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BACKGROUND AND STUDY AIM: Secondary Aortoenteric Fistulas (sAEF) are difficult to diagnose and usually result in fatal gastrointestinal (GI) bleeding following aortic repair. Outcomes are largely dependent on a timely diagnosis, but AEFs remain challenging to identify endoscopically and are usually diagnosed on computed tomography (CT) scans. The aim of our study was optimize diagnosis of AEF by identifying patients developing GI bleeding after aortic repair, investigate their clinical course and identify factors specific to different bleeding sources. METHODS: A retrospective, single-center study capturing all patients developing upper or lower GI bleeding after aortic surgery between January 2009 and March 2020 was performed. Electronic health records were screened for diagnostic codes of the relevant procedures. Bleeding was classified into three groups: AEF with demonstrable fistula, ischemic - macroscopic ulceration plus histological confirmation or imaging and "other" due to other recognized conventional cause, such as peptic ulcer disease. RESULTS: 47 GI bleeding episodes in 39 patients were identified. Of these, 10 episodes (21%) were caused by AEF, 16 (34%) by ischemic ulceration and 21 (45%) due to other causes. Patients with AEF exhibited more frequent hemodynamic instability requiring vasopressors and had higher mortality, while ischemic ulcerations were associated with more recent operation or hypotensive episode. CONCLUSIONS: GI bleeding complications are uncommon following aortic surgery. AEF and ischemic ulceration are however frequent bleeding causes in this cohort. In patients presenting with fulminant bleeding, primary CT-scanning should be considered.
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Enfermedades de la Aorta , Hemorragia Gastrointestinal , Fístula Vascular , Enfermedades de la Aorta/complicaciones , Enfermedades de la Aorta/diagnóstico por imagen , Enfermedades de la Aorta/cirugía , Endoscopía , Hemorragia Gastrointestinal/etiología , Humanos , Estudios Retrospectivos , Tomografía Computarizada por Rayos X , Fístula Vascular/diagnóstico , Fístula Vascular/etiología , Fístula Vascular/cirugíaRESUMEN
BACKGROUND: Sepsis is a pathological host response to infection leading to vascular barrier breakdown due to elevated levels of angiopoietin-2 (Angpt-2) and vascular endothelial growth factor-A (VEGF-A). Here, we tested a novel heterodimeric bispecific monoclonal IgG1-cross antibody of Angpt-2 and VEGF - termed "A2V." METHODS: Cecal ligation and puncture was used to induce murine polymicrobial sepsis. Organs and blood were harvested for fluorescence immunohistochemistry and RT-PCR, and survival was recorded. In vitro endothelial cells were stimulated with plasma from septic shock patients costimulated with A2V or IgG antibody followed by immunocytochemistry and real-time transendothelial electrical resistance. RESULTS: Septic mice treated with A2V had a reduced induction of the endothelial adhesion molecule ICAM-1, leading to a trend towards less transmigration of inflammatory cells (A2V: 42.2 ± 1.0 vs. IgG 48.5 ± 1.7 Gr-1+ cells/HPF, p = 0.08) and reduced tissue levels of inflammatory cytokines (e.g., IL-6 mRNA: A2V 9.4 ± 3.2 vs. IgG 83.9 ± 36.7-fold over control, p = 0.03). Endothelial permeability was improved in vivo and in vitro in stimulated endothelial cells with septic plasma. Survival was improved by 38% (p = 0.02). CONCLUSION: Dual inhibition of Angpt-2 and VEGF-A improves murine sepsis morbidity and mortality, making it a potential therapeutic against vascular barrier breakdown.
