GP VI-Mediated Platelet Activation and Procoagulant Activity Aggravate Inflammation and Aortic Wall Remodeling in Abdominal Aortic Aneurysm.

BACKGROUND: Platelets play an important role in cardiovascular and cerebrovascular diseases. Abdominal aortic aneurysm (AAA) is a highly lethal, atherosclerosis-related disease with characteristic features of progressive dilatation of the abdominal aorta and degradation of the vessel wall, accompanied by chronic inflammation. Platelet activation and procoagulant activity play a decisive role in the AAA pathology as they might trigger AAA development in both mice and humans. METHODS: The present study investigated the impact of the major platelet collagen receptor GP (platelet glycoprotein) VI in pathophysiological processes underlying AAA initiation and progression. For experimental AAA induction in mice, PPE (porcine pancreatic elastase) and the external PPE model were used. RESULTS: Genetic deletion of GP VI offered protection of mice against aortic diameter expansion in experimental AAA. Mechanistically, GP VI deficiency resulted in decreased inflammation with reduced infiltration of neutrophils and platelets into the aortic wall. Furthermore, remodeling of the aortic wall was improved in the absence of GP VI, as indicated by reduced MMP (matrix metalloproteinase)-2/9 and OPN (osteopontin) plasma levels and an enhanced α-SMA (α-smooth muscle actin) content within the aortic wall, accompanied by reduced cell apoptosis. Consequently, an elevation in intima/media thickness and elastin content was observed in GP VI-deficient PPE mice, resulting in a significantly reduced aortic diameter expansion and reduced aneurysm incidence. In patients with AAA, enhanced plasma levels of soluble GP VI and fibrin, as well as fibrin accumulation within the intraluminal thrombus might serve as new biomarkers to detect AAA early. Moreover, we hypothesize that GP VI might play a role in procoagulant activity and thrombus stabilization via binding to fibrin. CONCLUSIONS: In conclusion, our results emphasize the potential need for a GP VI-targeted antiplatelet therapy to reduce AAA initiation and progression, as well as to protect patients with AAA from aortic rupture.

Abdominal Aortic Endograft Implantation Immediately Induces Vascular Stiffness Gradients That May Promote Adverse Aortic Neck Dilatation: Results of A Porcine Ex Vivo Study.

PURPOSE: Endovascular aortic repair (EVAR) is the method of choice for most abdominal aortic aneurysm (AAA) patients requiring intervention. However, chronic aortic neck dilatation (AND) following EVAR progressively weakens the structural seal between vessel and endograft and compromises long-term results of the therapy. This experimental ex vivo study seeks to investigate mechanisms of AND. MATERIALS AND METHODS: Porcine abdominal aortas (n=20) were harvested from slaughterhouse pigs and connected to a mock circulation. A commercially available endograft was implanted (n=10) or aortas were left untreated as controls (n=10). Vascular circumferential strain was assessed via ultrasound in defined aortic segments as a parameter of aortic stiffness. Histology and aortic gene expression analysis were performed to investigate potential changes of aortic wall structure and molecular differences due to endograft implantation. RESULTS: We found that endograft implantation acutely induces a significant stiffness gradient directly at the interface between stented and unstented aortic segments under pulsatile pressure. Comparing stented aortas with unstented controls, we detected increased aortic expression levels of inflammatory cytokines (Il6 and Ccl2) and matrix metalloproteinases (Mmp2 and Mmp9) after 6 hours of pulsatile pressurization. This effect, however, was abolished when repeating the same experiment under 6 hours of static pressure. CONCLUSIONS: We identified endograft-induced aortic stiffness gradients as an early trigger of inflammatory aortic remodeling processes that might promote AND. These results highlight the importance of adequate endograft designs to minimize vascular stiffness gradients and forestall late complications, such as AND. CLINICAL IMPACT: AND may compromise the long-term results following endovascular aortic repair. However, the mechanisms behind the underlying detrimental aortic remodeling are still unclear. In this study we find that endograft-induced aortic stiffness gradients induce an inflammatory aortic remodeling response consistent with AND. This novel pathomechanistic insight may guide the design of new aortic endografts that minimize vascular stiffness gradients and forestall late complications such as AND.

