Hemocompatibility of blood-contacting biomaterials is one of the most important criteria for their successful
applicability. Thus, extensive
analyses according to ISO 10993-4 are required prior to ...clinical applications. In this review, we summarize essential aspects regarding the evaluation of the hemocompatibility of biomaterials and the required
analyses for determining the blood compatibility. Static, agitated, or shear flow models are used to perform hemocompatibility studies. Before and after the incubation of the test material with fresh human blood, hemolysis, cell counts, and the activation of platelets, leukocytes, coagulation and complement system are analyzed. Furthermore, the surface of biomaterials are evaluated concerning attachment of blood cells, adsorption of proteins, and generation of thrombus and fibrin networks.
Aneurysms pose life-threatening risks due to the dilatation of the arteries and carry a high risk of rupture. Despite continuous research efforts, there are still no satisfactory or clinically ...effective pharmaceutical treatments for this condition. Accelerated inflammatory processes during aneurysm development lead to increased levels of matrix metalloproteinases (MMPs) and destabilization of the vessel wall through the degradation of the structural components of the extracellular matrix (ECM), mainly collagen and elastin. Tissue inhibitors of metalloproteinases (TIMPs) directly regulate MMP activity and consequently inhibit ECM proteolysis. In this work, the synthesis of TIMP-1 protein was increased by the exogenous delivery of synthetic TIMP-1 encoding mRNA into aortic vessel tissue in an attempt to inhibit MMP-9. In vitro, TIMP-1 mRNA transfection resulted in significantly increased TIMP-1 protein expression in various cells. The functionality of the expressed protein was evaluated in an appropriate ex vivo aortic vessel model. Decreased MMP-9 activity was detected using in situ zymography 24 h and 48 h post microinjection of 5 µg TIMP-1 mRNA into the aortic vessel wall. These results suggest that TIMP-1 mRNA administration is a promising approach for the treatment of aneurysms.
Delivery of synthetic mRNAs for tissue regeneration Steinle, Heidrun; Weber, Josefin; Stoppelkamp, Sandra ...
Advanced drug delivery reviews,
December 2021, 2021-12-00, 20211201, Volume:
179
Journal Article
Peer reviewed
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In recent years, nucleic acid-based therapeutics have gained increasing importance as novel treatment options for disease prevention and treatment. Synthetic messenger RNAs (mRNAs) ...are promising nucleic acid-based drugs to transiently express desired proteins that are missing or defective. Recently, synthetic mRNA-based vaccines encoding viral proteins have been approved for emergency use against COVID-19. Various types of vehicles, such as lipid nanoparticles (LNPs) and liposomes, are being investigated to enable the efficient uptake of mRNA molecules into desired cells. In addition, the introduction of novel chemical modifications into mRNAs increased the stability, enabled the modulation of nucleic acid-based drugs, and increased the efficiency of mRNA-based therapeutic approaches. In this review, novel and innovative strategies for the delivery of synthetic mRNA-based therapeutics for tissue regeneration are discussed. Moreover, with this review, we aim to highlight the versatility of synthetic mRNA molecules for various applications in the field of regenerative medicine and also discuss translational challenges and required improvements for mRNA-based drugs.
Several diseases are caused by missing or defective synthesis of proteins due to genetic or acquired disorders. In recent years, in vitro transcribed (IVT) messenger RNA (mRNA)-based therapy for de ...novo protein expression in cells has increased in importance. Thereby, desired proteins can be produced in cells by exogenous delivery of IVT mRNA, which does not integrate into the host genome and results in transient production of target proteins. Due to the lack of genomic integration, the risk of mutation and tumor development is minimized. Different approaches using IVT mRNA have been applied to alter the expression profiles of cells by the production of proteins. IVT mRNAs encoding transcription factors have led to the highly efficient induction of pluripotency in somatic cells and generated induced pluripotent stem cells that are free of viral vector components. Furthermore, specific IVT mRNA cocktails containing more than one specific IVT mRNA can be used to directly induce the differentiation into a desired cell type. In theory, every desired mRNA can be produced in vitro and used to enable extrinsic biosynthesis of target proteins in each cell type. Cells can be engineered by IVT mRNA to express antigens on dendritic cells for vaccination and tumor treatment, surface receptors on stem cells for increased homing to distinct areas, and to produce industrial grade human growth factors. In this review, we focus on the progress and challenges in mRNA-based cell engineering approaches. Stem Cells 2017;35:68-79.