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Angiopoyetina 2/antagonistas & inhibidores , Sepsis/tratamiento farmacológico , Factor A de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Animales , Permeabilidad Capilar/efectos de los fármacos , Células Cultivadas , Humanos , Molécula 1 de Adhesión Intercelular/análisis , Masculino , Ratones , Ratones Endogámicos C57BL , Sepsis/mortalidadRESUMEN
Background: Timely diagnosis of vascular graft infections is of major importance in vascular surgery. The detection of causative microorganisms is needed for specific medical treatment, but conventional culture is often slow, insensitive and inconclusive due to antibiotic pre-treatment. Detection of bacterial DNA by polymerase chain reaction (PCR) might bypass these problems. We hypothesised that multiplex PCR (mPCR) is feasible, fast and sensitive to detect causative microorganisms in vascular graft infections. Patients and methods: We performed a pilot observational prospective study comparing conventional culture and a commercial mPCR. Inclusion criteria were: confirmed graft infection, suspicious imaging, clinical suspicion, anastomotic aneurysm and repeated graft occlusion. Diagnostic methods were performed using identical samples. Time to result, microorganisms and antibiotic resistance in both groups were compared using Student's t-test or nonparametric tests. Results: 22 samples from 13 patients were assessed and 11 samples were negative for bacteria. Some showed multiple germs. In total, we found 15 different organisms. 13 samples matched, 9 had non-concordant results. Out of the mismatches 3 microorganisms identified in PCR were not detected by culture. Time to result with PCR was shorter (median 5 h vs. 72 h, p < 0.001) than with culture. No resistance genes were detected by mPCR, but conventional culture allowed susceptibility testing and revealed resistance in 5 samples. Conclusions: mPCR seems to be a feasible and quick tool to detect causes of vascular graft infections within 24 h and might be helpful in antibiotic pre-treated patients. The detection of antibiotic resistance with mPCR needs improvement for clinical practice.
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Infecciones , Reacción en Cadena de la Polimerasa Multiplex , ADN Bacteriano , Humanos , Proyectos Piloto , Estudios ProspectivosRESUMEN
BACKGROUND:: Patients undergoing vascular surgery are prone to perioperative organ injury because of both higher prevalence of cardiovascular risk factors and the extent of surgery. Early detection of organ failure is essential to facilitate appropriate medical care. Midregional pro-adrenomedullin (MR-proADM) has been investigated in acute medical care settings to guide clinical decision-making regarding patient pathways and to identify patients prone to imminent cardiovascular or inflammatory complications. In this study, we evaluated the impact of perioperative MR-proADM levels as an early marker of perioperative cardiovascular and inflammatory stress reactions and kidney injury. METHODS:: The study was conducted as a monocentric, prospective, noninterventional trial at Hannover Medical School, Germany. A total of 454 consecutive patients who underwent open vascular surgery were followed from the day prior to until 30 days after surgery. The composite primary end point was defined as the occurrence of major adverse cardiac events (MACEs), acute kidney injury (AKI), or systemic inflammatory response syndrome (SIRS). Measurements were correlated with both medical history and postoperative MACE, AKI, or SIRS using univariate and multivariate regression analysis. RESULTS:: One hundred thirty-nine (31%) of the patients reached the primary end point within the study interval. Midregional pro-adrenomedullin change was associated with the combined primary end point and with the intensity of surgical trauma. Midregional pro-adrenomedullin change was increased in patients reaching the secondary end points, SIRS (optimal cutoff: 0.2 nmol/L) and AKI (optimal cutoff: 0.7 nmol/L), but not in patients with MACEs. CONCLUSION:: Increased levels of MR-proADM within the perioperative setting (1) were linked to the invasiveness of surgery and (2) identified patients with ongoing loss of renal function. Increased MR-proADM levels may therefore identify a subgroup of patients prone to excessive cardiovascular stress but did not directly correlate with adverse cardiac events. Consistently low levels of MR-proADM may identify a subgroup of patients with acceptable low risk to guide discharge from high-density care units.
