Clinical Hemorheology and Microcirculation - Volume 79, issue 1

Authors: Küpper, J.-H. | Krüger-Genge, A. | Jung, F.

Article Type: Editorial

DOI: 10.3233/CH-219100

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 1-2, 2021

Authors: Jung, E.M. | Kammerer, S. | Brandenstein, M. | Putz, F.J. | Stroszczynski, C. | Jung, F.

Article Type: Research Article

Abstract: AIM: To evaluate the possibilities of flow detection using high resolution flow (HR Flow) and Glazing Flow technique in patients with liver parenchymal changes and flow changes in comparison to color-coded Doppler sonography (CCDS). MATERIAL AND METHODS: All examinations were performed using a multi frequency matrix convex probe with high resolution technique (SC6-1U/Resona7, Mindray, Shenzhen, China) by one experienced examiner to evaluate the venous, portal venous and arterial liver flow with digital documentation of the dynamic flow parameters like peak systolic flow, end-diastolic flow and resistance index. For liver parenchymal stiffness changes shear wave elastography was performed with …at least 10 measurements. By two independent readers an elevation was performed to evaluate the image quality and the degree of flow artefacts, from 0 = not available to 5 points with excellent image quality without flow artefacts. RESULTS: All 40 patients (24 men, 16 women, age 27–83 years, mean 56±5 years) showed morphology changes from B-Mode of the liver parenchyma to inhomogeneous tissue with higher stiffness evaluated by the shear wave elastography (1.45 m/s up to 2.79 m/s±1.79 m/s, considering F1 up to F4 fibrosis) and in 15 cases histopathologically proven liver cirrhosis. In 9 cases after non-acute thrombosis flow reduction of the portal vein was the reason for the diameter less than 5 mm. Flow parameters for the venous flow were between 8 cm/s up to 29 cm/s, mean 14±4 cm/s, for the hepatic portal vein 5 cm/s up to 57 cm/s, mean 17±5 cm/s, for the hepatic artery systolic flow between 50 cm/s up to 127±33 cm/s, end-diastolic flow from 22 cm/s up to 47±8 cm/s. Resistance index for the hepatic artery was between 0.41 up to 0.73, mean 0.67±0.25. The image quality for CCDS over all cases was evaluated for CCDS between 1 up to 4. The mean quality was 2.5±0.5, for HR Flow in combination with Glazing Flow 3±0.5, with significant differences for the 2 readers (P  < 0.01). CONCLUSION: Combination of HR Flow with Glazing Flow could be helpful to evaluate morphological und hemodynamic changes of liver arterial flow, portal venous and venous flow. Reduction of flow artefacts in combination with a higher image quality could be helpful for optimizing the digital measurements also for follow up examinations. Show more

Keywords: Liver vascular imaging, high resolution flow (HR), Glazing Flow, imaging quality, artefact reduction

DOI: 10.3233/CH-219102

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 3-17, 2021

Authors: Rio Bartulos, Carolina | Lier, Dennis | Sahl, Harald | Abu-Mugheisib, Mazen | Spreer, Annette | Wiggermann, Philipp

Article Type: Research Article

Abstract: BACKGROUND: Mechanical thrombectomy (MT) is a standard stroke treatment for patients with large vessel occlusions (LVOs). A decisive factor for a successful outcome is, among other things, timely treatment. OBJECTIVE: The objective was to analyze several time points in relation to outcomes and/or surrogate parameters. Furthermore, our data was placed in the context of other clinical trial data. METHODS: We retrospectively evaluated 133 data sets from patients who underwent MT. The correlation of various time periods with parameters, such as the ASPECTS, NIHSS, mRS, and, particularly, the TICI score, was investigated. RESULTS: A correlation …was found for both the NIHSS score at discharge and the TICI score with the time periods of arrival and/or start to groin puncture as well as with arrival to the end of the intervention and the duration of the intervention. CONCLUSIONS: This retrospective study is consistent with large randomized clinical trials investigating stroke management and provides data from daily clinical practice. Show more

Keywords: Acute ischemic stroke, thrombectomy, time to treatment

DOI: 10.3233/CH-219107

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 19-26, 2021

Authors: Brandenstein, M. | Wiesinger, I. | Jung, F. | Stroszczynski, C. | Jung, E.M.

