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Experimental and Clinical... Dec 2021Livers procured via donation after cardiac death have produced good outcomes. Some centers use only aortic perfusion; others add portal perfusion.
OBJECTIVES
Livers procured via donation after cardiac death have produced good outcomes. Some centers use only aortic perfusion; others add portal perfusion.
MATERIALS AND METHODS
We report a series of organ procurements in which portal perfusion was performed via cannulation of the splenic vein instead of the inferior mesenteric vein in 4 donors after cardiac death and 2 donors after brain death.
RESULTS
After declaration of death, donors were brought to the operating room and prepared and draped. During procurement, first the aorta was cannulated, and then the atrium or inferior vena cava was opened and perfusion was started.The spleen was mobilized, the splenic vein was dissected out and cannulated, and portal perfusion was performed with 2 L of University of Wisconsin solution. Five liver allografts were transplanted: 3 at our center, and 2 at outside centers. One liver from a donor after cardiac death was declined because of a high fat content. All 5 transplanted grafts showed good initial function; there was no sign of primary nonfunction, and no vascular or biliary complications developed.
CONCLUSIONS
For livers from donors after cardiac death, cannulation of the splenic vein was easier than access via the inferior mesenteric vein. For donors after brain death, we also found this technique was suitable for livers with intra-abdominal adhesions or a small inferior mesenteric vein. Graft outcomes in this series were excellent.
Topics: Adenosine; Allopurinol; Brain Death; Death; Glutathione; Humans; Insulin; Liver; Liver Transplantation; Organ Preservation; Organ Preservation Solutions; Perfusion; Portal Vein; Raffinose; Splenic Vein; Tissue Donors; Tissue and Organ Procurement; Treatment Outcome
PubMed: 34951347
DOI: 10.6002/ect.2021.0212 -
Science Advances Dec 2023Proper placental vascularization is vital for pregnancy outcomes, but assessing it with animal models and human explants has limitations. We introduce a 3D in vitro...
Proper placental vascularization is vital for pregnancy outcomes, but assessing it with animal models and human explants has limitations. We introduce a 3D in vitro model of human placenta terminal villi including fetal mesenchyme and vascular endothelium. By coculturing HUVEC, placental fibroblasts, and pericytes in a macrofluidic chip with a flow reservoir, we generate fully perfusable fetal microvessels. Pressure-driven flow facilitates microvessel growth and remodeling, resulting in early formation of interconnected and lasting placental-like vascular networks. Computational fluid dynamics simulations predict shear forces, which increase microtissue stiffness, decrease diffusivity, and enhance barrier function as shear stress rises. Mass spectrometry analysis reveals enhanced protein expression with flow, including matrix stability regulators, proteins associated with actin dynamics, and cytoskeleton organization. Our model provides a powerful tool for deducing complex in vivo parameters, such as shear stress on developing vascularized placental tissue, and holds promise for unraveling gestational disorders related to the vasculature.
Topics: Animals; Pregnancy; Humans; Female; Placenta; Perfusion; Neovascularization, Pathologic; Coculture Techniques; Microvessels
PubMed: 38134282
DOI: 10.1126/sciadv.adj8540 -
Frontiers in Immunology 2022Normothermic machine perfusion (NMP) allows viability assessment and potential resuscitation of donor livers prior to transplantation. The immunological effect of NMP on...
BACKGROUND
Normothermic machine perfusion (NMP) allows viability assessment and potential resuscitation of donor livers prior to transplantation. The immunological effect of NMP on liver allografts is undetermined, with potential implications on allograft function, rejection outcomes and overall survival. In this study we define the changes in immune profile of human livers during NMP.
METHODS
Six human livers were placed on a NMP device. Tissue and perfusate samples were obtained during cold storage prior to perfusion and at 1, 3, and 6 hours of perfusion. Flow cytometry, immunohistochemistry, and bead-based immunoassays were used to measure leukocyte composition and cytokines in the perfusate and within the liver tissue. Mean values between baseline and time points were compared by Student's t-test.
RESULTS
Within circulating perfusate, significantly increased frequencies of CD4 T cells, B cells and eosinophils were detectable by 1 hour of NMP and continued to increase at 6 hours of perfusion. On the other hand, NK cell frequency significantly decreased by 1 hour of NMP and remained decreased for the duration of perfusion. Within the liver tissue there was significantly increased B cell frequency but decreased neutrophils detectable at 6 hours of NMP. A transient decrease in intermediate monocyte frequency was detectable in liver tissue during the middle of the perfusion run. Overall, no significant differences were detectable in tissue resident T regulatory cells during NMP. Significantly increased levels of pro-inflammatory and anti-inflammatory cytokines were seen following initiation of NMP that continued to rise throughout duration of perfusion.
