is intractable to other therapies. In ECMO therapy, poorly oxygenated blood is pumped through an extracorporeal oxygenator and directed back to the patient's circulation. The therapy can be utilized to maintain the homeostasis of the organ system during circulatory or respiratory failure resulting from a disease. Due to risk of complications, ECMO should be used with caution on carefully selected patients. For a severely ill patient ECMO can be life-saving when started early.

[Mechanical support for the heart and circulation in adults]. / Sydämen ja verenkierron mekaaninen tuki aikuisilla.

In severe, acute or chronic heart failure, the heart and the circulation can be mechanically supported, if the patient's life is in danger despite maximal drug therapy, and other cardiologic or heart surgery treatment options or a suitable heart transplant are not available. Long-term prognosis of those treated with mechanical support has improved in the 2000's. This is based on technically advanced equipment, improved treatment practices, properly targeted patient selection and more accurate timing of therapy.

Failing Heart Transplants and Rejection-A Cellular Perspective.

The median survival of patients with heart transplants is relatively limited, implying one of the most relevant questions in the field-how to expand the lifespan of a heart allograft? Despite optimal transplantation conditions, we do not anticipate a rise in long-term patient survival in near future. In order to develop novel strategies for patient monitoring and specific therapies, it is critical to understand the underlying pathological mechanisms at cellular and molecular levels. These events are driven by innate immune response and allorecognition driven inflammation, which controls both tissue damage and repair in a spatiotemporal context. In addition to immune cells, also structural cells of the heart participate in this process. Novel single cell methods have opened new avenues for understanding the dynamics driving the events leading to allograft failure. Here, we review current knowledge on the cellular composition of a normal heart, and cellular mechanisms of ischemia-reperfusion injury (IRI), acute rejection and cardiac allograft vasculopathy (CAV) in the transplanted hearts. We highlight gaps in current knowledge and suggest future directions, in order to improve cellular and molecular understanding of failing heart allografts.

PDGF-A, -C, and -D but not PDGF-B increase TGF-beta1 and chronic rejection in rat cardiac allografts.

OBJECTIVE: Chronic rejection is the main reason for the poor long-term survival of heart transplant recipients and is characterized by cardiac allograft inflammation, fibrosis, and arteriosclerosis. We examined the specific roles of different platelet-derived growth factor (PDGF) ligands (A-D)--potent mesenchymal cell mitogens--in rat cardiac allografts. METHODS AND RESULTS: PDGFR-alpha mRNA was upregulated in acutely-rejecting, and PDGF-A and PDGF-C mRNA in chronically-rejecting cardiac centhatn allografts. In acute rejection, PDGFR-alpha immunoreactivity increased in the media of arteries. In chronically-rejecting allografts, immunoreactivity of all PDGF ligands and receptors--except that of PDGF-B ligand--was found in the intima of arteries, and the expression of PDGF-A and PDGF-C was seen in cardiomyocytes. Intracoronary adeno-associated virus-2 (AAV2)-mediated PDGF-A and -D gene transfer enhanced cardiac allograft inflammation. AAV2-PDGF-A, AAV2-PDGF-C, and AAV2-PDGF-D significantly upregulated profibrotic TGF-beta1 mRNA and accelerated cardiac fibrosis and arteriosclerosis. In contrast, AAV2-PDGF-B did not aggravate chronic rejection. CONCLUSIONS: We found that alloimmune response induces PDGF-A, PDGF-C, and PDGF-D expression in the graft vasculature. PDGF-A, PDGF-C, and PDGF-D mediated profibrotic and proarteriosclerotic effects in transplanted hearts involving the TGF-beta1 pathway. Inhibition of signaling of all PDGF-ligands except that of PDGF-B may thus be needed to inhibit chronic rejection in cardiac allografts.