Article Type: Research Article

Abstract: AIM: To improve preoperative diagnostics of solid non-cystic thyroid lesions by using new high-performance ultrasound techniques: optimized B-mode morphology, elastography, Color-Coded Doppler-Sonography (CCDS) and contrast enhanced ultrasound (CEUS) MATERIALS AND METHODS: In 33 cases solid, non-cystic thyroid lesions were rated as TIRADS 3 and up from conventional B-mode examinations. Additional high resolution Power Doppler including HR- and Glazing-Flow as optimized macrovascularization techniques, shear wave elastography and CEUS were performed on these patients by one experienced examiner. For CEUS a bolus of 1–2.4 ml Sulfurhexafluorid microbubbles (SonoVue®, Bracco, Milan, Italy) was injected into a cubital vein and then the distribution …kinetics of the contrast agent were documented from the early arterial phase (10 to 15 seconds after injection) to the late venous phase (5 minutes after injection). Postoperative histopathology was the diagnostic gold standard as it provides the most reliable proof. RESULTS: 33 patients (13 males, 20 females; age 29 –77 years; mean 55 years; SD 13 years) were included in this study. 28 of them had benign regressive thyroid nodules, 3 had adenomas and 4 were diagnosed with carcinomas (3 were histologically identified as papillary thyroid carcinomas, one as a medullary thyroid carcinoma). The volume of the thyroid gland ranged from 6.6 to 401.3 cm2 (mean 72.6±92.0 cm2 ). The adenoma diameters ranged from 9 to 40 mm (mean 22±16 mm) and the carcinoma diameters ranged from 19 to 33 mm (mean 26±6 mm). The 3 adenomas had different echogenicities: One was completely echofree, one was hypoechoic and one isoechoic. The 4 carcinomas however were equally characterized as hypoechoic and echofree. Two of three adenomas and all of the carcinomas showed an incomplete or diffuse margin. Micro-calcifications were found in one adenoma and in every carcinoma. However, no micro-calcifications were observed in cases of benign regressive nodules. Performing shear-wave elastography the adenomas showed lower values than the carcinomas: The tissue velocity of the adenomas ranged from 2.86 m/s to 3.85 m/s (mean 3.32±0.5 m/s) and in carcinomas from 3.89 m/s to 5.66 m/s (mean 4.18±0.3 m/s). Marginal hypervascularization was detected in two adenomas after applying CCDS. One adenoma was hypovascularized. The four carcinomas showed an irregular extreme hypervascularization along their margins as well as an irregular central normo- or hypervascularization in CCDS. The additional HR-Flow helped reducing artefacts. In CEUS the dynamic capillary microvascularization of all carcinomas was very irregular with early enhancement and followed by partial or complete wash-out. In CEUS two adenomas had no wash-out and the other one showed a partial wash-out. CONCLUSION: Using modern multimodal imaging offers new possibilities for the differentiation between benign and malignant thyroid lesions. It is a very important diagnostic tool in addition to the B-Mode TIRADS classification and eases the decision between TIRADS 3, 4 and 5. However, additional multicenter studies are required for more detailed evaluations. Show more

Keywords: Solid thyroid lesions, high-resolution ultrasound, HR-flow, elastography, CEUS, histopathology

DOI: 10.3233/CH-219101

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 27-38, 2021

Authors: Rennert, Janine | Grosse, Jirka | Einspieler, Ingo | Bäumler, Wolf | Stroszczynski, Christian | Jung, Ernst Michael

Article Type: Research Article

Abstract: AIM: To evaluate the effectiveness of complementary imaging of high-resolution ultrasound including CEUS with PET/CT for tissue characterization and tumor detection. MATERIAL AND METHODS: 100 patients were examined with PET/CT and US/CEUS between January 2018 until February 2020. All patients underwent PET/CT followed by selective US/CEUS within 4 weeks. Comparison regarding concordant or diverging findings in PET/CT and US. Analysis of the differences concerning the lesions number of found by PET/CT and US/CEUS or the possibility of a secured diagnosis following ultrasound causing therapeutic changes. RESULTS: Diverging findings regarding the number of liver lesions in PET/CT …and CEUS were found in 35 out of 64 patients (54%). Regarding renal lesions, a more definite diagnosis following ultrasound, causing a change of therapeutic approach, was achieved in 89%. Concordant results in PET/CT and US were found in 83% of patients with splenic and nodal findings. In 78% of patients with increased musculoskeletal or soft tissue tracer uptake, US was able to make a secured diagnosis with therapeutic changes. CONCLUSION: The present results indicate a strong benefit of complementary imaging of PET/CT and selective, high-resolution ultrasound especially in patients with liver, renal and musculoskeletal or soft tissue findings. Show more

Keywords: PET/CT, ultrasound, complementary imaging

DOI: 10.3233/CH-219105

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 39-54, 2021

Authors: Krusche, Cornelius | Rio Bartulos, Carolina | Abu-Mugheisib, Mazen | Haimerl, Michael | Wiggermann, Philipp

Article Type: Research Article

Abstract: BACKGROUND: In clinical practice, decisions often must be made rapidly; therefore, automated software is useful for diagnostic support. Perfusion computed tomography and follow-up evaluation of perfusion data are valuable tools for selecting the optimal recanalization therapy in patients with acute ischemic stroke. OBJECTIVE: This study aimed to compare commercially available software used to evaluate stroke patients prior to thrombectomy. METHODS: The performance of Olea Sphere (OlS) software vs. CT Neuro Perfusion from Syngo (Sy), as well as the electronic Alberta Stroke Program Early Computed Tomography Score (e-ASPECTS) software vs. an experienced radiologist, were compared using descriptive …statistics including significance analysis, Spearman’s correlation, and the Bland-Altman agreement analysis. For this purpose, 43 data sets of patients with stroke symptoms related to the middle cerebral artery territory were retrospectively post-processed with both tools and analyzed. RESULTS: The automatic e-ASPECTS showed high agreement with an expert rater assessment of the ASPECTS. Using OlS and Sy, we compared the parameters for the ischemic core (relative cerebral blood flow), Time to maximum (Tmax) for the penumbra, and the relative mismatch between these two values. Overall, both software tools achieved good agreement, and their respective values correlated well with each other. However, OlS predicted significantly smaller infarct core volumes compared with Sy. CONCLUSIONS: Although the absolute values have a certain degree of variation, both software programs have good agreement with each other. Show more

Keywords: Acute ischemic stroke, computed tomography, perfusion imaging, software comparison

DOI: 10.3233/CH-219106

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 55-63, 2021

Authors: Marschner, Constantin A. | Schwarze, Vincent | Stredele, Regina | Froelich, Matthias F. | Rübenthaler, Johannes | Geyer, Thomas | Clevert, Dirk-André