CONCLUSIONS
Time-dependent dynamic changes are seen in individual leukocyte cell-types within both perfusate and tissue compartments of donor livers during NMP. This suggests a potential role of NMP in altering the immunogenicity of donor livers prior to transplant. These data also provide insights for future work to recondition the intrinsic immune profile of donor livers during NMP prior to transplantation.
Topics: Cytokines; Humans; Liver; Liver Transplantation; Living Donors; Organ Preservation; Perfusion
PubMed: 35720395
DOI: 10.3389/fimmu.2022.788935 -
Seizure Nov 2021Status epilepticus (SE) is a neurological emergency and in particular nonconvulsive SE (NCSE) represents a diagnostic challenge. To improve clinical decision-making,...
INTRODUCTION
Status epilepticus (SE) is a neurological emergency and in particular nonconvulsive SE (NCSE) represents a diagnostic challenge. To improve clinical decision-making, cerebral perfusion-computed tomography (PCT) has been shown as a helpful tool to support the diagnosis of focal NCSE.
MATERIALS AND METHODS
This is a monocentric retrospective study. Among the 602 cases of SE observed between September 2013 and April 2020 we included 21 patients that were studied with PCT. The perfusion maps were first visually analysed then a quantitative analysis (by regions of interest, ROI) was obtained. For each patient, the diagnostic EEG was reviewed and classified in accordance to the Salzburg Criteria for NCSE (SCC) as definite (D-NCSE) and possible (P-NCSE). Finally, we analysed the relationship between PCT and EEG patterns.
RESULTS
Hyper-perfusion was observed in 18 patients (86%), while in the remaining 3 (14%) a normo-perfused pattern was present. Hyper-perfusion was observed in 14 of the D-NCSE group (88%) and in the two patients with a P-NCSE (100%). No one among the patients with a P-NCSE had a thalamic hyper-perfusion, while among the 6 patients with continuous sustained epileptiform discharges > 2.5 Hz (pattern 1 of SCC), 4 (67%) showed cortical plus thalamic hyper-perfusion.
CONCLUSIONS
PCT could facilitate the differential diagnosis and speed-up the diagnostic process of NCSE in emergency situations. Finding cortical multi-lobar hyper-perfusion, especially if present together with homolateral thalamic hyper-perfusion in a patient with an acute-onset of motor/sensory/language deficits is highly suggestive for the presence of NCSE and is particularly related to continuous/sustained ictal patterns.
Topics: Electroencephalography; Humans; Perfusion; Retrospective Studies; Status Epilepticus; Tomography, X-Ray Computed
PubMed: 34391029
DOI: 10.1016/j.seizure.2021.08.002 -
Acta Neuropathologica Communications Sep 2019Perfusing fixatives through the cerebrovascular system is the gold standard approach in animals to prepare brain tissue for spatial biomolecular profiling, circuit... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Perfusing fixatives through the cerebrovascular system is the gold standard approach in animals to prepare brain tissue for spatial biomolecular profiling, circuit tracing, and ultrastructural studies such as connectomics. Translating these discoveries to humans requires examination of postmortem autopsy brain tissue. Yet banked brain tissue is routinely prepared using immersion fixation, which is a significant barrier to optimal preservation of tissue architecture. The challenges involved in adopting perfusion fixation in brain banks and the extent to which it improves histology quality are not well defined.
METHODOLOGY
We searched four databases to identify studies that have performed perfusion fixation in human brain tissue and screened the references of the eligible studies to identify further studies. From the included studies, we extracted data about the methods that they used, as well as any data comparing perfusion fixation to immersion fixation. The protocol was preregistered at the Open Science Framework: https://osf.io/cv3ys/ .
RESULTS
We screened 4489 abstracts, 214 full-text publications, and identified 35 studies that met our inclusion criteria, which collectively reported on the perfusion fixation of 558 human brains. We identified a wide variety of approaches to perfusion fixation, including perfusion fixation of the brain in situ and ex situ, perfusion fixation through different sets of blood vessels, and perfusion fixation with different washout solutions, fixatives, perfusion pressures, and postfixation tissue processing methods. Through a qualitative synthesis of data comparing the outcomes of perfusion and immersion fixation, we found moderate confidence evidence showing that perfusion fixation results in equal or greater subjective histology quality compared to immersion fixation of relatively large volumes of brain tissue, in an equal or shorter amount of time.
