Continuous Perfusion Research Articles

The Distinct Innate Immune Response of Warm Ischemic Injured Livers during Continuous Normothermic Machine Perfusion.

Although normothermic machine perfusion (NMP) provides superior preservation of liver grafts compared to static cold storage and allows for viability testing of high-risk grafts, its effect on the liver immune compartment remains unclear. We investigated the innate immune response during 6 h of continuous NMP (cNMP) of livers that were directly procured (DP, n = 5) or procured after 60 min warm ischemia (WI, n = 5), followed by 12 h of whole blood (WB) reperfusion. WI livers showed elevated transaminase levels during cNMP but not after WB reperfusion. Perfusate concentrations of TNF-α were lower in WI livers during cNMP and WB reperfusion, whereas IL-8 concentrations did not differ significantly. TGF-β concentrations were higher in WI livers during NMP but not after WB reperfusion, whereas IL-10 concentrations were similar. Endoplasmic stress and apoptotic signaling were increased in WI livers during cNMP but not after WB reperfusion. Additionally, neutrophil mobilization increased to a significantly lesser extent in WI livers at the end of NMP. In conclusion, WI livers exhibit a distinct innate immune response during cNMP compared to DP livers. The cytokine profile shifted towards an anti-inflammatory phenotype during cNMP and WB reperfusion, and pro-apoptotic signaling was stronger during cNMP. During WB reperfusion, livers exhibited a blunted cytokine release, regardless of ischemic damage, supporting the potential reconditioning effect of cNMP.

Applications and Considerations for Microfluidic Systems To Model the Blood-Brain Barrier.

In a myriad of developmental and degenerative brain diseases, characteristic pathological biomarkers are often associated with cerebral blood flow and vasculature. However, the relationship between vascular dysfunction and markers of brain disease is not well-defined. Additionally, it is difficult to deliver effective therapeutics to the brain due to the highly regulated blood-brain barrier (BBB) at the microvasculature interface of the brain. This Review first covers the need for modeling the BBB and the challenges of modeling the BBB. In vitro models of the BBB enable the study of the relationship between vascular dysfunction, BBB function, and disease progression and can serve as a platform to screen therapeutics. In particular, microfluidic-based in vitro BBB models are useful for studying brain vasculature as they support cell culture within the presence of continuous perfusion, which mirrors the in vivo flow and associated stress conditions in the brain. Early microfluidic models of the BBB created the most simplistic models possible that still displayed some functional aspects of the in vivo BBB. Therefore, this Review also discusses the emerging unique ways in which microfluidics in tandem with recent advancements in cell culture, biomaterials, and in vitro modeling can be used to develop more complex and physiologically relevant models of the BBB. Finally, we discuss the current and future state-of-the-art application of microfluidic BBB models for drug development and disease modeling, and the ongoing areas of needed innovation in this field.

Early endovascular intervention for unfavorable remodeling of the thoracic aorta after open surgery for acute DeBakey type I aortic dissection: study protocol for a multicenter, randomized, controlled trial

BackgroundTotal arch replacement with frozen elephant trunk has been developed with promising results for DeBakey type I aortic dissection. However, several problems, such as continuous perfusion of distal false lumen and unfavorable remodeling of distal aorta postoperatively, can seriously affect the long-term outcome. This trial aims to assess the effects of early minimally invasive endovascular repair on distal aortic remodeling and long-term clinical outcomes in patients with dominant false lumen and residual tears in the descending thoracic aorta after total arch replacement and frozen elephant trunk procedure.MethodsThis is a protocol for a two-arm, parallel, multicenter, randomized controlled trial. A total of 154 eligible patients will be recruited from four hospitals in China and randomized on a 1:1 basis either to the experiment group (endovascular repair in addition to routine antihypertensive therapy) or the control group (routine antihypertensive therapy without early surgical treatment). The primary outcome will be the five-year all-cause mortality. The secondary outcomes will include re-intervention, ischemic symptoms, organ dysfunction, and stent-related adverse events.DiscussionIf early minimally invasive endovascular repair could safely and effectively promote distal aortic remodeling and bring favorable long-term outcomes for patients with dominant false lumen and residual tears in the descending thoracic aorta after total arch replacement and frozen elephant trunk technique, it would improve the treatment strategy for DeBakey type I aortic dissection.Trial registrationChinese Clinical Trial Registry, CHiCTR2000030050. Registered on 11 March 2020.