Article Type: Research Article

Abstract: BACKGROUND: Vesicoureteral reflux (VUR) represents a common pediatric anomaly in children with an upper urinary tract infection (UTI) and is defined as a retrograde flow of urine from the bladder into the upper urinary tract. There are many diagnostic options available, including voiding cystourethrography (VCUG) and contrasted-enhanced urosonography (ceVUS). ceVUS combines a diagnostic tool with a high sensitivity and specificity which, according to previous study results, was even shown to be superior to VCUG. Nevertheless, despite the recommendation of the EFSUMB, the ceVUS has not found a widespread use in clinical diagnostics in Europe yet. MATERIALS AND METHODS: …Between 2016 and 2020, 49 patients with a marked female dominance (n  = 37) were included. The youngest patient had an age of 5 months, the oldest patient 60 years. The contrast agent used in ceVUS was SonoVue ®, a second-generation blood-pool agent. All examinations were performed and interpreted by a single experienced radiologist (EFSUMB Level 3). RESULTS: The 49 patients included in the study showed no adverse effects. 51% of patients (n  = 26) were referred with the initial diagnosis of suspected VUR, while 49% of patients (n  = 23) came for follow-up examination or to rule out recurrence of VUR. The vast majority had at least one febrile urinary tract infection in their recent medical history (n  = 45; 91,8%). CONCLUSION: ceVUS is an examination method with a low risk profile which represents with its high sensitivity and specificity an excellent diagnostic tool in the evaluation of vesicoureteral reflux, especially in consideration of a generally very young patient cohort. Show more

Keywords: Vesicoureteral reflux, contrasted-enhanced urosonography, voiding cystourethrography, safety profile

DOI: 10.3233/CH-219110

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 65-72, 2021

Authors: Senk, Karin | Wilcke, Juliane | Haimerl, Michael | Verloh, Niklas | Rio Bartulos, Carolina | Bäumler, Wolf | Stroszczynski, Christian | Wiggermann, Philipp

Article Type: Research Article

Abstract: BACKGROUND AND OBJECTIVE: Liver function is one of the most important parameters for the outcome of transarterial chemoembolization (TACE). The liver maximum capacity (LiMAx) test is a bedside test that provides a real-time option for liver function testing. The objective of this pilot study was to investigate the suitability of the LiMAX test for predicting the TACE outcome. METHODS: 20 patients with intermediate-stage hepatocellular carcinoma (HCC) received a LiMAx test 24 h pre and post TACE. In addition, laboratory values were collected to determine liver function and model for endstage liver disease (MELD) scores. The success of TACE was …assessed 6 weeks post intervention by morphological imaging tests using modified response evaluation criteria in solid tumors (mRECIST). RESULTS: Patients with an objective response (OR = CR + PR) according to mRECIST post TACE had significantly higher values in the pre-interventional LiMAx test than patients with a non-OR (PD or SD) post TACE (r (14) = 0.62, p  = 0.01). Higher pre-interventional LiMAx values therefore indicate OR. Patients with a disease control (DC = CR + PR + SD) according to mRECIST post TACE had significantly higher values in the pre-interventional LiMAx test than patients with a non-DC (PD) post TACE (r (14) = 0.65, p  = 0.01). Higher pre-interventional LiMAx values therefore indicate DC. The point biserial correlations of LiMAx values pre and post TACE with the outcome OR or DC were descriptively stronger than those of MELD with OR or DC. This suggests that the LiMAx test correlates better with the treatment response than the MELD score. CONCLUSIONS: For the first time, we were able to show in our study that patients who are scheduled for TACE could benefit from a LiMAx test to be able to estimate the benefit of TACE. The higher the pre-interventional LiMAx values, the higher the benefit of TACE. On the other hand, laboratory parameters summarized in the form of the MELD score had significantly less descriptive correlation with the TACE outcome. Show more

Keywords: TACE, LiMAx, HCC, MRECIST, methacetin breath test, liver function, outcome

DOI: 10.3233/CH-219118

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 73-80, 2021

Authors: Burdenski, Thomas | Bressem, Keno K. | Adams, Lisa C. | Grauhan, Nils F. | Niehues, Stefan M.

Article Type: Research Article

Abstract: BACKGROUND: Computed tomographic (CT) imaging in suspected pulmonary artery embolism represents the standard procedure. Studies without iterative reconstruction proved beneficial using increased iodine delivery rate (IDR). This study compares image quality in pulmonary arteries on iteratively reconstructed CT images of patients with suspected pulmonary embolism using different IDR. MATERIAL AND METHODS: 1065 patients were included in the study. Patients in group A (n  = 493) received an iodine concentration of 40 g/100 ml (IDR 1.6 g/s) and patients in group B (n  = 572) an iodine concentration of 35 g/100 ml (IDR 1.4 g/s) at a flow rate of 4 ml/s. A 80-detector spiral CT scanner with …iterative reconstruction was used. We measured mean density values in truncus pulmonalis, both pulmonary arteries and segmental pulmonary arteries. Subjectively, the contrast of apical and basal pulmonary arteries was determined on a 4-point Likert scale. RESULTS: Radiodensity was significantly higher in all measured pulmonary arteries using the increased IDR (p  < 0.001). TP: 483.0 HU vs. 393.4 HU; APD: 452.1 HU vs. 372.1 HU; APS: 448.2 HU vs. 374.4 HU; ASP: 443.9 vs. 374.4 HU. Subjectively assessed contrast enhancement in apical (p  = 0.077) and basal (p  = 0.429) lung sections showed no significant differences. CONCLUSION: Higher IDR improves objective image quality in all patients with significantly higher radiodensities by iterative reconstruction. Subjective contrast of apical and basal lung sections did not differ. The number of non-sufficient scans decreased with high IDR. Show more