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Adrenomedulina/sangre , Complicaciones Intraoperatorias/sangre , Fragmentos de Péptidos/sangre , Precursores de Proteínas/sangre , Insuficiencia Renal/sangre , Síndrome de Respuesta Inflamatoria Sistémica/sangre , Procedimientos Quirúrgicos Vasculares/efectos adversos , Anciano , Anciano de 80 o más Años , Biomarcadores/sangre , Vías Clínicas , Femenino , Humanos , Complicaciones Intraoperatorias/fisiopatología , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios ProspectivosRESUMEN
OBJECTIVES: Tie2 is a tyrosine kinase receptor expressed by endothelial cells that maintains vascular barrier function. We recently reported that diverse critical illnesses acutely decrease Tie2 expression and that experimental Tie2 reduction suffices to recapitulate cardinal features of the septic vasculature. Here we investigated molecular mechanisms driving Tie2 suppression in settings of critical illness. DESIGN: Laboratory and animal research, postmortem kidney biopsies from acute kidney injury patients and serum from septic shock patients. SETTING: Research laboratories and ICU of Hannover Medical School, Harvard Medical School, and University of Groningen. PATIENTS: Deceased septic acute kidney injury patients (n = 16) and controls (n = 12) and septic shock patients (n = 57) and controls (n = 22). INTERVENTIONS: Molecular biology assays (Western blot, quantitative polymerase chain reaction) + in vitro models of flow and transendothelial electrical resistance experiments in human umbilical vein endothelial cells; murine cecal ligation and puncture and lipopolysaccharide administration. MEASUREMENTS AND MAIN RESULTS: We observed rapid reduction of both Tie2 messenger RNA and protein in mice following cecal ligation and puncture. In cultured endothelial cells exposed to tumor necrosis factor-α, suppression of Tie2 protein was more severe than Tie2 messenger RNA, suggesting distinct regulatory mechanisms. Evidence of protein-level regulation was found in tumor necrosis factor-α-treated endothelial cells, septic mice, and septic humans, all three of which displayed elevation of the soluble N-terminal fragment of Tie2. The matrix metalloprotease 14 was both necessary and sufficient for N-terminal Tie2 shedding. Since clinical settings of Tie2 suppression are often characterized by shock, we next investigated the effects of laminar flow on Tie2 expression. Compared with absence of flow, laminar flow induced both Tie2 messenger RNA and the expression of GATA binding protein 3. Conversely, septic lungs exhibited reduced GATA binding protein 3, and knockdown of GATA binding protein 3 in flow-exposed endothelial cells reduced Tie2 messenger RNA. Postmortem tissue from septic patients showed a trend toward reduced GATA binding protein 3 expression that was associated with Tie2 messenger RNA levels (p < 0.005). CONCLUSIONS: Tie2 suppression is a pivotal event in sepsis that may be regulated both by matrix metalloprotease 14-driven Tie2 protein cleavage and GATA binding protein 3-driven flow regulation of Tie2 transcript.
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Receptor TIE-2/fisiología , Sepsis/fisiopatología , Adulto , Anciano , Animales , Células Cultivadas , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Persona de Mediana Edad , Estudios Prospectivos , Receptor TIE-2/biosíntesisRESUMEN
OBJECTIVE: The recent withdrawal of a targeted sepsis therapy has diminished pharmaceutical enthusiasm for developing novel drugs for the treatment of sepsis. Angiopoietin-2 is an endothelial-derived protein that potentiates vascular inflammation and leakage and may be involved in sepsis pathogenesis. We screened approved compounds for putative inhibitors of angiopoietin-2 production and investigated underlying molecular mechanisms. DESIGN: Laboratory and animal research plus prospective placebo-controlled randomized controlled trial (NCT00529139) and retrospective analysis (NCT00676897). SETTING: Research laboratories of Hannover Medical School and Harvard Medical School. PATIENTS: Septic patients/C57Bl/6 mice and human endothelial cells. INTERVENTIONS: Food and Drug Administration-approved library screening. MEASUREMENTS AND MAIN RESULTS: In a cell-based screen of more than 650 Food and Drug Administration-approved compounds, we identified multiple members of the 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitor drug class (referred to as statins) that suppressed angiopoietin-2. Simvastatin inhibited 3-hydroxy-3-methyl-glutaryl-CoA reductase, which in turn activated PI3K-kinase. Downstream of this signaling, PI3K-dependent phosphorylation of the transcription factor Foxo1 at key amino acids inhibited its ability to shuttle to the nucleus and bind cis-elements in the angiopoietin-2 promoter. In septic mice, transient inhibition of angiopoietin-2 expression by liposomal siRNA in vivo improved absolute survival by 50%. Simvastatin had a similar effect, but the combination of angiopoietin-2 siRNA and simvastatin showed no additive benefit. To verify the link between statins and angiopoietin-2 in humans, we performed a pilot matched case-control study and a small randomized placebo-controlled trial demonstrating beneficial effects on angiopoietin-2. CONCLUSIONS: 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors may operate through a novel Foxo1-angiopoietin-2 mechanism to suppress de novo production of angiopoietin-2 and thereby ameliorate manifestations of sepsis. Given angiopoietin-2's dual role as a biomarker and candidate disease mediator, early serum angiopoietin-2 measurement may serve as a stratification tool for future trials of drugs targeting vascular leakage.
