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Frontiers in Immunology 2024Primary graft dysfunction (PGD) is a common complication after lung transplantation. A plethora of contributing factors are known and assessment of donor lung function... (Review)
Review
Primary graft dysfunction (PGD) is a common complication after lung transplantation. A plethora of contributing factors are known and assessment of donor lung function prior to organ retrieval is mandatory for determination of lung quality. Specialized centers increasingly perform ex vivo lung perfusion (EVLP) to further assess lung functionality and improve and extend lung preservation with the aim to increase lung utilization. EVLP can be performed following different protocols. The impact of the individual EVLP parameters on PGD development, organ function and postoperative outcome remains to be fully investigated. The variables relate to the engineering and function of the respective perfusion devices, such as the type of pump used, functional, like ventilation modes or physiological (e.g. perfusion solutions). This review reflects on the individual technical and fluid components relevant to EVLP and their respective impact on inflammatory response and outcome. We discuss key components of EVLP protocols and options for further improvement of EVLP in regard to PGD. This review offers an overview of available options for centers establishing an EVLP program and for researchers looking for ways to adapt existing protocols.
Topics: Humans; Lung Injury; Lung; Perfusion; Lung Transplantation; Tissue Donors
PubMed: 38510260
DOI: 10.3389/fimmu.2024.1358153 -
NMR in Biomedicine Oct 2019Because of the spatial and temporal heterogeneities of cancers, technologies to investigate cancer cells and the consequences of their interactions with abnormal... (Review)
Review
Because of the spatial and temporal heterogeneities of cancers, technologies to investigate cancer cells and the consequences of their interactions with abnormal physiological environments, such as hypoxia and acidic extracellular pH, with stromal cells, and with the extracellular matrix, under controlled conditions, are valuable to gain insights into the functioning of cancers. These insights can lead to an understanding of why cancers invade and metastasize, and identify effective treatment strategies. Here we have provided an overview of the applications of MRI/MRS/MRSI to investigate intact perfused cancer cells, their metabolism and invasion, and their interactions with stromal cells and the extracellular matrix.
Topics: Cell Communication; Humans; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Neoplasm Invasiveness; Neoplasms; Perfusion; Stromal Cells
PubMed: 30693605
DOI: 10.1002/nbm.4053 -
Methods in Molecular Biology (Clifton,... 2022Human tissue-engineered blood vessels (TEBVs) that exhibit vasoactivity can be used to test drug toxicity, modulate pro-inflammatory cytokines, and model disease states...
Human tissue-engineered blood vessels (TEBVs) that exhibit vasoactivity can be used to test drug toxicity, modulate pro-inflammatory cytokines, and model disease states in vitro. We developed a novel device to fabricate arteriole-scale human endothelialized TEBVs in situ with smaller volumes and higher throughput than previously reported. Both primary and induced pluripotent stem cell (iPSC)-derived cells can be used. Four collagen TEBVs with 600μm inner diameter and 2.9 mm outer diameter are fabricated by pipetting a solution of collagen and medial cells into a three-layer acrylic mold. After gelation, the TEBVs are released from the mold and dehydrated. After suturing the TEBVs in place and changing the mold parts to form a perfusion chamber, the TEBVs are endothelialized in situ, and then media is perfused through the lumen. By removing 90% of the water after gelation, the TEBVs become mechanically strong enough for perfusion at the physiological shear stress of 0.4 Pa within 24 h of fabrication and maintain function for at least 5 weeks.
Topics: Arterioles; Blood Vessels; Collagen; Humans; Induced Pluripotent Stem Cells; Perfusion; Tissue Engineering
PubMed: 34591300
DOI: 10.1007/978-1-0716-1708-3_7 -
Scandinavian Journal of Trauma,... Dec 2023Selective aortic arch perfusion (SAAP) is a novel endovascular technique that combines thoracic aortic occlusion with extracorporeal perfusion of the brain and heart....
BACKGROUND
Selective aortic arch perfusion (SAAP) is a novel endovascular technique that combines thoracic aortic occlusion with extracorporeal perfusion of the brain and heart. SAAP may have a role in both haemorrhagic shock and in cardiac arrest due to coronary ischaemia. Despite promising animal studies, no data is available that describes SAAP in humans. The primary aim of this study was to assess the feasibility of selective aortic arch perfusion in humans. The secondary aim of the study was to assess the feasibility of achieving direct coronary artery access via the SAAP catheter as a potential conduit for salvage percutaneous coronary intervention.
METHODS
Using perfused human cadavers, a prototype SAAP catheter was inserted into the descending aorta under fluoroscopic guidance via a standard femoral percutaneous access device. The catheter balloon was inflated and the aortic arch perfused with radio-opaque contrast. The coronary arteries were cannulated through the SAAP catheter.