Keywords: Computed tomography, pulmonary embolism, contrast media, iodine concentration

DOI: 10.3233/CH-219115

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 81-89, 2021

Authors: Junge, Florian | Konschake, Wolfgang | Haase, Hermann | Jünger, Michael

Article Type: Research Article

Abstract: BACKGROUND: Edema caused by orthostasis is a common clinical picture in the medical and occupational context. Medical compression therapy with compression stockings (CS) is considered a conservative therapeutic standard in edema therapy. The effect of CS on leg discomfort and the increase of the lower leg volume during a standing load still remains questionable. In addition, it is not entirely known whether there is a correlation between volume increase and discomfort in these individuals. METHOD: A timed, controlled standing load of 15 min was conducted by the participants in this non-randomized controlled study to analyze the change in and …correlation between lower leg volume increase and the occurrence of lower leg discomfort under compression therapy. Below-knee CS with an interface pressure of 23–32 mmHg were used. The lower leg volume was measured following previous studies using an optical three-dimensional volume (ml) measurement system, and sensations of discomfort and the urge to move were asked about using a numerical rating scale (NRS) of 0–10. The subjects conducted a leg movement for 15 s immediately after the standing period; the data were collected again subsequently. A correlation was calculated between the lower leg volume and the data regarding the discomfort and urge to move for each participant. The experiments had already been performed as part of a previous study including the same subjects who did not wear CS. The results of the study conducted here were compared with those of the participants who did not wear CS to investigate the effect of the CS. RESULTS: Lower leg volume increased by an average of 27 ml (p  < 0.001) (without CS: by 63 ml) during standing load in the right leg. During the leg movement after standing load, the lower leg volume increased by 5 ml (n.s.). The sensations of discomfort during the orthostasis increased by 2.6 points on the NRS (p  < 0.001) (without CS: by 3.46 points) and decreased by 1.67 points (p  < 0.001) during the leg movement shortly after the standing period. Participants’ urge to move increased by 3.73 points on the NRS (p  < 0.001) (without CS: by 3.47 points) while the participants performed the standing period and decreased by 2.73 points (p  < 0.001) during the final movement exercise. A weakly significant correlation could be demonstrated between the increase in the lower leg volume and the occurrence of discomfort in 6 out of 13 subjects (p  < 0.1), and between the increase in the lower leg volume and the urge to move in 8 out of 15 subjects (p  < 0.1). CONCLUSION: Standing loads and lack of movement lead to an increase in the lower leg volume and sensation of discomfort in venous healthy subjects wearing CS, which are reduced by wearing them (p  < 0.001). A weakly significant mathematical correlation (Pearson’s correlation coefficient) could be shown between the increase in the lower leg volume and the occurrence of the urge to move in 8 out of 15 subjects (p  < 0.1) and between the increase in lower leg volume and the occurrence of leg discomfort in 6 out of 13 subjects (p  < 0.1). Show more

Keywords: Leg complaints, volume measurements, orthostasis, edema, urge to move, healthy volunteers, lack of movement

DOI: 10.3233/CH-219108

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 91-101, 2021

Authors: Gori, T.

Article Type: Research Article

Abstract: The coronary circulation is a complex system in which vascular resistances are determined by an interplay of forces in at least three compartments: the epicardial, the microvascular, and the venous district. Cardiologists, and particularly interventional cardiologists, normallly place the focus of their attention on diseases of the epicardial coronary circulation as possible causes of coronary syndromes and neglect the importance of the other two compartments of coronary circulation. The study of the coronary microcirculation, an increasingly recognized source of ischemia, has long been disregarded, but is witnessing a revival since the (re-)introduction of diagnostic tools in the better equipped catheterization …laboratories. Unfortunately, to date our understanding of coronary microvascular disease remains incomplete and the numerous proposed classifications fail to reflect its complexity. Further, no specific therapy for these disorders is available. The coronary venous circulation is an even more neglected third vascular district. Its role in regulating coronary resistances is almost completely unexplored, but inital evidence suggests that the modulation of venous pressure might help improve coronary perfusion. Coronary sinus interventions are a group of invasive techniques (both surgical and catheter-based) that are designed to treat ischaemic heart disease by increasing coronary venous pressure and therefore redistributing coronary blood flow towards the endocardium. In this review paper, we revise the role of these interventions with particular focus on acute and chronic coronary microvascular disease. Show more

Keywords: Angina, coronary physiology, microcirculation, microvascular disease

DOI: 10.3233/CH-219103

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 103-107, 2021

Authors: Bruno, Raphael Romano | Wernly, Bernhard | Hornemann, Johanna | Flaatten, Hans | FjØlner, Jesper | Artigas, Antonio | Bollen Pinto, Bernardo | Schefold, Joerg C. | Wolff, Georg | Baldia, Philipp Heinrich | Binneboessel, Stephan | Kelm, Malte | Beil, Michael | Sviri, Sigal | van Heerden, Peter Vernon | Szczeklik, Wojciech | Elhadi, Muhammed | Joannidis, Michael | Oeyen, Sandra | Kondili, Eumorfia | Wollborn, Jakob | Marsh, Brian | Andersen, Finn H. | Moreno, Rui | Leaver, Susannah | Boumendil, Ariane | De Lange, Dylan W. | Guidet, Bertrand | Jung, Christian | on behalf of the COVIP study group

