Clinical Hemorheology and Microcirculation - Volume 48, issue 1-3
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Clinical Hemorheology and Microcirculation, a peer-reviewed international scientific journal, serves as an aid to understanding the flow properties of blood and the relationship to normal and abnormal physiology. The rapidly expanding science of hemorheology concerns blood, its components and the blood vessels with which blood interacts. It includes perihemorheology, i.e., the rheology of fluid and structures in the perivascular and interstitial spaces as well as the lymphatic system. The clinical aspects include pathogenesis, symptomatology and diagnostic methods, and the fields of prophylaxis and therapy in all branches of medicine and surgery, pharmacology and drug research.
The endeavour of the Editors-in-Chief and publishers of
Clinical Hemorheology and Microcirculation is to bring together contributions from those working in various fields related to blood flow all over the world. The editors of
Clinical Hemorheology and Microcirculation are from those countries in Europe, Asia, Australia and America where appreciable work in clinical hemorheology and microcirculation is being carried out. Each editor takes responsibility to decide on the acceptance of a manuscript. He is required to have the manuscript appraised by two referees and may be one of them himself. The executive editorial office, to which the manuscripts have been submitted, is responsible for rapid handling of the reviewing process.
Clinical Hemorheology and Microcirculation accepts original papers, brief communications, mini-reports and letters to the Editors-in-Chief. Review articles, providing general views and new insights into related subjects, are regularly invited by the Editors-in-Chief. Proceedings of international and national conferences on clinical hemorheology (in original form or as abstracts) complete the range of editorial features.
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Clinical Hemorheology and Microcirculation: the role of hemorheological and microcirculatory disturbances for epidemiology and prognosis, in particular regarding cardiovascular disorders, as well as its significance in the field of geriatrics. Authors and readers are invited to contact the editors for specific information or to make suggestions.
Abstract: Recently, it was shown that mesenchymal stem cells (MSCs) are capable of differentiating into endothelial cells which highlights the potential role of MSCs in neovascularization. In the present study, we investigated the paracrine factors responsible for tube formation in human adipose-tissue derived stem cells (ASCs). Moreover, we analyzed ASC's migration towards PDGF-BB and altered levels of proteins involved in different pathways. Freshly isolated human adipose tissue-derived stem cells were seeded onto wells coated with Matrigel and cultured in endothelial growth medium. Capillary-like tube formation was observed after 18 hours culture. Tube formation was significantly reduced in the presence of antibodies…against platelet-derived growth factor receptor beta (PDGF) or basic fibroblast growth factor (bFGF). Reverse phase proteomic assay (RPPA) was used to interrogate the expression of 139 phosphorylated or native proteins after incubation with PDGF-BB protein for 24 hours. The present data suggest, that freshly isolated ASCs contain a subpopuplation of stem cells that can form capillary like tubes which is dependent on PDGF and bFGF signaling pathway. Furthermore, Migration of human ASCs significantly increased in response to increased concentrations of PDGF-BB. In addition, incubation of ASCs with PDGF-BB altered phosphorylation of several transcription proteins that are widely expressed throughout the hematopoietic system, targeting genes that have been associated with proliferation, anti-apoptosis or differentiation.
Abstract: Angiopoietins are important growth factors for vascular development and quiescence. They are promising targets for pro- or anti-angiogenic therapies in diverse pathologies, but the mechanisms of the ANGPT/TIE2 system are complex and not well understood. In the present study, the separate and combined effects of angiopoietin 1 and angiopoietin 2 were studied, using a recently developed in vitro angiogenesis model that allows both a quantitative and qualitative evaluation of the angiogenic cascade. This cell culture model was performed with microvascular endothelial cells (ECs) originating from different vascular beds, i.e. dermal ECs and cardiac ECs. In addition, the expression of the…angiopoietins and the receptors, TIE1 and TIE2 was analyzed with RT-qPCR. This study revealed that the angiopoietins provoked a differential response in the two endothelial cultures. Both angiopoietin 1 as well as angiopoietin 2 elicited an angiogenic cascade in the dermal ECs but not in the cardiac ECs. In addition, the RT-qPCR data revealed marked differences in the endogenous expression pattern of these factors, indicating that the origin of endothelial cells might have an important impact on their angiogenic potential.