Nicotine Affects Murine Aortic Stiffness and Fatigue Response During Supraphysiological Cycling.

Nicotine exposure is a major risk factor for several cardiovascular diseases. Although the deleterious effects of nicotine on aortic remodeling processes have been studied to some extent, the biophysical consequences are not fully elucidated. In this investigation, we applied quasi-static and dynamic loading to quantify ways in which exposure to nicotine affects the mechanical behavior of murine arterial tissue. Segments of thoracic aortas from C57BL/6 mice exposed to 25 mg/kg/day of subcutaneous nicotine for 28 days were subjected to uniaxial tensile loading in an open-circumferential configuration. Comparing aorta segments from nicotine-treated mice relative to an equal number of control counterparts, stiffness in the circumferential direction was nearly twofold higher (377 kPa ± 165 kPa versus 191 kPa ± 65 kPa, n = 5, p = 0.03) at 50% strain. Using a degradative power-law fit to fatigue data at supraphysiological loading, we observed that nicotine-treated aortas exhibited significantly higher peak stress, greater loss of tension, and wider oscillation band than control aortas (p ≤ 0.01 for all three variables). Compared to simple stress relaxation tests, fatigue cycling is shown to be more sensitive and versatile in discerning nicotine-induced changes in mechanical behavior over many cycles. Supraphysiological fatigue cycling thus may have broader potential to reveal subtle changes in vascular mechanics caused by other exogenous toxins or pathological conditions.

The JOTEC iliac branch device for exclusion of hypogastric artery aneurysms: ABRAHAM study.

OBJECTIVE: Hypogastric artery aneurysms (HAAs) are rare but life-threatening in cases of rupture. Open or endovascular techniques traditionally aimed at occluding the hypogastric artery (HA) have considerable risk of pelvic ischemia. Iliac branch devices (IBDs) are indicated for aortoiliac aneurysms; however, they have also been used lately for HAAs. Currently, there are no reports about patient outcomes focusing on HAA therapy using IBDs. We retrospectively analyzed early and midterm outcomes using IBDs for HAAs. METHODS: Patients who received IBDs for HAAs at our department from January 1, 2012, through March 1, 2018, were included. Exclusion criteria were as follows: no HA involvement, emergency procedures, and HA stent grafting without IBD. Perioperative and follow-up data were collected from medical records. RESULTS: There were 18 IBDs (only IBD, n = 4; IBD + endovascular aneurysm repair [EVAR], n = 7; IBD ± EVAR + side branch occlusion, n = 7) implanted into 14 male patients (76 ± 4 [70-83] years). There were no intraoperative complications, and the technical success rate was 100%. After 19 ± 11 (2-39) months of follow-up, two hybrid (external iliac artery occlusion, n = 1; EVAR graft kinking, n = 1) and four endovascular reinterventions due to two type IB (side branch coiling + stent graft extension) and two type IIIB (stent grafting) endoleaks were required. One IBD-related type II endoleak revealed constant aneurysm diameters during follow-up. One small type IB endoleak was self-limited. Estimated freedom from reintervention was 31% ± 23% at 2.7 years. The clinical success and patency rate was 100%. The IBD-related mortality was 0%. CONCLUSIONS: The IBD for HAA shows good early and midterm results. Adequate sealing of HA landing zones and side branch occlusion are technically challenging but crucial to prevent type IB and type II endoleaks.

MicroRNA-Mediated Therapy Modulating Blood-Brain Barrier Disruption Improves Vascular Cognitive Impairment.