Article Type: Research Article

Abstract: PURPOSE Critically ill elderly patients who suffer from Sars-CoV-2 disease are at high risk for organ failure. The modified MELD-XI score has not been evaluated for outcome prediction in these most vulnerable patients. METHODS The Corona Virus disease (COVID19) in Very Elderly Intensive Care Patients study (COVIP, NCT04321265) prospectively recruited patients on intensive care units (ICU), who were = 70 years. Data were collected from March 2020 to February 2021. The MELD-XI score was calculated using the highest serum bilirubin and creatinine on ICU admission. Univariate and multivariable logistic regression analyses were performed to assess associations between the …MELD-XI score and mortality. The primary outcome was 30-day-mortality, the secondary outcomes were ICU- and 3-month-mortality. RESULTS In total, data from 2,993 patients were analyzed. Most patients had a MELD-XI <12 on admission (76%). The patients with MELD-XI = 12 had a significantly higher 30-day-, ICU- and 3-month-mortality (44%vs 64%, and 42%vs. 59%, and 57%vs. 76%, p < 0.001). After adjustment for multiple confounders, MELD-XI = 12 remained significantly associated with 30-day- (aOR 1.572, CI 1.268–1.949, p < 0.001), ICU-, and 3-month-mortality. CONCLUSION In critically ill elderly intensive care patients with COVID-19, the MELD-XI score constitutes a valuable tool for an early outcome prediction. Show more

Keywords: MELD-XI, elderly, intensive care medicine, COVID-19

DOI: 10.3233/CH-219202

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 109-120, 2021

Authors: Saemann, Lars | Großkopf, Anne | Hoorn, Fabio | Veres, Gábor | Guo, Yuxing | Korkmaz-Icöz, Sevil | Karck, Matthias | Simm, Andreas | Wenzel, Folker | Szabó, Gábor

Article Type: Research Article

Abstract: BACKGROUND: Machine perfusion (MP) is a novel method for donor heart preservation. The coronary microvascular function is important for the transplantation outcome. However, current research on MP in heart transplantation focuses mainly on contractile function. OBJECTIVE: We aim to present the application of Laser-Doppler-Flowmetry to investigate coronary microvascular function during MP. Furthermore, we will discuss the importance of microcirculation monitoring for perfusion-associated studies in HTx research. METHODS: Porcine hearts were cardioplegically arrested and harvested (Control group, N = 4). In an ischemia group (N = 5), we induced global ischemia of the animal by the termination of mechanical ventilation before …harvesting. All hearts were mounted on an MP system for blood perfusion. After 90 minutes, we evaluated the effect of coronary perfusion pressures from 20 to 100 mmHg while coronary laser-doppler-flow (LDF) was measured. RESULTS: Ischemic hearts showed a significantly decreased relative LDF compared to control hearts (1.07±0.06 vs. 1.47±0.15; p  = 0.034). In the control group, the coronary flow was significantly lower at 100 mmHg of perfusion pressure than in the ischemia group (895±66 ml vs. 1112±32 ml; p  = 0.016). CONCLUSIONS: Laser-Doppler-Flowmetry is able to reveal coronary microvascular dysfunction during machine perfusion of hearts and is therefore of substantial interest for perfusion-associated research in heart transplantation. Show more

Keywords: Heart transplantation, myocardial microcirculation, coronary microvasculature, machine perfusion, microvascular dysfunction

DOI: 10.3233/CH-219116

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 121-128, 2021

Authors: Greif, G. | Mrowietz, C. | Meyer-Sievers, H. | Ganter, M. | Jung, F. | Hiebl, B.

Article Type: Research Article

Abstract: In human cardiovascular research, sheep in particular are used as a large animal model in addition to pigs. In these animals, medical products, developed and tested for human medical purposes, are almost exclusively used in interventional studies. Therefore, the extent to which platelets from human and ovine blood differ in terms of adherence, aggregation and activation after a 4- or 8-minutes exposure to glass was investigated. Testing was performed with platelet-rich plasma (PRP) and a modified chandler loop-system, with 4- and 8-minute blood-material exposure times corresponding to 20 and 40 test cycles, respectively, through the entire silicone tube loop of …the test system. In sheep and human PRP, contact with the silicone tubing resulted in a decrease in platelet count after 4 minutes and 20 test cycles, respectively. Four more minutes (20 additional test cycles) caused a further decrease of the platelet count only in sheep PRP. When the silicon tube was partly filled with glass beads, these effects were more pronounced and stronger in sheep then in human PRP. The mean platelet volume, which was used as parameter for platelet aggregation, did not change over time in human PRP without glass exposure. With glass exposure in human and sheep PRP the mean platelet volume increased within 40 test cycles, but this increase was stronger in sheep than in human PRP. Regarding activation behavior, the activation markers CD62P and CD63 were detectable only in < 30% (sheep) and < 45% (human) of platelets, whereas after 8 min of glass exposure, the proportion of CD62P+ and CD63+ cells was more increased than before only in sheep. These results indicate that ovine platelets adhere more strongly to glass and show stronger aggregation behavior after glass contact than human platelets, but that ovine and human platelets differ only slightly in activability by glass. Show more