Keywords: Angiopoietin, TEK, real time RT-PCR, endothelial cells, in vitro angiogenesis
Abstract: Cost effective and safely to apply tissue engineered constructs of big volume bone transplants for the reconstruction of critical sized defects (CSD) are still not available. Key problems with synthetic scaffold materials are shrinkage and fast degradation of the scaffolds, a lack of blood supply and nutrition in the central scaffold volume and the absent or the scarce development of bone tissue along the scaffold to bridge the bone defect. The use of composite scaffolds made of biopolymers like polylactidglycolid acid (PLGA) coated and loaded with calcium phosphates (CaP) revealed promising therapeutical options for the regeneration of critical sized bone…defects. In this study interconnectively macroporous PLGA scaffolds loaded with microporous and coated with nanoporous calcium phosphates were either seeded in fixed bed bioreactors with allogenic osteogenically induced mesenchymal stem cells and implanted or implanted unseeded into critical sized femoral bone defects. As CSD a 12 mm long segment of the chinchilla femur was excised where the proximal and distal parts of the femur were fixed and stabilized by the use of an eight-hole linear reconstruction plate and secured with three bicortical screws (2.7 mm diameter) on every side of the osteotomy. Aim of the study was if we could find a way to load and coat PLGA scaffolds with CaP so that shrinkage of scaffolds could be avoided, which would favour angiogenesis, blood supply and nutrition in the construct and thus avoid central necroses regularly observed so far in transplants not vascularized and which would be inhabited by cells of he bone lineage forming new bone and healing the defect. Four weeks, at least, a notable shrinkage of the scaffolds was avoided and scaffolds were practically not degraded. Both scaffolds, loaded and loaded and coated, revealed blood vessels in all parts of the implants after 4 weeks. Only in scaffolds seeded with allogenic mesenchymal stem cells the development of bridging bone constructs between proximal and distal edges of the femur was observed after four weeks without further supplementation of growth factors. In case of the implantation of non-seeded scaffolds no obvious scaffold bound bone development could be shown.
Keywords: Critical-sized defect, PLGA/CaP, bone marrow, CaP nanoparticles
Abstract: After intra-arterial administration of radiographic contrast media (RCM), a disorder of the downstream microcirculation both with regard to blood flow velocity in microvessels and to tissue oxygen partial pressure was described. Possible factors contributing to this microcirculatory disorder are increase in plasma viscosity, a formation of echinocytes, a buckling and denudation of endothelial cells, and a disturbation of endothelial prostacyclin release. It is not known so far whether the reactions observed in the context of RCM applications are reactions of venous endothelial cells alone or also of arterial endothelial cells. Therefore, arterial ECs on ECM were exposed to the same…RCMs under identical conditions. The decrease of cell-cell contacts with an increase of denuded subendothelial matrix areas in the functionally confluent endothelial cell layer on ECM were more pronounced after a five minute exposure of endothelial cells to Iomeprol compared to Iodixanol. Changes in arterial ECs after the incubation in culture media supplemented with RCM were very subtle in comparison to changes in venous ECs.
Abstract: Cardiovascular implants such as stents or artificial vascular grafts established in clinical application to date are generally designed as long-term implants. An important requirement for the successful application of these devices is the haemocompatibility of their interface to the blood stream, which often is approached by polymeric coatings. Modern therapies are aiming at curative treatments (Regenerative Medicine) by inducing the in vivo formation of a new endothelial layer on the implant surface ensuring an optimal haemocompatibility based on the generated glycocalyx. A promising approach for providing the required biological stimulus is the secretion of pro-angiogenic factors (such as VEGF-A) by…autologous CD14+ monocytes/macrophages (mo/mΦ), which can be induced by previous angiogenic stimulation. While protocols for negative and positive immune-isolation are already established, this study was aimed to evaluate the efficacy of a positive and a negative MACS™ based immune-isolation protocol by analysing the yield, the purity and the activation status of the isolated CD14+ mo/mΦ. Both protocols enabled the isolation of more than 80% (positive isolation) and 86% (negative isolation) CD14+ mo/mΦ representing approximately 1.3 × 107 CD14+ mo/mΦ from 1 ml buffy coat. Less than 10% of these cells were also positive for CD69. Latter is an important selection criterion as CD69 is a marker characteristic for classically activated and catabolic active mo/mΦ which can negatively affect the endothelialisation process. As the negative immune-isolation protocol resulted in a cell fraction meeting the requirements on a pure cell fraction (percentage of contaminating cells < 15%) this isolation method is advantageous although it was more time consuming than the positive isolation protocol.
Abstract: Background: Atherosclerotic plaques develop at arterial regions subjected to non-uniform shear stress, and are initiated by increased leukocyte-endothelial interactions. Here we applied the in vitro model of arterial bifurcations to investigate whether telmisartan, an anti-inflammatory angiotensin II receptor blocker with PPAR-gamma activating ability, prevents monocyte recruitment by endothelium. Methods: Human umbilical vein endothelial cells (ECs) were exposed to 18 h non-uniform shear stress in bifurcating flow-through slides, followed by 2 h stimulation with 2.5 ng/mL TNF-alpha. During flow, cells were treated with telmisartan. To study cell adhesion, ECs were perfused with medium containing THP-1 monocytic cells. Adherent THP-1 monocytes were…quantified by light microscopy. Endothelial protein expression was determined by immunofluorescence. Results: Non-uniform shear stress in combination with TNF-alpha dramatically induced monocytic cell recruitment by endothelial cells. In cells treated with telmisartan (0.5–2.5 μmol/L) during exposure to non-uniform shear stress, dose-dependent inhibition of monocytic cell adhesion was observed, with about 45% reduction at 1 μmol/L. This effect was mediated by a significant reduction of endothelial VCAM-1 expression. On the contrary, the induction of E-selectin by TNF-alpha in ECs exposed to non-uniform shear stress was not affected by telmisartan. The inhibitory effect of telmisartan on monocytic cell recruitment and VCAM-1 induction was prevented in the presence of the PPAR-gamma antagonist GW9662. Conclusions: Treatment with telmisartan decreases the TNF-α-induced recruitment of monocytic cells and endothelial expression of VCAM-1 in regions of non-uniform shear stress in vitro. This mechanism can contribute to the beneficial pleiotropic effects of telmisartan in atherosclerosis-prone arterial regions.