OBJECTIVE: There are currently no effective treatments for the prevention of dementia associated with vascular cognitive impairment. MicroRNAs regulate gene expression at the post-transcriptional level and play key roles in vascular disorders. TNFα (tumor necrosis factor-α) regulates blood-brain barrier breakdown through modification of cerebral tight junctions. Here, we sought key TNFα-responsive microRNAs that might influence blood-brain barrier breakdown via cerebral tight junction disruption in vascular cognitive impairment. APPROACH AND RESULTS: Using a mouse model of vascular cognitive impairment, chronic cerebral hypoperfusion within the white matter was induced with bilateral common carotid artery stenosis (BCAS) surgery. TNFα gene expression was increased in white matter post-BCAS surgery, and TNFα stimulation decreased claudin-5, ZO-1 (tight-junction protein 1), and occludin gene expression in murine brain endothelial cells. In silico analysis predicted 8 candidate microRNAs as regulators of claudin-5, ZO-1, and occludin gene expression. Of these, only miR-501-3p was upregulated by TNFα in vitro and was upregulated in the white matter after BCAS surgery. Further, miR-501-3p directly bound to the 3'-untranslated region of human ZO-1 and downregulated transendothelial electric resistance. In vivo administration of a locked nucleic acid -modified antisense oligonucleotide versus miR-501-3p suppressed BCAS-induced reduction of ZO-1 gene expression and blood-brain barrier disruption within the white matter and significantly ameliorated working memory deficits after BCAS surgery. CONCLUSIONS: We here provide the first evidence that the TNFα-miR-501-3p-ZO-1 axis plays an important role in the pathogenesis of cerebral hypoperfusion-induced working memory deficits and white matter lesions, as a result of blood-brain barrier breakdown via tight junction disruption. Therapeutic manipulation of miR-501-3p holds promise for limiting vascular cognitive impairment progression.

Systemic Upregulation of IL-10 (Interleukin-10) Using a Nonimmunogenic Vector Reduces Growth and Rate of Dissecting Abdominal Aortic Aneurysm.

Objective- Recruitment of immunologic competent cells to the vessel wall is a crucial step in formation of abdominal aortic aneurysms (AAA). Innate immunity effectors (eg, macrophages), as well as mediators of adaptive immunity (eg, T cells), orchestrate a local vascular inflammatory response. IL-10 (interleukin-10) is an immune-regulatory cytokine with a crucial role in suppression of inflammatory processes. We hypothesized that an increase in systemic IL-10-levels would mitigate AAA progression. Approach and Results- Using a single intravenous injection protocol, we transfected an IL-10 transcribing nonimmunogenic minicircle vector into the Ang II (angiotensin II)-ApoE-/- infusion mouse model of AAA. IL-10 minicircle transfection significantly reduced average aortic diameter measured via ultrasound at day 28 from 166.1±10.8% (control) to 131.0±5.8% (IL-10 transfected). Rates of dissecting AAA were reduced by IL-10 treatment, with an increase in freedom from dissecting AAA from 21.5% to 62.3%. Using flow cytometry of aortic tissue from minicircle IL-10-treated animals, we found a significantly higher percentage of CD4+/CD25+/Foxp3 (forkhead box P3)+ regulatory T cells, with fewer CD8+/GZMB+ (granzyme B) cytotoxic T cells. Furthermore, isolated aortic macrophages produced less TNF-α (tumor necrosis factor-α), more IL-10, and were more likely to be MRC1 (mannose receptor, C type 1)-positive alternatively activated macrophages. These results concurred with gene expression analysis of lipopolysaccharide-stimulated and Ang II-primed human peripheral blood mononuclear cells. Conclusions- Taken together, we provide an effective gene therapy approach to AAA in mice by enhancing antiinflammatory and dampening proinflammatory pathways through minicircle-induced augmentation of systemic IL-10 expression.

Controlled isoflurane anesthesia exposure is required for reliable behavioral testing in murine surgical models.

We investigated the effects of variations in anesthesia exposure time prior to conducting anxiety response behavioral testing in sham controls from an experimental murine model. The staying time in the center area of the Open Field test in the "long exposure" group was significantly decreased compared to that of the "short exposure" group. Significant correlation was found between anesthesia time and the duration of staying time in the center area. We conclude that anesthesia time may have a significant impact on behavioral anxiety testing in this context, and advise careful control of this parameter in protocol optimization in related surgical animal models.

Chronic Mesenteric Ischemia: Patient Outcomes Using Open Surgical Revascularization.