Keywords: Sheep, platelet, activation, platelet volume, CD42a, CD61, CD62P, CD63

DOI: 10.3233/CH-219104

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 129-136, 2021

Authors: Bietar, Bashir | Zhou, Juan | Lehmann, Christian

Article Type: Research Article

Abstract: BACKGROUND: Stroke, traumatic brain injury, or other forms of central nervous system (CNS) injury initiate a local inflammatory response. Compensatory anti-inflammatory pathways are activated to limit secondary damage due to inflammation. The associated release of immunosuppressing neuromodulators can result in system-wide immune dysregulation (CNS injury-induced immune-depression syndrome –CIDS). OBJECTIVE: To establish an experimental stroke model where CIDS can be studied by intravital microscopy (IVM). METHODS: We used the photothrombotic stroke (PTS) model in C57BL/6 mice and studied its effects on peripheral immunity following challenge with lipopolysaccharide (LPS). Leukocyte activation, as well as capillary perfusion of the …microcirculation, were assessed using intestinal intravital microscopy (IVM). RESULTS: PTS caused a significant reduction in the number of adhering leukocytes in submucosal venules of the terminal ileum of mice challenged with LPS compared to LPS-challenged animals without stroke. Leukocyte rolling was also impacted by PTS in the submucosal venules. Following stroke, we also observed decreased mucosal functional capillary density (FCD). CONCLUSIONS: Our results suggest that PTS with subsequent LPS challenge poses as a viable model to further study CIDS using intravital microscopy of the intestinal microcirculation. Show more

Keywords: Stroke, microcirculation, intravital microscopy, photothrombosis, immunodepression

DOI: 10.3233/CH-219109

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 137-147, 2021

Authors: Greif, G. | Mrowietz, C. | Wendt, M. | Jung, F. | Hiebl, B. | Meyer-Sievers, H.

Article Type: Research Article

Abstract: The pig is the most widely used large animal model in Europe, with cardiovascular research being one of the main areas of application. Adequate refinement of interventional studies in this field, meeting the requirements of Russel and Burchs’ 3 R concept, can only be performed if blood-contacting medical devices are hemocompatible. Because most medical devices for cardiovascular interventional procedures are developed for humans they are tested mostly for compatibility with human blood. The aim of this study was therefore to determine whether there are differences in behavior of porcine and human platelets when they come into contact with glass, which was …used as an exemplary thrombogenic material. For this purpose changes of platelet count, platelet volume and platelet expression of the activation markers CD61, CD62P and CD63 were measured using a modified chandler loop-system simulating the fluidic effects of the blood flow. Minipig and human platelets showed significant differences in number and volume, but not in activation after 4–8 min exposure to glass. Show more

Keywords: Pig, minipig, platelet activation, platelet count, platelet volume, FACS, monoclonal antibody, CD42, CD61, CD62P, CD63

DOI: 10.3233/CH-219201

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 149-155, 2021

Authors: Kohl, Cynthia | Aung, Thiha | Haerteis, Silke | Papathemelis, Thomas

Article Type: Research Article

Abstract: BACKGROUND: Breast cancer is the most common malignant tumor in women and highly heterogeneous with a variety of different molecular subtypes. The analysis of the individual tumor biology is necessary to develop a specific and individualized treatment plan for every patient. The chick chorioallantoic membrane (CAM) model, a 3D-in-vivo -tumor-model, could potentially provide a methodology that facilitates the gain of additional information regarding the tumor biology as well as the testing of the tumor’s individual sensitivity to different therapies. OBJECTIVE: The objective was to establish the grafting of different breast cancer primaries onto the CAM for tumor profiling …and the investigation of different parameters. METHODS: Breast cancer primary tissue of different patients was grafted onto the CAM. Subsequently, 3D volume and perfusion measurements were performed during the engraftment period. Histological analyses of the tumors were carried out after the engraftment period. RESULTS: The grafting of the breast cancer primaries onto the CAM was successful. The tumors remained partially vital and displayed angiogenic development on the CAM. CONCLUSIONS: Breast cancer primary material can be grafted onto the CAM and we observed visible and measurable changes of perfusion over time. Show more

Keywords: Breast cancer primary material, breast cancer, CAM model, 3D-in-vivo-tumor-model

DOI: 10.3233/CH-219113

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 157-166, 2021

Authors: Dittfeld, C. | Winkelkotte, M. | Behrens, S. | Schmieder, F. | Jannasch, A. | Matschke, K. | Sonntag, F. | Tugtekin, SM.

Article Type: Research Article

Abstract: BACKGROUND/AIM: Tissue pathogenesis of aortic valve (AV) stenosis is research focus in cardiac surgery. Model limitations of conventional 2D culture of human or porcine valvular interstitial/endothelial cells (VIC/VECs) isolated from aortic valve tissues but also limited ability of (small) animal models to reflect human (patho)physiological situation in AV position raise the need to establish an in vitro setup using AV tissues. Resulting aim is to approximate (patho)physiological conditions in a dynamic pulsatile Microphysiological System (MPS) to culture human and porcine AV tissue with preservation of tissue viability but also defined ECM composition. MATERIALS/METHODS: A tissue incubation chamber …(TIC) was designed to implement human or porcine tissues (3×5 mm2 ) in a dynamic pulsatile culture in conventional cell culture ambience in a MPS. Cell viability assays based on lactate dehydrogenase (LDH)-release or resazurin-conversion were tested for applicability in the system and applied for a culture period of 14 days with interval evaluation of tissue viability on every other day. Resazurin-assay setup was compared in static vs. dynamic culture using varying substance saturation settings (50–300μM), incubation times and tissue masses and was consequently adapted. RESULTS: Sterile dynamic culture of human and porcine AV tissue segments was established at a pulsatile flow rate range of 0.9–13.4μl/s. Implementation of tissues was realized by stitching the material in a thermoplastic polyurethane (TPU)-ring and insertion in the TIC-MPS-system. Culture volume of 2 ml caused LDH dilution not detectable in standard membrane integrity assay setup. Therefore, detection of resazurin-conversion of viable tissue was investigated. Optimal incubation time for viability conversion was determined at two hours at a saturated concentration of 300μM resazurin. Measurement in static conditions was shown to offer comparable results as dynamic condition but allowing optimal handling and TIC sterilization protocols for long term culture. Preliminary results revealed favourable porcine AV tissue viability over a 14 day period confirmed via resazurin-assay comparing statically cultured tissue counterparts. CONCLUSIONS: Human and porcine AV tissue can be dynamically cultured in a TIC-MPS with monitoring of tissue viability using an adapted resazurin-assay setup. Preliminary results reveal advantageous viability of porcine AV tissues after dynamic TIC-MPS culture compared to static control. Show more