Abstract: Objectives: This study was designed to determine if a) hyperbaric oxygen increases the tissue oxygenation of free flaps and b) verification of this effect is possible by using a recently validated and innovative method for two-dimensional pO2 measurement (Luminescence lifetime imaging = LLI). Methods: Six patients with a free parascapular flap transplanted to the lower limb received hyperbaric oxygen (HBOT) therapy. The HBOT regimen consisted of treatment over 90 minutes with 100% O2 (FiO2 1.0) at 240 kPa (Marx-Schema). The transcutaneous oxygen partial pressure (ptc O2 ) was measured over the entire flap with the use of…luminescence lifetime imaging (LLI) before and 30, 60, 120 minutes after treatment. The LLI is based on the oxygen dependent quenching of phosphorescence of the indicator dye platinum (II)-octaethyl-porphyrin implemented in a polystyrene sensor foil. Results: In all six free flaps we could find a significant increase of tissue oxygen over the entire flap in form of increased R-values as well as subsequently calculated absolute ptc O2 values over a period of 120 min after hyperbaric therapy. The ptc O2 values increased significantly from 42.59 ± 1.11 Torr before to 81.14 ± 5.95 Torr after hyperbaric treatment (p < 0.001). Even after 2 hours the ptc O2 values were significantly higher (83.45 ± 13.80 Torr) compared with values prior to HBOT (p < 0.006). Conclusions: The findings of this study demonstrated an increase of oxygen supply over the entire flap after hyperbaric oxygen therapy.
Abstract: Background: Free flap transplantation is used more and more frequently in order to cover extensive wound defects. The basic prerequisite for successful flap salvage after flap failure is a short time interval from failure until revision. For this reason many different flap monitoring systems have been tested over the last years. Objective: The aim of the experiment was to detect critical capillary perfusion using contrast enhanced ultrasound. Quantitative analysis should be performed by a special perfusion software (QONTRAST®; Bracco, Italy) appraising digital raw data of contrast enhanced ultrasound (CEUS). Additionally diverse risk factors for free flap transplantation were determined. Methods:…Thirty-one patients were examined after free flap transplantation during the first 72 hours after operation. CEUS was performed with a linear transducer (6–9 MHz, LOGIQ E9/GE) and a bolus injection of 2.4 ml of contrast agent (SonoVue®, Bracco, Italy). Operation and examination were performed by either an experienced plastic surgeon or an experienced ultrasound examiner. Depth dependent capillary perfusion was analysed and quantitative perfusions analysis was performed using the perfusions software QONTRAST® (Bracco, Italy). Eleven revisions had to be performed: 7 due to haematoma and 4 due to superficial necrosis. Results: Reduced capillary perfusion was seen in all 11 complications using CEUS. Significant difference comparing the no complication and the complication group was observed using TTP (time to PEAK) and RBV (regional blood volume) quantitative analysis. Mean RBV was 922.1 ± 150.9 in the no complication and 303.0 ± 53.9 in the complication group (p = 0.001). Mean TTP was 37.6 ± 3.8 in the no complication and 21.3 ± 3.4 in the complication group (p = 0.006). Tendency to higher complication rate was seen in older male patients with vascular or malignant primary disease. Conclusion: In this clinical trial, capillary perfusion after free flap transplantation as well as detection of vascular complications was demonstrated using CEUS. Quantitative perfusions analysis could be performed and flap viability could be assessed easily.
Abstract: Purpose: The objective was to characterize the microcirculation of parathyroid adenomas using contrast-enhanced ultrasound (CEUS) and to evaluate if it can be used for diagnosis and localization of pathologic glands. Patients and methods: Thirty patients with primary hyperparathyroidism scheduled for parathyroidectomy were enrolled. Preoperatively, all patients underwent B-Scan sonography, Colour coded Doppler Sonography (CCDS), Power Doppler (PD) and CEUS. The diagnostic confidence concerning B-Scan, CCDS, PD and CEUS was classified into six grades (0: no adenoma; 5: adenoma). Results: Using CEUS, all adenomatous glands showed a typical dynamic microvascularization. B-Scan showed a mean grade of 2.18, CCDS 2.29, PD 2.33,…CEUS 4.29 (6–9 MHz transducer) and 3.52 (6–15 MHz). The differences between CEUS and conventional sonography were all statistically significant (p < 0.05). CEUS noted a sensitivity of 98.4% and specificity of 98.4% for the detection of adenomatous glands. Conclusion: CEUS facilitates the detection and diagnosis of pathologic parathyroid glands due to their typical microvascularization.