BACKGROUND: Chronic mesenteric ischemia (CMI) is a rare disease. Open treatment (OT) remains a valuable treatment option. We analyzed patient outcomes after OT and investigated health-related quality of life (HRQoL). METHODS: Data were analyzed retrospectively. The investigation period was from January 1, 2001, to December 31, 2014. We investigated mortality and patency rates using Kaplan-Meier analysis. HRQoL was measured using a 36-item health survey. Various statistical methods were employed. RESULTS: A total of 100 patients (celiac trunk [TC: n = 23], superior mesenteric artery [SMA: n = 26], or both [n = 51]) were included. Median follow-up was 5 ± 35 months. One-year survival rate for TC was 75 ± 11%, for SMA: 79 ± 10%, and for both: 96 ± 3%. TC 5-year survival was 75 ± 11% (SMA: 57 ± 16%: both: 80 ± 8%). Obesity and the length of hospital stay were independently associated with patient survival (p < 0.05). Primary 1-year patency rate was 60 ± 13% for TC (SMA: 86 ± 10%; both: 71 ± 8%) and secondary 1-year patency rate was 84 ± 9% for TC (SMA: 100%; both: 79 ± 7%). HRQoL was inferior compared to the German normative data (p < 0.05). CONCLUSION: CMI overlaps between gastrointestinal and vascular surgery. OT is safe, and simultaneous revascularization of the TC and the SMA does not affect mortality. Patients would not necessarily benefit from OT in terms of HRQoL.

Spontaneous rupture of an isolated iliac artery dissection in a young man because of cystic medial degeneration Erdheim-Gsell.

BACKGROUND: Rupture of isolated iliac artery dissections is a life-threatening event and has not been associated with cystic medial degeneration (CMD) Erdheim-Gsell. METHODS: A young man presented to our emergency unit in a critical hemodynamic condition. Computed tomography scan feigned the rupture of an internal iliac artery. RESULTS: Surprisingly, we found a ruptured dissection of the common iliac artery during open surgery. Reconstruction was done by Dacron graft interposition between common and internal iliac artery and external iliac artery implantation into the graft. Histology revealed CMD. CONCLUSIONS: Spontaneous iliac artery dissection and rupture can be caused by CMD and requires immediate surgical intervention.

Assessment of essential characteristics of two different scaffolds for tendon in situ regeneration.

PURPOSE: Rotator cuff tears are challenging as the rate of re-ruptures remains high. Thus, new therapeutic strategies need to be developed. Tendon in situ regeneration (TSR) attempts to produce cell-scaffold constructs in vitro, which can produce tendinous tissue of high quality after replantation. Therefore, it is essential to find suitable scaffolds that can provide acceptable biofunctionality and biocompatibility. This study compares characteristics of scaffolds for in situ regeneration: a polyglycolic acid/PDS scaffold (PP-sca) (Ethisorb, Ethicon, Germany) and a collagen sponge (col-spo) (TissueTek, Germany) with a basal strengthening membrane. METHODS: Tendon-derived cells (TDCs) were isolated from the long head of the biceps tendon. Gene expression for collagen type I, collagen type III, decorin, scleraxis and tenomodulin was analysed in the third cell passage. Cell proliferation in cell seeded scaffolds was tested using a WST-1 assay. In addition, the tensile strength of both scaffolds was measured using a universal-testing machine (Zwick/Roell, Ulm, Germany). RESULTS: The results from this study indicate a genotypic drift during the in vitro cultivation of the TDCs. The PP-sca showed good biofunctional results, including low initial loss of cells after cell seeding. The proliferation rates were approximately equal in each type of scaffold. The col-spo provided superior tensile strength compared with the PP-sca (p < 0.01). CONCLUSION: Overall, the col-spo seems to be more suitable for TSR. It may become a clinical alternative in the future to achieve more satisfying results, concerning function and pain. LEVEL OF EVIDENCE: Experimental study/case series, Level IV.

A 61-year-old man with disseminated intravascular coagulation: a case report.

BACKGROUND: Disseminated intravascular coagulation (DIC) can frequently be observed in patients with severe inflammatory response. It is still correlated with a poor prognosis. Activation of coagulation activity leads to occlusions of small vessels resulting in various organ failure symptoms. In addition, secondary fibrinolysis leads to an increased risk of bleedings and means a therapeutic dilemma. Here, we present a case of a 61-year-old Caucasian man with a severe case of DIC and its clinical complications. METHODS: We report the case of a man with a severe case of DIC. Data collection was performed retrospectively. RESULTS: We report the case of a 61-year-old Caucasian man with contact to pigeon droppings in his medical history. This was followed by a rhinopharyngitis, an exanthema, and a recurring priapism. Thrombotic occlusions were predominant on admission, and necrosis of the lower legs, the hands, and the genital resulted in amputation. Hypoperfusion of the rectum and the bladder lead to the creation of a descendostoma and an uretrostoma. Anticoagulation was managed by continuous infusion of unfractionated heparin and activated protein C supplementation. Long-term anticoagulation is managed with rivaroxaban. CONCLUSIONS: Cryptococcus soil inhalation may cause severe DIC resulting in extremity amputations; however, effective anticoagulation and activated protein C supplementation might extenuate the progress. As multiple complications might occur, an interdisciplinary cooperation is essential.