To describe the incidence, therapy and outcome of traumatic tracheobronchial injuries (TTBI) in trauma patients with multiple injuries derived from the DGU TraumaRegister. We analyzed the data on all ...patients listed on the TraumaRegister DGU (TR-DGU) in Germany between 2002 and 2015 aged 16 years or older and with an Injury Severity Score (ISS) of ≥ 9. We analyzed the data on 136,389 trauma patients, 561 of whom had suffered tracheobronchial injuries (0.4%). The majority were male (73.4%) and had a mean age of 43.7 years. In total, 84.0% of all TTBI injuries occurred secondary to blunt trauma, caused mainly by accidents (71.2%). TTBI was accompanied by several concomitant thoracic injuries such as pneumo- (41.2%) and hemothorax (23.2%), lacerations (7.8%) and contusions (32.3%) of the lung, as well as multiple rib fractures (29.6%). The severity of injury was classified via the abbreviated injury scale (AIS): 39.3% with AIS = 3, 51.3% with AIS = 4 and 60% with AIS = 5 patients underwent surgical interventions. The mortality of patients with tracheobronchial injuries was higher: 24.6%, versus 13.7% in all patients (control group). This high percentage reflects their generally severe injury burden through concomitant injuries. The incidence of TTBI in this large cohort of trauma patients is very low. However, its high mortality rate emphasizes its importance. Mortality was associated with higher ISS and AIS scores. Higher rates of concomitant injuries were therefore associated with a higher mortality rate. TTBI injuries revealed a higher rate of progression to surgical management, with 35% undergoing surgery within the first 24 h. This excessive mortality rate demonstrates a high overall injury burden in patients with TTBI and high mortality of associated injuries. A surgical intervention's impact on mortality cannot be assessed in this study, as it would need to be investigated in a case-matched study.
OBJECTIVES
Unlike aneurysm formation, the role of ascending aortic elongation in the pathogenesis of Type A aortic dissection (TAD) is largely unclear. We investigated the morphology of healthy, ...dissected and predissection aortas with a focus on ascending aortic length.
METHODS
We retrospectively compared clinical and computer tomography angiography (CTA) data from TAD patients (n = 130), patients who developed a TAD in the further clinical course (preTAD, n = 16) and healthy control patients who received a CTA for non-aortic emergencies (n = 165). The length of the ascending aorta was defined as the distance between the sinotubular junction (STJ) and the brachiocephalic trunk (BCT) at the central line, the outer and inner curvature as well as the direct distance in the frontal and sagittal planes. Additionally, the aortic diameters were analysed.
RESULTS
In the healthy controls, we found a positive correlation of age with the aortic diameter (r = 0.57) and aortic length (r = 0.42). The correlation of the respective parameters with the body size was negligible (r < 0.2). The median ascending aortic diameter at the height of the pulmonary artery in TAD (50 mm) was significantly (P < 0.001) larger compared with the respective diameter of the healthy aortas (34 mm). The diameter of the preTAD aortas (40 mm) was also significantly larger compared with the healthy controls. These proportions were similar in all the aortic diameters. The midline length of the healthy ascending aortas was 71 mm. In the preTAD and TAD aortas, the same values were 81 mm and 92 mm, respectively (both P < 0.001). We evaluated the linear distance between the STJ and the BCT in the frontal plane as an easy-to-measure parameter of aortic length. In the TAD aortas (108 mm) and preTAD aortas (97 mm), this distance was significantly longer compared with the healthy aortas (84 mm).
CONCLUSIONS
Aortic diameter might not be an optimal parameter to predict dissection. Most aortas dissect at diameters below 55 mm. Both the TAD and preTAD aortas were elongated compared with the healthy controls. Thus, aortic elongation may play a role in the pathogenesis of and may be a risk factor for TAD.