RESULTS
The procedure was conducted four times. During the first two trials the SAAP catheter was passed rapidly and without incident to the intended descending aortic landing zone and aortic arch perfusion was successfully delivered via the device. The SAAP catheter balloon failed on the third trial. On the fourth trial the left coronary system was cannulated using a 5Fr coronary guiding catheter through the central SAAP catheter lumen.
CONCLUSIONS
For the first time using a perfused cadaveric model we have demonstrated that a SAAP catheter can be easily and safely inserted and SAAP can be achieved using conventional endovascular techniques. The SAAP catheter allowed successful access to the proximal aorta and permitted retrograde perfusion of the coronary and cerebral circulation.
Topics: Humans; Aorta; Aorta, Thoracic; Heart Arrest; Perfusion; Shock, Hemorrhagic; Feasibility Studies
PubMed: 38087352
DOI: 10.1186/s13049-023-01148-z -
The Journal of Thoracic and... Feb 2021
Topics: Adsorption; Extracorporeal Circulation; Humans; Lung; Perfusion; Seasons
PubMed: 31959447
DOI: 10.1016/j.jtcvs.2019.12.012 -
American Journal of Veterinary Research Feb 2020To evaluate the feasibility of contrast-enhanced CT for assessment of pancreatic perfusion in healthy dogs.
OBJECTIVE
To evaluate the feasibility of contrast-enhanced CT for assessment of pancreatic perfusion in healthy dogs.
ANIMALS
6 healthy purpose-bred female Treeing Walker Coonhounds.
PROCEDURES
Contrast-enhanced CT of the cranial part of the abdomen was performed with 3-mm slice thickness. Postprocessing computer software designed for evaluation of human patients was used to calculate perfusion data for the pancreas and liver by use of 3-mm and reformatted 6-mm slices. Differences in perfusion variables between the pancreas and liver and differences in liver-specific data of interest were evaluated with the Friedman test.
RESULTS
Multiple pancreatic perfusion variables were determined, including perfusion, peak enhancement index, time to peak enhancement, and blood volume. The same variables as well as arterial, portal, and total perfusion and hepatic perfusion index were determined for the liver. Values for 6-mm slices appeared similar to those for 3-mm slices. The liver had significantly greater median perfusion and peak enhancement index, compared with the pancreas.
CONCLUSIONS AND CLINICAL RELEVANCE
Measurement of pancreatic perfusion with contrast-enhanced CT was feasible in this group of dogs. Hepatic arterial and pancreatic perfusion values were similar to previously published findings for dogs, but hepatic portal and hepatic total perfusion measurements were not. These discrepancies might have been attributable to physiologic differences between dogs and people and related limitations of the CT software intended for evaluation of human patients. Further research is warranted to assess reliability of perfusion variables and applicability of the method for assessment of canine patients with pancreatic abnormalities.
Topics: Animals; Contrast Media; Dogs; Female; Humans; Liver; Pancreas; Perfusion; Reproducibility of Results; Tomography, X-Ray Computed
PubMed: 31985282
DOI: 10.2460/ajvr.81.2.131 -
Physiological Reports Mar 2021
Topics: Animals; Extracellular Matrix; Perfusion; Tissue Scaffolds
PubMed: 33769707
DOI: 10.14814/phy2.14804 -
Journal of Applied Physiology... Nov 2021In recent years, it has become common to experiment with ex vivo perfused lungs for organ transplantation and to attempt regenerative pulmonary engineering using...
In recent years, it has become common to experiment with ex vivo perfused lungs for organ transplantation and to attempt regenerative pulmonary engineering using decellularized lung matrices. However, our understanding of the physiology of ex vivo organ perfusion is imperfect; it is not currently well understood how decreasing microvascular barrier affects the perfusion of pulmonary parenchyma. In addition, protocols for lung perfusion and organ culture fluid-handling are far from standardized, with widespread variation on both basic methods and on ideally controlled parameters. To address both of these deficits, a robust, noninvasive, and mechanistic model is needed which is able to predict microvascular resistance and permeability in perfused lungs while providing insight into capillary recruitment. Although validated mathematical models exist for fluid flow in native pulmonary tissue, previous models generally assume minimal intravascular leak from artery to vein and do not assess capillary bed recruitment. Such models are difficult to apply to both ex vivo lung perfusions, in which edema can develop over time and microvessels can become blocked, and to decellularized ex vivo organomimetic cultures, in which microvascular recruitment is variable and arterially perfused fluid enters into the alveolar space. Here, we develop a mathematical model of pulmonary microvascular fluid flow which is applicable in both instances, and we apply our model to data from native, decellularized, and regenerating lungs under ex vivo perfusion. The results provide substantial insight into microvascular pressure-flow mechanics, while producing previously unknown output values for tissue-specific capillary-alveolar hydraulic conductivity, microvascular recruitment, and total organ barrier resistance. We present a validated model of pulmonary microvascular fluid mechanics and apply this model to study the effects of increased capillary permeability in decellularized and regenerating lungs. We find that decellularization alters microvascular steady-state mechanics and that re-endothelialization partially rescues key biologic parameters. The described model provides powerful insight into intraorgan microvascular dynamics and may be used to guide regenerative engineering experiments. We include all data and derivations necessary to replicate this work.