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Angiopoyetina 2/antagonistas & inhibidores , Angiopoyetina 2/fisiología , Factores de Transcripción Forkhead/fisiología , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Sepsis/tratamiento farmacológico , Simvastatina/uso terapéutico , Anciano , Animales , Estudios de Casos y Controles , Reposicionamiento de Medicamentos , Femenino , Proteína Forkhead Box O1 , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Persona de Mediana EdadRESUMEN
BACKGROUND: Pericytes surround endothelial cells at the perivascular interface. Signaling between endothelial cells and pericytes is crucial for capillary homeostasis, as pericytes stabilize vessels and regulate many microvascular functions. Recently it has been shown that pericytes are able to detach from the vascular wall and contribute to fibrosis by becoming scar-forming myofibroblasts in many organs including the kidney. At the same time, the loss of pericytes within the perivascular compartment results in vulnerable capillaries which are prone to instability, pathological angiogenesis, and, ultimately, rarefaction. AIMS: This review will give an overview of pericyte-endothelial cell interactions, summarize the signaling pathways that have been identified to be involved in pericyte detachment from the vascular wall, and present pathological endothelial responses in the context of disease of the kidney.
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Células Endoteliales/citología , Células Endoteliales/fisiología , Pericitos/citología , Pericitos/fisiología , Enfermedades Vasculares/patología , Enfermedades Vasculares/fisiopatología , Capilares/citología , Capilares/fisiología , Comunicación Celular/fisiología , Cicatriz/patología , Cicatriz/fisiopatología , Fibrosis/patología , Fibrosis/fisiopatología , HumanosRESUMEN
Microvascular disease, a characteristic of acute and chronic kidney diseases, leads to rarefaction of peritubular capillaries (PTCs), promoting secondary ischemic injury, which may be central to disease progression. Bidirectional signaling by EphB4 receptor and ephrinB2 ligand is critical for angiogenesis during murine development, suggesting that ephrinB2 reverse signaling may have a role in renal angiogenesis induced by injury or fibrosis. Here, we found that ephrinB2 reverse signaling is activated in the kidney only after injury. In mice lacking the PDZ intracellular signaling domain of ephrinB2 (ephrinB2 ΔV), angiogenesis was impaired and kidney injury led to increased PTC rarefaction and fibrosis. EphrinB2 ΔV primary kidney pericytes migrated more than wild-type pericytes and were less able to stabilize capillary tubes in three-dimensional culture and less able to stimulate synthesis of capillary basement membrane. EphrinB2 ΔV primary kidney microvascular endothelial cells migrated and proliferated less than wild-type microvascular endothelial cells in response to vascular endothelial growth factor A and showed less internalization and activation of vascular endothelial growth factor receptor-2. Taken together, these results suggest that PDZ domain-dependent ephrinB2 reverse signaling protects against PTC rarefaction by regulating angiogenesis and vascular stability during kidney injury. Furthermore, this signaling in kidney pericytes protects against pericyte-to-myofibroblast transition and myofibroblast activation, thereby limiting fibrogenesis.
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Lesión Renal Aguda/patología , Capilares/patología , Efrina-B2/metabolismo , Riñón/irrigación sanguínea , Riñón/patología , Receptor EphB4/metabolismo , Lesión Renal Aguda/metabolismo , Animales , Capilares/metabolismo , Células Cultivadas , Fibrosis , Ratones , Ratones Endogámicos C57BL , Neovascularización Fisiológica , Transducción de SeñalRESUMEN
Hyperammonemia is a life-threatening condition, the prognosis of which depends on a rapid reduction of ammonia. If a hepatic cause is excluded, the differential diagnosis is broad and even in adulthood includes hereditary metabolic diseases. Here, the case of a 25-year-old female patient with severe hyperammonemia refractory to standard therapy is described and the relevance of extracorporeal elimination of ammonia emphasized.