CONCLUSIONS
This manuscript serves as a resource for investigators interested in building upon the methods and results of previous research in designing their own perfusion fixation studies in human brains or other large animal brains. We also suggest several future research directions, such as comparing the in situ and ex situ approaches to perfusion fixation, studying the efficacy of different washout solutions, and elucidating the types of brain donors in which perfusion fixation is likely to result in higher fixation quality than immersion fixation.
Topics: Brain; Humans; Perfusion; Tissue Banks; Tissue Fixation
PubMed: 31488214
DOI: 10.1186/s40478-019-0799-y -
The Journal of Surgical Research Feb 2022Machine perfusion is gaining interest as an efficient method of tissue preservation of Vascularized Composite Allografts (VCA). The aim of this study was to develop a...
BACKGROUND
Machine perfusion is gaining interest as an efficient method of tissue preservation of Vascularized Composite Allografts (VCA). The aim of this study was to develop a protocol for ex vivo subnormothermic oxygenated machine perfusion (SNMP) on rodent hindlimbs and to validate our protocol in a heterotopic hindlimb transplant model.
METHODS
In this optimization study we compared three different solutions during 6 h of SNMP (n = 4 per group). Ten control limbs were stored in a preservation solution on Static Cold Storage [SCS]). During SNMP we monitored arterial flowrate, lactate levels, and edema. After SNMP, muscle biopsies were taken for histology examination, and energy charge analysis. We validated the best perfusion protocol in a heterotopic limb transplantation model with 30-d follow up (n = 13). As controls, we transplanted untreated limbs (n = 5) and hindlimbs preserved with either 6 or 24 h of SCS (n = 4 and n = 5).
RESULTS
During SNMP, arterial outflow increased, and lactate clearance decreased in all groups. Total edema was significantly lower in the HBOC-201 group compared to the BSA group (P = 0.005), 4.9 (4.3-6.1) versus 48.8 (39.1-53.2) percentage, but not to the BSA + PEG group (P = 0.19). Energy charge levels of SCS controls decreased 4-fold compared to limbs perfused with acellular oxygen carrier HBOC-201, 0.10 (0.07-0.17) versus 0.46 (0.42-0.49) respectively (P = 0.002).
CONCLUSIONS
Six hours ex vivo SNMP of rodent hindlimbs using an acellular oxygen carrier HBOC-201 results in superior tissue preservation compared to conventional SCS.
Topics: Allografts; Animals; Composite Tissue Allografts; Extremities; Organ Preservation; Oxygen; Perfusion
PubMed: 34670191
DOI: 10.1016/j.jss.2021.09.005 -
Scientific Reports Oct 2020Remote imaging photoplethysmography (iPPG) senses the cardiac pulse in outer skin layers and is responsive to mean arterial pressure and pulse pressure in critically ill...
Remote imaging photoplethysmography (iPPG) senses the cardiac pulse in outer skin layers and is responsive to mean arterial pressure and pulse pressure in critically ill patients. Whether iPPG is sufficiently sensitive to monitor cutaneous perfusion is not known. This study aimed at determining the response of iPPG to changes in cutaneous perfusion measured by Laser speckle imaging (LSI). Thirty-seven volunteers were engaged in a cognitive test known to evoke autonomic nervous activity and a Heat test. Simultaneous measurements of iPPG and LSI were taken at baseline and during cutaneous perfusion challenges. A perfusion index (PI) was calculated to assess iPPG signal strength. The response of iPPG to the challenges and its relation to LSI were determined. PI of iPPG significantly increased in response to autonomic nervous stimuli and to the Heat test by 5.8% (p = 0.005) and 11.1% (p < 0.001), respectively. PI was associated with LSI measures of cutaneous perfusion throughout experiments (p < 0.001). iPPG responses to study task correlated with those of LSI (r = 0.62, p < 0.001) and were comparable among subjects. iPPG is sensitive to autonomic nervous activity in volunteers and is closely associated with cutaneous perfusion.
Topics: Adult; Blood Pressure; Diagnostic Imaging; Female; Heart Rate; Humans; Male; Monitoring, Physiologic; Perfusion; Photoplethysmography; Skin; Volunteers
PubMed: 33020579
DOI: 10.1038/s41598-020-73531-0 -
Transplant International : Official... 2023Pancreas transplantation is the only curative treatment for patients with complicated diabetes, and organ shortage is a common and increasing problem. Strategies to...