Comparative Evaluation of the Short-Term Outcome of Different Endovascular Aortic Arch Procedures.

Objectives: There are several endovascular treatment options to treat aortic arch and thoracic aortic pathologies with custom-made or surgeon-modified aortic stent grafts. This study seeks to assess endovascular treatment methods for aortic arch and thoracic aortic pathologies with no acceptable proximal landing zone for standard thoracic endovascular aortic repair (TEVAR), comparing different treatment methods and evaluating technical success, intraoperative parameters and short-term outcomes. Methods: All patients undergoing elective or emergency endovascular treatment of aortic arch and thoracic aortic pathologies, with no acceptable landing zone for standard TEVAR, between 1 January 2010 and 31 March 2024, at the University Hospital Düsseldorf, Germany were included. An acceptable landing zone was defined as a minimum of 2 cm for sufficient sealing. All patients were not suitable for open surgery. Patients were categorized by an endovascular treatment method for a comprehensive comparison of pre-, intra- and postoperative variables. IBM SPSS29 was used for data analysis. Results: The patient cohort comprised 21 patients, predominantly males (81%), with an average age of 70.9 ± 9 years with no acceptable proximal landing zone for standard TEVAR procedure. The most treated aortic pathologies were penetrating aortic ulcers and chronic post-dissection aneurysms. Patients were sub-grouped according to the applied procedure as follows: five patients with chimney thoracic endovascular aortic repair (chTEVAR), seven patients with in situ fenestrated thoracic endovascular aortic repair (isfTEVAR), six patients with custom-made fenestrated thoracic endovascular aortic repair (cmfTEVAR) and three patients with custom-made branched thoracic endovascular aortic repair (cmbTEVAR). Emergency procedures involved two patients. There were significant differences in the total procedure and fluoroscopy time, as well as in contrast agent usage among the treatment groups. cmfTEVAR had the shortest total procedure time, while chTEVAR exhibited the highest contrast agent usage. The overall mortality rate among all procedures was 9.5% (two patients) and 4.7% for elective procedures, respectively. Deaths were associated with either retrograde type A dissection or stent graft infection. Both patients were treated with chTEVAR. There was one minor and one major stroke; these patients were treated with isfTEVAR. No endoleak occurred during any procedure. The reintervention rate for chTEVAR was 20% and 0% for all other procedures during the in-hospital stay. The patients who were treated with cmfTEVAR had no complications, the shortest operating and fluoroscopy time, and less contrast agent was needed in comparison with other treatment methods. Conclusions: Complex endovascular procedures of the aortic arch with custom-made or surgeon-modified aortic stent grafts offer a safe solution, with acceptable complication rates for patients who are not suitable for open aortic arch repair. In terms of procedure-related parameters and complication rates, a custom-made fenestrated TEVAR is potentially advantageous compared to the other endovascular techniques.

A Two Stage Open and Interventional Therapeutic Approach for an Inferior Pancreaticoduodenal Artery Aneurysm With Coeliac Artery Occlusion.