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Hiperamonemia , Femenino , Humanos , Adulto , Hiperamonemia/diagnóstico , Amoníaco/metabolismo , Pronóstico , Diagnóstico DiferencialRESUMEN
Kidney pericytes are progenitors of scar-forming interstitial myofibroblasts that appear after injury. The function of kidney pericytes as microvascular cells and how these cells detach from peritubular capillaries and migrate to the interstitial space, however, are poorly understood. Here, we used an unbiased approach to identify genes in kidney pericytes relevant to detachment and differentiation in response to injury in vivo, with a particular focus on genes regulating proteolytic activity and angiogenesis. Kidney pericytes rapidly activated expression of a disintegrin and metalloprotease with thrombospondin motifs-1 (ADAMTS1) and downregulated its inhibitor, tissue inhibitor of metalloproteinase 3 (TIMP3) in response to injury. Similarly to brain pericytes, kidney pericytes bound to and stabilized capillary tube networks in three-dimensional gels and inhibited metalloproteolytic activity and angiogenic signaling in endothelial cells. In contrast, myofibroblasts did not have these vascular stabilizing functions despite their derivation from kidney pericytes. Pericyte-derived TIMP3 stabilized and ADAMTS1 destabilized the capillary tubular networks. Furthermore, mice deficient in Timp3 had a spontaneous microvascular phenotype in the kidney resulting from overactivated pericytes and were more susceptible to injury-stimulated microvascular rarefaction with an exuberant fibrotic response. Taken together, these data support functions for kidney pericytes in microvascular stability, highlight central roles for regulators of extracellular proteolytic activity in capillary homoeostasis, and identify ADAMTS1 as a marker of activation of kidney pericytes.
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Proteínas ADAM/fisiología , Enfermedades Renales/fisiopatología , Riñón/irrigación sanguínea , Pericitos/fisiología , Inhibidor Tisular de Metaloproteinasa-3/fisiología , Proteína ADAMTS1 , Animales , Capilares/fisiopatología , Adhesión Celular , Células Cultivadas , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Miofibroblastos/fisiología , Neovascularización Fisiológica , Análisis de Secuencia por Matrices de Oligonucleótidos , Obstrucción Ureteral/metabolismo , Factor A de Crecimiento Endotelial Vascular/fisiologíaRESUMEN
BACKGROUND: Necrotizing fasciitis (NF) is a serious infectious disease that can initially place the patient's life in danger and, after successful surgical and antibiotic treatment, leaves extensive wounds with sometimes even exposed bones and tendons. Autologous skin grafts are not always possible or require adequate wound bed preparation. Novel intact fish skin grafts (iFSGs; Kerecis® Omega3 Wound, Kerecis hf, Isafjördur, Iceland) have already shown their potential to promote granulation in many other wound situations. Faster wound healing rates and better functional and cosmetic outcomes were observed due to their additionally postulated anti-inflammatory and analgesic properties. Therefore, iFSGs may also be essential in treating NF. We present our initial experience with iFSGs in treating leg wounds after NF and review the literature for the current spectrum of clinical use of iFSGs. CASE PRESENTATIONS: We present two male patients (aged 60 and 69 years) with chronic or acute postsurgical extensive leg ulcers six weeks and six days after necrotizing fasciitis, respectively. Both suffered from diabetes mellitus without vascular pathologies of the lower limbs. A single application of one pre-meshed (Kerecis® Graftguide) and one self-meshed 300 cm2 iFSG (Kerecis® Surgiclose) was performed in our operation room after extensive surgical debridement and single circles of negative wound pressure therapy. Application and handling were easy. An excellent wound granulation was observed, even in uncovered tibia bone and tendons, accompanied by pain relief in both patients. Neither complications nor allergic reactions occurred. The patients received autologous skin grafting with excellent functional and cosmetic outcomes. CONCLUSIONS: iFSGs have the potential to play a significant role in the future treatment of NF due to the fast promotion of wound granulation and pain relief. Our experience may encourage surgeons to use iFSGs in NF patients, although high-quality, large-sized studies are still required to confirm these results. The observed effects of iFSGs on wounds associated with NF may be transferred to other wound etiologies as well.
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Introduction: Synthetic vascular grafts perform poorly in small-caliber (<6mm) anastomoses, due to intimal hyperplasia and thrombosis, whereas homografts are associated with limited availability and immunogenicity, and bioprostheses are prone to aneurysmal degeneration and calcification. Infection is another important limitation with vascular grafting. This study developed a dual-component graft for small-caliber reconstructions, comprising a decellularized tibial artery scaffold and an antibiotic-releasing, electrospun polycaprolactone (PCL)/polyethylene glycol (PEG) blend sleeve. Methods: The study investigated the effect of nucleases, as part of the decellularization technique, and two sterilization methods (peracetic acid and γ-irradiation), on the scaffold's biological and biomechanical integrity. It also investigated the effect of different PCL/PEG ratios on the antimicrobial, biological and biomechanical properties of the sleeves. Tibial arteries were decellularized using Triton X-100 and sodium-dodecyl-sulfate. Results: The scaffolds retained the general native histoarchitecture and biomechanics but were depleted of glycosaminoglycans. Sterilization with peracetic acid depleted collagen IV and produced ultrastructural changes in the collagen and elastic fibers. The two PCL/PEG ratios used (150:50 and 100:50) demonstrated differences in the structural, biomechanical and antimicrobial properties of the sleeves. Differences in the antimicrobial activity were also found between sleeves fabricated with antibiotics supplemented in the electrospinning solution, and sleeves soaked in antibiotics. Discussion: The study demonstrated the feasibility of fabricating a dual-component small-caliber graft, comprising a scaffold with sufficient biological and biomechanical functionality, and an electrospun PCL/PEG sleeve with tailored biomechanics and antibiotic release.