Topics: Capillaries; Lung; Microvessels; Perfusion
PubMed: 34554016
DOI: 10.1152/japplphysiol.00286.2020 -
Sensors (Basel, Switzerland) Oct 2020The advent of 3D-printing technologies has had a significant effect on the development of medical and biological devices. Perfusion chambers are widely used for...
The advent of 3D-printing technologies has had a significant effect on the development of medical and biological devices. Perfusion chambers are widely used for live-cell imaging in cell biology research; however, air-bubble invasion is a pervasive problem in perfusion systems. Although 3D printing allows the rapid fabrication of millifluidic and microfluidic devices with high resolution, little has been reported on 3D-printed fluidic devices with bubble trapping systems. Herein, we present a 3D-printed millifluidic cartridge system with bent and flat tapered flow channels for preventing air-bubble invasion, irrespective of bubble volume and without the need for additional bubble-removing devices. This system realizes bubble-free perfusion with a user-friendly interface and no-time-penalty manufacturing processes. We demonstrated the bubble removal capability of the cartridge by continually introducing air bubbles with different volumes during the calcium imaging of Sf21 cells expressing insect odorant receptors. Calcium imaging was conducted using a low-magnification objective lens to show the versatility of the cartridge for wide-area observation. We verified that the cartridge could be used as a chemical reaction chamber by conducting protein staining experiments. Our cartridge system is advantageous for a wide range of cell-based bioassays and bioanalytical studies, and can be easily integrated into portable biosensors.
Topics: Cells; Diagnostic Imaging; Lab-On-A-Chip Devices; Perfusion; Printing, Three-Dimensional
PubMed: 33053875
DOI: 10.3390/s20205779 -
BMC Veterinary Research May 2020Perfusion-weighted imaging is only scarcely used in veterinary medicine. The exact reasons are unclear. One reason might be the typically high costs of the software...
BACKGROUND
Perfusion-weighted imaging is only scarcely used in veterinary medicine. The exact reasons are unclear. One reason might be the typically high costs of the software packages for image analysis. In addition, a great variability concerning available programs makes it hard to compare results between different studies. Moreover, these algorithms are tuned for their usage in human medicine and often difficult to adapt to veterinary studies. In order to address these issues, our aim is to deliver a free open source package for calculating quantitative perfusion parameters. We develop an "R package" calculating mean transit time, cerebral blood flow and cerebral blood volume from data obtained with freely imaging software (OsiriX Light®). We hope that the free availability, in combination with the fact that the underlying algorithm is open and adaptable, makes it easier for scientists in veterinary medicine to use, compare and adapt perfusion-weighted imaging analysis. In order to demonstrate the usage of our software package, we reviewed previously acquired perfusion-weighted images from a group of eight purpose-breed healthy beagle dogs and twelve client-owned dogs with idiopathic epilepsy. In order to obtain the data needed for our algorithm, the following steps were performed: First, regions of interest (ROI) were drawn around different, previously reported, brain regions and the middle cerebral artery. Second, a ROI enhancement curve was generated for each ROI using a freely available PlugIn. Third, the signal intensity curves were exported as a comma-separated-value file. These files constitute the input to our software package, which then calculates the PWI parameters.
RESULTS
We used our software package to re-assess perfusion weighted images from two previous studies. The clinical results were similar, showing a significant increase in the mean transit time and a significant decrease in cerebral blood flow for diseased dogs.
CONCLUSION
We provide an "R package" for computing the main perfusion parameters from measurements taken with standard imaging software and describe in detail how to obtain these measurements. We hope that our contribution enables users in veterinary medicine to easily obtain perfusion parameters using standard Open Source software in a standard, adaptable and comparable way.
Topics: Algorithms; Animals; Brain; Cerebrovascular Circulation; Dog Diseases; Dogs; Epilepsy; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Perfusion; Software
PubMed: 32423403
DOI: 10.1186/s12917-020-02352-0