Standardized assessment of vascular reconstruction kernels in photon-counting CT angiographies of the leg using a continuous extracorporeal perfusion model

This study evaluated the influence of different vascular reconstruction kernels on the image quality of CT angiographies of the lower extremity runoff using a 1st-generation photon-counting-detector CT (PCD-CT) compared with dose-matched examinations on a 3rd-generation energy-integrating-detector CT (EID-CT). Inducing continuous extracorporeal perfusion in a human cadaveric model, we performed CT angiographies of eight upper leg arterial runoffs with radiation dose-equivalent 120 kVp acquisition protocols (CTDIvol 5 mGy). Reconstructions were executed with different vascular kernels, matching the individual modulation transfer functions between scanners. Signal-to-noise-ratios (SNR) and contrast-to-noise-ratios (CNR) were computed to assess objective image quality. Six radiologists evaluated image quality subjectively using a forced-choice pairwise comparison tool. Interrater agreement was determined by calculating Kendall’s concordance coefficient (W). The intraluminal attenuation of PCD-CT images was significantly higher than of EID-CT (414.7 ± 27.3 HU vs. 329.3 ± 24.5 HU; p < 0.001). Using comparable kernels, image noise with PCD-CT was significantly lower than with EID-CT (p ≤ 0.044). Correspondingly, SNR and CNR were approximately twofold higher for PCD-CT (p < 0.001). Increasing the spatial frequency for PCD-CT reconstructions by one level resulted in similar metrics compared to EID-CT (CNRfat; EID-CT Bv49: 21.7 ± 3.7 versus PCD-CT Bv60: 21.4 ± 3.5). Overall image quality of PCD-CTA achieved ratings superior to EID-CTA irrespective of the used reconstruction kernels (best: PCD-CT Bv60; worst: EID-CT Bv40; p < 0.001). Interrater agreement was good (W = 0.78). Concluding, PCD-CT offers superior intraluminal attenuation, SNR, and CNR compared to EID-CT in angiographies of the upper leg arterial runoff. Combined with improved subjective image quality, PCD-CT facilitates the use of sharper convolution kernels and ultimately bears the potential of improved vascular structure assessability.

Open arch—my way! Branch first continuous perfusion arch repair (BF-CPAR)

We herein describe our technique of “branch first continuous perfusion arch repair (BF-CPAR)” which does away with both cerebral circulatory arrest and the need fordeep hypothermia. We use this technique for all aortic surgeries including for type A acute aortic dissections.

Non-invasive intradialytic percutaneous perfusion monitoring: a view to the heart through the skin.

The life-sustaining treatment of hemodialysis (HD) induces recurrent and cumulative systemic circulatory stress resulting in cardiovascular injury. These recurrent insults compound preexisting cardiovascular sequalae leading to the development of myocardial injury and resulting in extremely high morbidity/mortality. This is largely a consequence of challenged microcirculatory flow within the myocardium (evidenced by detailed imaging-based studies). Currently, monitoring during HD is performed at the macrovascular level. Non-invasive monitoring of organ perfusion would allow the detection and therapeutic amelioration of this pathophysiological response to HD. Non-invasive percutaneous perfusion monitoring of the skin (using photoplethysmography-PPG) has been shown to be predictive of HD-induced myocardial stunning (a consequence of segmental ischemia). In this study, we extended these observations to include a dynamic assessment of skin perfusion during HD compared with directly measured myocardial perfusion during dialysis and cardiac contractile function. We evaluated the intradialytic microcirculatory response in 12 patients receiving conventional HD treatments using continuous percutaneous perfusion monitoring throughout HD. Cardiac echocardiography was performed prior to the initiation of HD, and again at peak-HD stress, to assess the development of regional wall motion abnormalities (RWMAs). Myocardial perfusion imaging was obtained at the same timepoints (pre-HD and peak-HD stress), utilizing intravenous administered contrast and a computerized tomography (CT)-based method. Intradialytic changes in pulse strength (derived from PPG) were compared with the development of HD-induced RWMAs (indicative of myocardial stunning) and changes in myocardial perfusion. We found an association between the lowest pulse strength reduction (PPG) and the development of RWMAs (p = 0.03) and also with changes in global myocardial perfusion (CT) (p = 0.05). Ultrafiltration rate (mL/kg/hour) was a significant driver of HD-induced circulatory stress [(associated with the greatest pulse strength reduction (p = 0.01), a reduction in global myocardial perfusion (p = 0.001), and the development of RWMAs (p = 0.03)]. Percutaneous perfusion monitoring using PPG is a useful method of assessing intradialytic hemodynamic stability and HD-induced circulatory stress. The information generated at the microcirculatory level of the skin is reflective of direct measures of myocardial perfusion and the development of HD-induced myocardial stunning. This approach for the detection and management of HD-induced cardiac injury warrants additional evaluation.