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Microvascular pericytes and perivascular fibroblasts have recently been identified as the source of scar-producing myofibroblasts that appear after injury of the kidney. We show that cross talk between pericytes and endothelial cells concomitantly dictates development of fibrosis and loss of microvasculature after injury. When either platelet-derived growth factor receptor (R)-ß signaling in pericytes or vascular endothelial growth factor (VEGF)R2 signaling in endothelial cells was blocked by circulating soluble receptor ectodomains, both fibrosis and capillary rarefaction were markedly attenuated during progressive kidney injury. Blockade of either receptor-mediated signaling pathway prevented pericyte differentiation and proliferation, but VEGFR2 blockade also attenuated recruitment of inflammatory macrophages throughout disease progression. Whereas injury down-regulated angiogenic VEGF164, the dys-angiogenic isomers VEGF120 and VEGF188 were up-regulated, suggesting that pericyte-myofibroblast differentiation triggers endothelial loss by a switch in secretion of VEGF isomers. These findings link fibrogenesis inextricably with microvascular rarefaction for the first time, add new significance to fibrogenesis, and identify novel therapeutic targets.
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Endotelio Vascular/patología , Riñón/irrigación sanguínea , Riñón/patología , Microvasos/patología , Pericitos/metabolismo , Transducción de Señal , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismo , Animales , Capilares/metabolismo , Capilares/patología , Proliferación Celular , Endotelio Vascular/metabolismo , Fibrosis , Humanos , Inmunidad Innata , Riñón/metabolismo , Ratones , Microvasos/metabolismo , Neovascularización Patológica/complicaciones , Neovascularización Patológica/metabolismo , Pericitos/patología , Isoformas de Proteínas/metabolismo , Receptor beta de Factor de Crecimiento Derivado de Plaquetas/antagonistas & inhibidores , Receptor beta de Factor de Crecimiento Derivado de Plaquetas/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Receptor 2 de Factores de Crecimiento Endotelial Vascular/antagonistas & inhibidoresRESUMEN
One of the main risk factors for the presence of carotid stenosis and carotid-related stroke is age. The aim of this review article is to present the current state of knowledge on age-related vascular changes using carotid stenosis as an example.Vascular aging (vascular senescence) is a decrease of structural and functional properties of the vessel wall that takes place on different levels. At the multicellular level an increase in vessel volume and diameter as well as intima media thickness occurs with age mainly due to atherosclerotic changes in the vessel wall. At the cellular and extracellular levels there is a decrease in elastin fibers, smooth muscle cells, and total cellularity, an increase in lipid, cholesterol, and calcium phosphate deposition as well as neovascularization. The causes of vascular aging at the molecular level include, in particular oxidative stress, chronic inflammatory response, mitochondrial dysfunction, epigenetic changes, dysregulation of the expression of non-coding RNAs (ncRNAs), and the increase in senescence. Age-related loss of tissue healing and repair capacity make plaques more vulnerable and, in the case of the carotid artery, more susceptible to ischemic stroke.Increasing knowledge of the influence of aging on the epigenetics and ncRNAs in atherosclerotic plaques can in the future more accurately quantify individual patient risk and contribute to the development of targeted therapeutic strategies; however, further studies are needed in this field to understand the full extent of vascular aging and its associated diseases so that these can then be specifically targeted.