Introduction: Visceral artery aneurysms (VAAs) are rare but have a high mortality rate in cases of rupture, especially for pancreaticoduodenal artery aneurysms (PDAAs). A hybrid approach is presented for a challenging case with inferior PDAA (iPDAA) with concomitant coeliac artery (CA) occlusion and a variant arterial supply to the liver. Report: A 61 year old patient complained of postprandial pain associated with elevated liver enzymes and impaired hepatic synthesis capacity. The left hepatic artery (LHA) originated from an occluded CA, whereas the right hepatic artery (RHA) originated directly from the superior mesenteric artery (SMA) proximal to the iPDAA. Due to the anatomical variant, an endovascular only approach via iPDAA embolisation could have posed a critical risk to the arterial supply of the liver. Therefore, the initial plan was to first secure liver perfusion via endovascular revascularisation of the CA, before conducting a coil embolisation of the iPDAA. However, endovascular CA revascularisation failed due to a complete and fixed occlusion. As an alternative therapeutic approach, open surgical aorto-visceral autologous bypass ensured arterial supply of the liver, which now enabled safe exclusion of the iPDAA via interventional coil embolisation. This two stage hybrid strategy resulted in iPDAA exclusion and was followed by symptom relief and normalised hepatic synthesis capacity. Discussion: This case demonstrates the continued need for open visceral bypass surgery to ensure organ perfusion, if the latter depends on an aneurysmal artery. In such a situation, visceral bypass surgery can be considered in challenging anatomical scenarios, which demonstrates the relevance of endovascular and open procedures. In conclusion, both procedures can be combined in individualised therapy approaches to maximise patient benefit.

Angiotensin Receptor-Neprilysin Inhibition (Sacubitril/Valsartan) Reduces Structural Arterial Stiffness in Middle-Aged Mice.

BACKGROUND: Increasing arterial stiffness is a prominent feature of the aging cardiovascular system. Arterial stiffening leads to fundamental alterations in central hemodynamics with widespread detrimental implications for organ function resulting in significant morbidity and death, and specific therapies to address the underlying age-related structural arterial remodeling remain elusive. The present study investigates the potential of the recently clinically available dual angiotensin receptor-neprilysin inhibitor (ARNI) sacubitril/valsartan (LCZ696) to counteract age-related arterial fibrotic remodeling and stiffening in 1-year-old mice. METHODS AND RESULTS: Treatment of in 1-year-old mice with ARNI (sacubitril/valsartan), in contrast to angiotensin receptor blocker monotherapy (valsartan) and vehicle treatment (controls), significantly decreases structural aortic stiffness (as measured by in vivo pulse-wave velocity and ex vivo aortic pressure myography). This phenomenon appears, at least partly, independent of (indirect) blood pressure effects and may be related to a direct antifibrotic interference with aortic smooth muscle cell collagen production. Furthermore, we find aortic remodeling and destiffening due to ARNI treatment to be associated with improved parameters of cardiac diastolic function in aged mice. CONCLUSIONS: This study provides preclinical mechanistic evidence indicating that ARNI-based interventions may counteract age-related arterial stiffening and may therefore be further investigated as a promising strategy to improve cardiovascular outcomes in the elderly.

Crosstalk of platelets with macrophages and fibroblasts aggravates inflammation, aortic wall stiffening, and osteopontin release in abdominal aortic aneurysm.

AIMS: Abdominal aortic aneurysm (AAA) is a highly lethal disease with progressive dilatation of the abdominal aorta accompanied by degradation and remodelling of the vessel wall due to chronic inflammation. Platelets play an important role in cardiovascular diseases, but their role in AAA is poorly understood. METHODS AND RESULTS: The present study revealed that platelets play a crucial role in promoting AAA through modulation of inflammation and degradation of the extracellular matrix (ECM). They are responsible for the up-regulation of SPP1 (osteopontin, OPN) gene expression in macrophages and aortic tissue, which triggers inflammation and remodelling and also platelet adhesion and migration into the abdominal aortic wall and the intraluminal thrombus (ILT). Further, enhanced platelet activation and pro-coagulant activity result in elevated gene expression of various cytokines, Mmp9 and Col1a1 in macrophages and Il-6 and Mmp9 in fibroblasts. Enhanced platelet activation and pro-coagulant activity were also detected in AAA patients. Further, we detected platelets and OPN in the vessel wall and in the ILT of patients who underwent open repair of AAA. Platelet depletion in experimental murine AAA reduced inflammation and ECM remodelling, with reduced elastin fragmentation and aortic diameter expansion. Of note, OPN co-localized with platelets, suggesting a potential role of OPN for the recruitment of platelets into the ILT and the aortic wall. CONCLUSION: In conclusion, our data strongly support the potential relevance of anti-platelet therapy to reduce AAA progression and rupture in AAA patients.

Time-dependent effects of cellulose and gelatin-based hemostats on cellular processes of wound healing.