Keywords: Aortic valve stenosis, dynamic tissue culture, tissue viability, resazurin reduction, microphysiological system, human aortic valve

DOI: 10.3233/CH-219112

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 167-178, 2021

Authors: Jannasch, Anett | Rix, Jan | Welzel, Cindy | Schackert, Gabriele | Kirsch, Matthias | König, Ulla | Koch, Edmund | Matschke, Klaus | Tugtekin, Sems Malte | Dittfeld, Claudia | Galli, Roberta

Article Type: Research Article

Abstract: BACKGROUND: Heart valves are exposed to a highly dynamic environment and underlie high tensile and shear forces during opening and closing. Therefore, analysis of mechanical performance of novel heart valve bioprostheses materials, like SULEEI-treated bovine pericardium, is essential and usually carried out by uniaxial tensile tests. Nevertheless, major drawbacks are the unidirectional strain, which does not reflect the in vivo condition and the deformation of the sample material. An alternative approach for measurement of biomechanical properties is offered by Brillouin confocal microscopy (BCM), a novel, non-invasive and three-dimensional method based on the interaction of light with acoustic waves. …OBJECTIVE: BCM is a powerful tool to determine viscoelastic tissue properties and is, for the first time, applied to characterize novel biological graft materials, such as SULEEI-treated bovine pericardium. Therefore, the method has to be validated as a non-invasive alternative to conventional uniaxial tensile tests. METHODS: Vibratome sections of SULEEI-treated bovine pericardium (decellularized, riboflavin/UV-cross-linked and low-energy electron irradiated) as well as native and GA-fixed controls (n  = 3) were analyzed by BCM. In addition, uniaxial tensile tests were performed on equivalent tissue samples and Young’s modulus as well as length of toe region were analyzed from stress-strain diagrams. The structure of the extracellular matrix (ECM), especially collagen and elastin, was investigated by multiphoton microscopy (MPM). RESULTS: SULEEI-treated pericardium exhibited a significantly higher Brillouin shift and hence higher tissue stiffness in comparison to native and GA-fixed controls (native: 5.6±0.2 GHz; GA: 5.5±0.1 GHz; SULEEI: 6.3±0.1 GHz; n  = 3, p  < 0.0001). Similarly, a significantly higher Young’s modulus was detected in SULEEI-treated pericardia in comparison to native tissue (native: 30.0±10.4 MPa; GA: 31.8±10.7 MPa; SULEEI: 42.1±7.0 MPa; n  = 3, p  = 0.027). Native pericardia showed wavy and non-directional collagen fibers as well as thin, linear elastin fibers generating a loose matrix. The fibers of GA-fixed and SULEEI-treated pericardium were aligned in one direction, whereat the SULEEI-sample exhibited a much denser matrix. CONCLUSION: BCM is an innovative and non-invasive method to analyze elastic properties of novel pericardial graft materials with special mechanical requirements, like heart valve bioprostheses. Show more

Keywords: Biomechanics, Brillouin confocal microscopy, heart valve prosthesis, Young’s modulus

DOI: 10.3233/CH-219119

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 179-192, 2021

Authors: Krüger-Genge, A. | Jung, C.G.H. | Braune, S. | Harb, K. | Westphal, S. | Klöpzig, S. | Küpper, J.-H. | Jung, F.

Article Type: Research Article

Abstract: Arthrospira platensis (AP ) and some of its derived products have well-established biological activities as antioxidants or as agents to reduce cardiovascular disease risk factors. Furthermore, AP products have gained increasing importance as potential anti-cancer agents. However, the ingredients of the available products vary greatly with the origin, the type of production and processing, which could have significant consequences for their biological effects. Therefore, the composition and biological influence of five distinct AP powders, which were acquired commercially or produced at a public biotechnology institute, were investigated in regard to their endothelialization capacity using a cell impedance- …(CI) based measurement method. The study revealed that the AP composition and especially the influence on HUVEC proliferation differed significantly between the five AP powders up to 109%. Thus, it could be shown that the method used allows the reliable detection of quantitative differences in biological effects of different AP preparations. Show more

Keywords: Arthrospira platensis, spirulina, endothelial cells

DOI: 10.3233/CH-219200

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 193-203, 2021

Authors: Maring, Janita A. | Becker, Matthias | Tung, Wing Tai | Stamm, Christof | Ma, Nan | Lendlein, Andreas