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PURPOSE OF REVIEW: Until recently kidney pericytes were little known. This review will update readers about key new findings concerning pericyte abundance, function in kidney vascular biology and major role in fibrogenesis. Moreover readers will become familiar with the central role of pericyte-endothelial interactions in peritubular capillary health or rarefaction and the pivotal role these may play in renal ischemia. RECENT FINDINGS: Pericytes are stromal cells that partially cover capillary walls. Pericytes were recently identified as collagen-1α1 producing cells in healthy adult kidney. Kinetic mathematical modeling studies indicated they were the source of scar-forming myofibroblasts. Comprehensive fate mapping of kidney stroma confirmed that pericytes and perivascular fibroblasts, not epithelium, were the major source of myofibroblasts. Blockade of pericyte-endothelial cross-talk in response to renal injury prevents both microvascular rarefaction and interstitial fibrosis. The detachment of pericytes from endothelium under pathological conditions and differentiation into myofibroblasts leads to pericyte deficiency at the microvascular interstitial interface, resulting in unstable microvasculature and thence vessel rarefaction, ultimately leading to nephron ischemia. To develop new therapeutic strategies, a better understanding of not only pericyte detachment and migration from capillaries, but also pericyte-endothelial crosstalk in health and injury is required. SUMMARY: This review summarizes the functional role of pericytes during fibrosis, focusing on myofibroblast origins and pericyte-endothelial cross-talk.
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Fibrosis/etiología , Riñón/patología , Pericitos/fisiología , Animales , Factores de Transcripción Forkhead/genética , Humanos , Pericitos/citología , Proteínas/genética , ARN no TraducidoRESUMEN
INTRODUCTION: Endothelial activation leading to vascular barrier breakdown plays an essential role in the pathophysiology of multiple-organ dysfunction syndrome (MODS) in sepsis. Increasing evidence suggests that the function of the vessel-protective factor Angiopoietin-1 (Ang-1), a ligand of the endothelial-specific Tie2 receptor, is inhibited by its antagonist Angiopoietin-2 (Ang-2) during sepsis. In order to reverse the effects of the sepsis-induced suppression of Ang-1 and elevation of Ang-2 we aimed to investigate whether an intravenous injection of recombinant human (rh) Ang-1 protects against MODS in murine sepsis. METHODS: Polymicrobiological abdominal sepsis was induced by cecal ligation and puncture (CLP). Mice were treated with either 1 µg of intravenous rhAng-1 or control buffer immediately after CLP induction and every 8h thereafter. Sham-operated animals served as time-matched controls. RESULTS: Compared to buffer-treated controls, rhAng-1 treated septic mice showed significant improvements in several hematologic and biochemical indicators of MODS. Moreover, rhAng-1 stabilized endothelial barrier function, as evidenced by inhibition of protein leakage from lung capillaries into the alveolar compartment. Histological analysis revealed that rhAng-1 treatment attenuated leukocyte infiltration in lungs and kidneys of septic mice, probably due to reduced endothelial adhesion molecule expression in rhAng-1 treated mice. Finally, the protective effects of rhAng-1 treatment were reflected by an improved survival time in a lethal CLP model. CONCLUSIONS: In a clinically relevant murine sepsis model, intravenous rhAng-1 treatment alone is sufficient to significantly improve a variety of sepsis-associated organ dysfunctions and survival time, most likely by preserving endothelial barrier function. Further studies are needed to pave the road for clinical application of this therapy concept.
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Angiopoyetina 1/uso terapéutico , Insuficiencia Multiorgánica/tratamiento farmacológico , Insuficiencia Multiorgánica/etiología , Proteínas Recombinantes/uso terapéutico , Sepsis/complicaciones , Sepsis/tratamiento farmacológico , Sepsis/mortalidad , Angiopoyetina 1/genética , Angiopoyetina 1/metabolismo , Angiopoyetina 2/metabolismo , Animales , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Humanos , Ratones , Insuficiencia Multiorgánica/patología , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptor TIE-2 , Proteínas Recombinantes/genética , Sepsis/patología , Tasa de SupervivenciaAsunto(s)
Arterias , Placa Aterosclerótica , Bacterias , Humanos , Inflamación , Pierna/irrigación sanguíneaRESUMEN
Vascularization of tissue engineered implants is crucial for their survival and integration in the recipient's body. Pre-vascularized, fibrin-based implants offer a solution since low concentration fibrin hydrogels (1 mg/mL) have been shown to promote tube formation of endothelial cells in co-culture with adipogenic stem cells. However, higher fibrinogen concentrations (> 20 mg/mL) enabling the fabrication of stable implants are necessary.We here characterized fibrin gels of 1-30 mg/mL for their rheological properties and whether they support tube formation of endothelial cell-adipogenic stem cell co-cultures for up to 7 days. Moreover, 20 mg/mL gels containing preformed channels and endothelial cell-adipogenic stem cell co-culture were perfused continuously in a customized flow chamber with 3.9 dyn/cm2 for 12 days and analyzed for capillary formation.Rheology of fibrin gels showed increasing stability proportional to fibrinogen concentration with 20 mg/mL gels having a storage module of 465 Pa. Complex tube networks stable for 7 days were observed at 1-5 mg/mL gels whereas higher concentrations showed initial sprouting only. However, perfusion of 20 mg/mL fibrin gels resulted in endothelialized pore formation in several layers of the gel with endothelial cell-adipogenic stem cell co-culture.Thus, perfusion supports the formation of capillary-like structures in fibrin gels that are too dense for spontaneous tube formation under static conditions. Future studies are necessary to further increase pore density and to investigate proper nutrition of tissue-specific target cells in the scaffold.