Introduction: Oxidized regenerated cellulose-based (ORC - TABOTAMP), oxidized non-regenerated cellulose-based (ONRC - RESORBA CELL), and gelatin-based (GELA - GELITA TUFT-IT) hemostats are commonly used in surgery. However, their impact on the wound healing process remains largely unexplored. We here assess time-dependent effects of exposure to these hemostats on fibroblast-related wound healing processes. Material and methods: Hemostats were applied to fibroblast cell cultures for 5-10 (short-), 30 and 60 min (intermediate-) and 24 h (long-term). Representative images of the hemostat degradation process were obtained, and the pH value was measured. Cell viability, apoptosis and migration were analyzed after the above exposure times at 3, 6 and 24 h follow-up. Protein levels for tumor necrosis factor α (TNF-α) and transforming-growth factor ß (TGF-ß) were assessed. Results: ORC and ONRC reduced pH values during degradation, while GELA proved to be pH-neutral. Hemostat structural integrity was prolonged for GELA (vs. ORC and ONRC). TGF-ß and TNF-α levels were reduced for ORC and ONRC (vs. GELA and control) (p < 0.05). Further, exposure of ORC and ONRC for longer than 5-10 min reduced cell viability vs. GELA and control at 3 h post-exposure (p < 0.05). Similarly, cell migration was impaired with ORC and ONRC exposure longer than 60 min at 24 h follow-up (p < 0.05). Conclusions: Short-term exposure to ORC and ONRC impairs relevant wound healing-related processes in fibroblasts, and alters protein levels of key mediating cytokines. GELA does not show similar effects. We conclude that GELA may be preferred over ORC and ONRC over short-, intermediate- and long-term exposures. Future validation of the clinical relevance is warranted.

Collagen type I and decorin expression in tenocytes depend on the cell isolation method.

BACKGROUND: The treatment of rotator cuff tears is still challenging. Tendon tissue engineering (TTE) might be an alternative in future. Tenocytes seem to be the most suitable cell type as they are easy to obtain and no differentiation in vitro is necessary. The aim of this study was to examine, if the long head of the biceps tendon (LHB) can deliver viable tenocytes for TTE. In this context, different isolation methods, such as enzymatic digestion (ED) and cell migration (CM), are investigated on differences in gene expression and cell morphology. METHODS: Samples of the LHB were obtained from patients, who underwent surgery for primary shoulder arthroplasty. Using ED as isolation method, 0.2% collagenase I solution was used. Using CM as isolation method, small pieces of minced tendon were put into petri-dishes. After cell cultivation, RT-PCR was performed for collagen type I, collagen type III, decorin, tenascin-C, fibronectin, Scleraxis, tenomodulin, osteopontin and agreccan. RESULTS: The total number of isolated cells, in relation to 1 g of native tissue, was 14 times higher using ED. The time interval for cell isolation was about 17 hours using ED and approximately 50 days using CM. Cell morphology in vitro was similar for both isolation techniques. Higher expression of collagen type I could be observed in tenocyte-like cell cultures (TLCC) using ED as isolation method (p < 0.05), however decorin expression was higher in TLCC using CM as isolation method (p < 0.05). Dedifferentiation potential seemed to be similar for both isolation techniques. CONCLUSION: In summary tenocyte-like cells can be obtained with both isolation methods (ED and CM) from the LHB. As no obvious disadvantage could be seen using ED, this method is more suitable for clinical use, as time for cell isolation is shorter and a remarkably higher number of cells can be obtained. However, both isolation methods can further be improved.

Translating mouse models of abdominal aortic aneurysm to the translational needs of vascular surgery.