The specific hemocompatibility properties of mechanical-circulatory-support (MCS)-pump technologies have not previously been described in a comparable manner. We thus investigated the ...hemocompatibility-indicating marker of a new magnetically-levitated (MagLev) centrifugal pump (MT-Mag) in a human, whole-blood mock-loop for 360 min using the MCS devices as a driving component. We compared those results with the CentriMag adult (C-Mag) device under the same conditions according to ISO10993-4. Blood samples were analyzed via enzyme-linked-immunosorbent-assay (ELISA) for markers of coagulation, complement system, and the inflammatory response. The time-dependent activation of the coagulation system was measured by detecting thrombin-anti-thrombin complexes (TAT). The activation of the complement system was determined by increased SC5b-9 levels in both groups. A significant activation of neutrophils (PMN-elastase) was detected within the C-Mag group, but not in the MT-Mag group. However, the amount of PMN-elastase at 360 min did not differ significantly between groups. The activation of the complement and coagulation system was found to be significantly time-dependent in both devices. However, coagulation activation as determined by the TAT level was lower in the MT-Mag group than in the C-Mag group. This slight disparity could have been achieved by the optimized secondary flow paths and surface coating, which reduces the interaction of the surface with blood.
Objectives The purpose of this study is to delineate changes in aortic geometry and diameter due to dissection. Background Aortic diameter is the major criterion for elective ascending aortic ...replacement for dilated ascending aortas to prevent aortic dissection. However, recommendations are made on the basis of clinical experience and observation of diameters of previously dissected aortas. Methods Six tertiary centers on 2 continents reviewed their acute aortic dissection type A databases, which contained 1,821 patients. Included were all non-Marfan patients with nonbicuspid aortic valves who had undergone computed tomography angiography <2 years before and within 12 h after aortic dissection onset. Aortic geometry before and after dissection onset were compared. Results Altogether, 63 patients were included (27 spontaneous and 36 retrograde dissections, median age 68 57; 77 years; 54% were men). In all but 1 patient, maximum ascending aortic diameter was <55 mm before aortic dissection onset. The largest increase in diameter and volume induced by the dissection were observed in the ascending aorta (40.1 36.6; 45.3 mm vs. 52.9 46.1; 58.6 mm, +12.8 mm; p < 0.001; 124.0 90.8; 162.5 cm3 vs. 171.0 147.0; 197.0 cm3 , +47 cm3 ; p < 0.001). Mean aortic arch diameter increased from 39.8 (30.5; 42.6) mm to 46.4 (42.0; 51.6) mm (+6.6 mm; p < 0.001) and descending thoracic aorta diameter from 31.2 (27.0; 33.3) mm to 34.9 (30.9; 39.5) mm (+3.7 mm; p < 0.001). Changes in thoracic aorta geometry were similar for spontaneous and retrograde etiology. Conclusions Geometry of the thoracic aorta is affected by aortic dissection, leading to an increase in diameter that is most pronounced in the ascending aorta. Both spontaneous and retrograde dissection result in similar aortic geometry changes.
Local gene delivery systems utilizing RNA interference technology are a promising approach for therapeutic applications where site-specific release of agents is desired. Polyelectrolyte multilayers ...(PEMs) can be constructed using the layer-by-layer (LbL) technique and serve as a depot for bioactive substances, which can then be released in a controlled manner. Multilayers of hyaluronic acid/poly(ethylenimine) HA/PEI were built up with different numbers of bilayers and PEI-siRNA particles were embedded in bioactive layers for gene silencing. The increase of the bilayers and the release of siRNA particles were demonstrated by fluorescence intensity measurement with a fluorescence reader. Two different LbL techniques were tested for the reduction of ICAM-1 expression in EA.hy926: PEM build-up by dipping or drying steps, respectively. Herein, the drying technique of the bioactive layers with ICAM siRNA mediated a significant reduction of the ICAM-1 expression from 3 to 24 bilayers. The fluorescent siRNA release study and the re-culturing of the HA/PEI films demonstrated a release of the transfection particles within the first hour. The advantage of dried built-up PEMs compared to a dried monolayer of PEI-siRNA particles with the same siRNA concentration was a significant higher amount of viable cells.
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