Pancreas transplantation is the only curative treatment for patients with complicated diabetes, and organ shortage is a common and increasing problem. Strategies to expand the donor pool are needed, and normothermic perfusion of the pancreas has the potential to test and repair grafts before implantation. Between January 2021 and April 2022, six human pancreases, declined for transplantation or islet isolation, were perfused using a previously established method by our group. All 6 cases were successfully perfused for 4 h, with minimal edema. The mean age of the donors was 44.16 ± 13.8 years. Five grafts were obtained from neurological death donors, and one was obtained from a donation after cardiac death. The mean glucose and lactate levels decreased throughout perfusion and insulin levels increased. All 6 grafts were metabolically active during perfusion and histopathology showed minimal tissue injury and no edema. Human normothermic perfusion of the pancreas is feasible and safe and has the potential to expand the donor pool. Future studies will focus on tests and biomarkers for the assessment of grafts.
Topics: Humans; Adult; Middle Aged; Organ Preservation; Feasibility Studies; Perfusion; Tissue Donors; Pancreas; Allografts
PubMed: 37252614
DOI: 10.3389/ti.2023.10936 -
Critical Care (London, England) Jun 2021In acute respiratory distress syndrome (ARDS), non-ventilated perfused regions coexist with non-perfused ventilated regions within lungs. The number of unmatched regions... (Observational Study)
Observational Study
BACKGROUND
In acute respiratory distress syndrome (ARDS), non-ventilated perfused regions coexist with non-perfused ventilated regions within lungs. The number of unmatched regions might reflect ARDS severity and affect the risk of ventilation-induced lung injury. Despite pathophysiological relevance, unmatched ventilation and perfusion are not routinely assessed at the bedside. The aims of this study were to quantify unmatched ventilation and perfusion at the bedside by electrical impedance tomography (EIT) investigating their association with mortality in patients with ARDS and to explore the effects of positive end-expiratory pressure (PEEP) on unmatched ventilation and perfusion in subgroups of patients with different ARDS severity based on PaO/FiO and compliance.
METHODS
Prospective observational study in 50 patients with mild (36%), moderate (46%), and severe (18%) ARDS under clinical ventilation settings. EIT was applied to measure the regional distribution of ventilation and perfusion using central venous bolus of saline 5% during end-inspiratory pause. We defined unmatched units as the percentage of only ventilated units plus the percentage of only perfused units.
RESULTS
Percentage of unmatched units was significantly higher in non-survivors compared to survivors (32[27-47]% vs. 21[17-27]%, p < 0.001). Percentage of unmatched units was an independent predictor of mortality (OR 1.22, 95% CI 1.07-1.39, p = 0.004) with an area under the ROC curve of 0.88 (95% CI 0.79-0.97, p < 0.001). The percentage of ventilation to the ventral region of the lung was higher than the percentage of ventilation to the dorsal region (32 [27-38]% vs. 18 [13-21]%, p < 0.001), while the opposite was true for perfusion (28 [22-38]% vs. 36 [32-44]%, p < 0.001). Higher percentage of only perfused units was correlated with lower dorsal ventilation (r = - 0.486, p < 0.001) and with lower PaO/FiO ratio (r = - 0.293, p = 0.039).
CONCLUSIONS
EIT allows bedside assessment of unmatched ventilation and perfusion in mechanically ventilated patients with ARDS. Measurement of unmatched units could identify patients at higher risk of death and could guide personalized treatment.
Topics: Adult; Aged; Electric Impedance; Female; Humans; Italy; Male; Middle Aged; Perfusion; Prognosis; Prospective Studies; Respiration, Artificial; Respiratory Distress Syndrome; Simplified Acute Physiology Score
PubMed: 34082795
DOI: 10.1186/s13054-021-03615-4 -
Journal of Visualized Experiments : JoVE Feb 2021Lung histology is often used to investigate the contributions provided by airspace cells during lung homeostasis and disease pathogenesis. However, commonly used...
Lung histology is often used to investigate the contributions provided by airspace cells during lung homeostasis and disease pathogenesis. However, commonly used instillation-based fixation methods can displace airspace cells and mucus into terminal airways and can alter tissue morphology. In comparison, vascular perfusion-fixation techniques are superior at preserving the location and morphology of cells within airspaces and the mucosal lining. However, if positive airway pressure is not simultaneously applied, regions of the lungs may collapse and capillaries may bulge into the alveolar spaces, leading to distortion of the lung anatomy. Herein, we describe an inexpensive method for air-inflation during vascular perfusion-fixation to preserve the morphology and location of airway and alveolar cells and interstitium in murine lungs for downstream histologic studies. Constant air pressure is delivered to the lungs via the trachea from a sealed, air-filled chamber that maintains pressure via an adjustable liquid column while fixative is perfused through the right ventricle.
Topics: Animals; Blood Vessels; Fixatives; Lung; Mice; Perfusion; Pressure; Pulmonary Alveoli
PubMed: 33616116
DOI: 10.3791/62215