Asunto(s)
Fibrina/farmacología , Regeneración Tisular Dirigida/métodos , Hidrogeles/farmacología , Repitelización/fisiología , Ingeniería de Tejidos , Andamios del Tejido , Implantes Absorbibles , Capilares/crecimiento & desarrollo , Humanos , Perfusión/métodos , Prótesis e Implantes/normas , Reología , Ingeniería de Tejidos/instrumentación , Ingeniería de Tejidos/métodosRESUMEN
Background: Specific microRNAs (miRs) have been implicated in the pathophysiology of atherosclerosis and may represent interesting diagnostic and therapeutic targets in carotid stenosis. We hypothesized that the levels of specific circulating miRs are altered in patients with symptomatic carotid stenosis (sCS) in comparison to those in patients with asymptomatic carotid stenosis (aCS) planned to undergo carotid endarterectomy (CEA). We also studied whether miR levels are associated with plaque vulnerability and stability over time after CEA. Methods: Circulating levels of vascular-enriched miR-92a, miR-126, miR-143, miR-145, miR-155, miR-210, miR-221, miR-222, and miR-342-3p were determined in 21 patients with sCS and 23 patients with aCS before CEA and at a 90-day follow-up. Transcranial Doppler ultrasound for detection of microembolic signals (MES) in the ipsilateral middle cerebral artery was performed prior to CEA. Carotid plaques were histologically analyzed. Results: Mean levels of miRs were not considerably different between groups and were only marginally higher in sCS than aCS concerning miR-92a, miR-210, miR-145, and miR-143 with the best evidence concerning miR-92a. After adjustment for vascular risk factors and statin pre-treatment, the effect sizes remained essentially unchanged. At follow-up, however, these modest differences remained uncorroborated. There were no relevant associations between miR-levels and MES or histological plaque vulnerability features. Conclusions: This study does not provide evidence for strong associations between specific circulating miRs and symptomatic state in a collective of comprehensively characterized patients with carotid stenosis. Further work is needed to elucidate the role of circulating miRs as targets in advanced carotid atherosclerosis.
RESUMEN
Inflammatory processes are crucial in atherosclerosis and atherothrombosis. This study aimed to identify a cytokine-pattern that is associated with plaque-vulnerability or symptomatic state in comprehensively investigated patients with symptomatic (sCS) and asymptomatic carotid stenosis (aCS). Twenty-two patients with sCS and twenty-four patients with aCS undergoing carotid endarterectomy (CEA) were considered. A cytokine-panel was measured in plasma-specimens prior to surgery and at a 90 day follow-up. Doppler-ultrasound detecting microembolic signals (MES) in the ipsilateral middle cerebral artery was performed. Carotid plaques were analysed regarding histopathological criteria of plaque-vulnerability and presence of chemokine receptor CXCR4. Correction for multiple comparisons and logistic regression analysis adjusting for vascular risk factors, grade of stenosis, antithrombotic and statin pretreatment were applied. In sCS-patients higher plasma-levels of Fractalkine (CX3CL1), IFN-α2, IL-1ß, IL-2, IL-3, IL-7 were found compared to aCS-patients. CXCR4-expression on inflammatory cells was more evident in sCS- compared to aCS-plaques and was associated with vulnerability-criteria. In contrast, plasma-cytokine-levels were not related to CXCR4-expression or other vulnerability-criteria or MES. However, in both groups distinct inter-cytokine correlation patterns, which persisted at follow-up and were more pronounced in the sCS-group could be detected. In conclusion, we identified a distinct cytokine/chemokine-network in sCS-patients with elevated and closely correlated mediators of diverse functions.