INTRODUCTION: Abdominal aortic aneurysm (AAA) is a condition that has considerable socioeconomic impact and an eventual rupture is associated with high mortality and morbidity. Despite decades of research, surgical repair remains the treatment of choice and no medical therapy is currently available. Animal models and, in particular, murine models, of AAA are a vital tool for experimental in vivo research. However, each of the different models has individual limitations and provide only partial mimicry of human disease. This narrative review addresses the translational potential of the available mouse models, highlighting unanswered questions from a clinical perspective. It is based on a thorough presentation of the available literature and more than a decade of personal experience, with most of the available models in experimental and translational AAA research. RESULTS: From all the models published, only the four inducible models, namely the angiotensin II model (AngII), the porcine pancreatic elastase perfusion model (PPE), the external periadventitial elastase application (ePPE), and the CaCl2 model have been widely used by different independent research groups. Although the angiotensin II model provides features of dissection and aneurysm formation, the PPE model shows reliable features of human AAA, especially beyond day 7 after induction, but remains technically challenging. The translational value of ePPE as a model and the combination with ß-aminopropionitrile to induce rupture and intraluminal thrombus formation is promising, but warrants further mechanistic insights. Finally, the external CaCl2 application is known to produce inflammatory vascular wall thickening. Unmet translational research questions include the origin of AAA development, monitoring aneurysm growth, gender issues, and novel surgical therapies as well as novel nonsurgical therapies. CONCLUSION: New imaging techniques, experimental therapeutic alternatives, and endovascular treatment options provide a plethora of research topics to strengthen the individual features of currently available mouse models, creating the possibility of shedding new light on translational research questions.

Outflow Through Aortic Side Branches Drives False Lumen Patency in Type B Aortic Dissection.

Objective: Thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD) aims to induce false lumen (FL) thrombosis by sealing intimal tears between the true (TL) and the FL, and blocking the inflow into the FL. Incomplete thrombosis of the FL is correlated with poor clinical outcome. We hypothesize that the number of major and minor branches arising from the FL affects FL patency and may negatively influence TEVAR induced FL thrombosis. Methods: Computed tomography (CT)-scans from 89 patients diagnosed with TBAD [best medical treatment (BMT) n = 52, TEVAR n = 37] from two high-volume vascular surgery centers were analyzed retrospectively. Analysis included evaluation of the FL patency status, the number, location and size of intimal tears, and the presence of minor and major side branches originating from the FL. Multiple regression analysis was conducted to evaluate obtained parameters as predictors for FL thrombosis status. Results: In univariate analysis, the strongest correlation for FL patency was found for the number of major (R = 0.79) and minor (R = 0.86) side branches originating from the FL. When applying a multiple linear regression model, the number of major (normalized beta 0.37; P < 0.001) and minor (normalized beta 0.41; P < 0.01) side branches arising from the FL were valid predictors for the axial length of the patent and non-patent FL, and additionally determined the length of the patent FL at 12-month follow-up in patients that underwent TEVAR. Conclusions: Our data suggest that the number of minor side branches that originate from the FL in TBAD is an important determinant of FL patency, to a greater degree than previously assumed.

Exosome miR-501-3p Elevation Contributes to Progression of Vascular Stiffness.

Background: Tight junction (TJ) disruption and dysfunction are involved in the progression of arteriosclerosis. miR-501-3p regulates endothelial TJ protein-1, resulting in TJ disruption. Because exosomal microRNAs can travel to distant tissues and influence cell behavior, patients with elevated miR-501-3p may experience accelerated vascular disease progression secondary to miR-501-3p-induced reductions in TJ. This study investigated whether plasma exosome miR-501-3p levels are associated with vascular stiffness, an indicator for arteriosclerotic changes. Methods and Results: Fifty-one subjects (mean [±SD] age 70±8 years, 37% male) enrolled in a medical checkup program were recruited to the study. Brachial-ankle arterial pulse wave velocity (baPWV) and plasma exosome miR-501-3p expression were measured. Patients were divided into 2 groups depending on whether their miR-501-3p ∆Ct values were above ("High"; n=24) or below ("Low"; n=27) the cut-off levels determined by receiver operating characteristic (ROC) curve analysis. Median (interquartile range) baPWV levels were significantly higher in the miR-501-3p High than Low group (1,664 [1,496-1,859] vs. 1,450 [1,353-1,686] cm/s, respectively; P<0.05). Multivariate logistic regression analysis showed a significant association between increased baPWV and High miR-501-3p expression (odds ratio 4.66). At follow-up visits (mean 62 months later), baPWV remained significantly higher in the miR-501-3p High than Low group (1,830 [1,624-2,056] vs. 1,620 [1,377-1,816] cm/s, respectively; P<0.05). Conclusions: High expression levels of exosome miR-501-3p contribute to arteriosclerotic changes.