Article Type: Research Article

Abstract: BACKGROUND: Polymeric materials have been widely used as artificial grafts in cardiovascular applications. These polymeric implants can elicit a detrimental innate and adaptive immune response after interacting with peripheral blood. A surface modification with components from extracellular matrices (ECM) may minimize the activation of immune cells from peripheral blood. The aim of this study is to compare the cellular response of blood-born immune cells to the fiber meshes from polyesteretherurethane (PEEUm) and PEEUm with ECM coating (PEEUm + E). MATERIALS AND METHODS: Electrospun PEEUm were used as-is or coated with human cardiac ECM. Different immune cells were isolated form human …peripheral blood. Cytokine release profile from naïve and activated monocytes was assessed. Macrophage polarization and T cell proliferation, as indication of immune response were evaluated. RESULTS: There was no increase in cytokine release (IL-6, TNF-α, and IL-10) from activated monocytes, macrophages and mononuclear cells on PEEUm; neither upon culturing on PEEUm + E. Naïve monocytes showed increased levels of IL-6 and TNF-α, which were not present on PEEUm + E. There was no difference on monocyte derived macrophage polarization towards pro-inflammatory M1 or anti-inflammatory M2 on PEEUm and PEEUm + E. Moreover, T cell proliferation was not increased upon interacting with PEEUm directly. CONCLUSION: As PEEUm only elicits a minimal response from naïve monocytes but not from monocytes, peripheral blood mononuclear cells (PBMCs) or T cells, the slight improvement in response to PEEUm + E might not justify the additional effort of coating with a human ECM. Show more

Keywords: Immune response, cardiovascular, polymer, ECM, cytokine

DOI: 10.3233/CH-219114

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 205-216, 2021

Authors: Xu, Xun | Nie, Yan | Wang, Weiwei | Ullah, Imran | Tung, Wing Tai | Ma, Nan | Lendlein, Andreas

Article Type: Research Article

Abstract: Human induced pluripotent stem cells (hiPSCs) are a promising cell source to generate the patient-specific lung organoid given their superior differentiation potential. However, the current 3D cell culture approach is tedious and time-consuming with a low success rate and high batch-to-batch variability. Here, we explored the establishment of lung bud organoids by systematically adjusting the initial confluence levels and homogeneity of cell distribution. The efficiency of single cell seeding and clump seeding was compared. Instead of the traditional 3D culture, we established a 2.5D organoid culture to enable the direct monitoring of the internal structure via microscopy. It was found …that the cell confluence and distribution prior to induction were two key parameters, which strongly affected hiPSC differentiation trajectories. Lung bud organoids with positive expression of NKX 2.1, in a single-cell seeding group with homogeneously distributed hiPSCs at 70% confluence (SC_70%_hom) or a clump seeding group with heterogeneously distributed cells at 90% confluence (CL_90%_het), can be observed as early as 9 days post induction. These results suggest that a successful lung bud organoid formation with single-cell seeding of hiPSCs requires a moderate confluence and homogeneous distribution of cells, while high confluence would be a prominent factor to promote the lung organoid formation when seeding hiPSCs as clumps. 2.5D organoids generated with defined culture conditions could become a simple, efficient, and valuable tool facilitating drug screening, disease modeling and personalized medicine. Show more

Keywords: Lung organoid, human induced pluripotent stem cell, cell culture

DOI: 10.3233/CH-219111

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 217-230, 2021

Authors: Schulz, Christian | Jung, Friedrich | Küpper, Jan-Heiner

Article Type: Research Article

Abstract: Cell-based in vitro liver models are an important tool in the development and evaluation of new drugs in pharmacological and toxicological drug assessment. Hepatic microsomal enzyme complexes, consisting of cytochrome P450 oxidoreductase (CPR) and cytochrome P450 monooxygenases (CYPs), play a decisive role in catalysing phase-1 biotransformation of pharmaceuticals and xenobiotics. For a comprehensive understanding of the phase-1 biotransformation of drugs, the availability of well-characterized substances for the targeted modulation of in vitro liver models is essential. In this study, we investigated diphenyleneiodonium (DPI) for its ability to inhibit phase-1 enzyme activity and further its toxicological profile in an …in vitro HepG2 cell model with and without recombinant expression of the most important drug metabolization enzyme CYP3A4. Aim of the study was to identify effective DPI concentrations for CPR/CYP activity modulation and potentially associated dose and time dependent hepatotoxic effects. The cells were treated with DPI doses up to 5,000nM (versus vehicle control) for a maximum of 48 h and subsequently examined for CYP3A4 activity as well as various toxicological relevant parameters such as cell morphology, integrity and viability, intracellular ATP level, and proliferation. Concluding, the experiments revealed a time- and concentration-dependent DPI mediated partial and complete inhibition of CYP3A4 activity in CYP3A4 overexpressing HepG2-cells (HepG2-CYP3A4). Other cell functions, including ATP synthesis and consequently the proliferation were negatively affected in both in vitro cell models. Since neither cell integrity nor cell viability were reduced, the effect of DPI in HepG2 can be assessed as cytostatic rather than cytotoxic. Show more

Keywords: Phase-1, biotransformation, CYP, cytochrome P450 monooxygenase, CYP3A4, diphenyleneiodonium, DPI, HepG2, HepG2-CYP3A4, hepatocytes, NADPH-cytochrome P450 oxidoreductase, POR, CPR

DOI: 10.3233/CH-219117

Citation: Clinical Hemorheology and Microcirculation, vol. 79, no. 1, pp. 231-243, 2021