Vascularized hiPSC-derived 3D cardiac microtissue on chip.

Functional vasculature is essential for delivering nutrients, oxygen, and cells to the heart and removing waste products. Here, we developed an invitro vascularized human cardiac microtissue (MT) model based on human induced pluripotent stem cells (hiPSCs) in a microfluidic organ-on-chip by coculturing hiPSC-derived, pre-vascularized, cardiac MTs with vascular cells within a fibrin hydrogel. We showed that vascular networks spontaneously formed in and around these MTs and were lumenized and interconnected through anastomosis. Anastomosis was fluid flow dependent: continuous perfusion increased vessel density and thus enhanced the formation of the hybrid vessels. Vascularization further improved endothelial cell (EC)-cardiomyocyte communication via EC-derived paracrine factors, such as nitric oxide, and resulted in an enhanced inflammatory response. The platform sets the stage for studies on how organ-specific EC barriers respond to drugs or inflammatory stimuli.

Targeting Cellular Senescence in Organ Transplantation.

Targeting Cellular Senescence in Organ Transplantation.

Estimación de la perfusión de hígado e íleon terminal con microesferas coloreadas, comparando asistencias mecánicas circulatorias de flujo continuo y pulsátil

ObjectiveTo estimate blood flow in the small intestine and liver by administration of coloured microspheres in the left atrium, comparing this estimate with continuous flow perfusion and pulsatile flow, in order to confirm or reject hypoperfusion and hypoxia in these organs attributed to loss of pulse amplitude as the cause of Heyde's syndrome. Material and methodTwenty-two minipig pigs of both sexes weighing 29.5±9.6kg were implanted with 11 continuous and 11 pulsatile mechanical circulatory assist devices were implanted in 22 minipig. Haemodynamic and analytic parameter were measured. Liver and terminal ileum blood perfusión was estimated by administration of stained microspheres previus to circulatory support, at 30minutes of full assist and at 30minutes of partial assist. ResultsData were reported as percent of estimated perfusion at baseline. The study was performed by analysis of variance for repeated measures with a significance α of 0.05. In the liver, type of assistance (total or partial), type of pump (continuous or pulsatile) and the interaction between the 2had the following statistical significance: 0.518. 0.364 and 0.237 respectively. In the terminal ileum the results were: 0.264. 0.193 and 0.141.Analytically significant differences were observed in bilirubin level related to the continuous flow pump, as well as pH and urea. ConclusionsWe observed no significant differences in the estimation of perfusion in ileum and liver when comparing continuous flow and pulsatile flow CMA.

Optimized operation of a controlled stirred tank reactor system for the production of mesenchymal stromal cells and their extracellular vesicles.

The therapeutic effects of human mesenchymal stromal cells (MSC) have been attributed mostly to their paracrine activity, exerted through small-secreted extracellular vesicles (EVs) rather than their engraftment into injured tissues. Currently, the production of MSC-derived EVs (MSC-EVs) is performed in laborious static culture systems with limited manufacturing capacity using serum-containing media. In this work, a serum-/xenogeneic-free microcarrier-based culture system was successfully established for bone marrow-derived MSC cultivation and MSC-EV production using a 2 l-scale controlled stirred tank reactor (STR) operated under fed-batch (FB) or fed-batch combined with continuous perfusion (FB/CP). Overall, maximal cell numbers of (3.0 ± 0.12) × 108 and (5.3 ± 0.32) × 108 were attained at Days 8 and 12 for FB and FB/CP cultures, respectively, and MSC(M) expanded under both conditions retained their immunophenotype. MSC-EVs were identified in the conditioned medium collected from all STR cultures by transmission electron microscopy, and EV protein markers were successfully identified by Western blot analysis. Overall, no significant differences were observed between EVs isolated from MSC expanded in STR operated under the two feeding approaches. EV mean sizes of 163 ± 5.27 nm and 162 ± 4.44 nm (p > 0.05) and concentrations of (2.4 ± 0.35) × 1011 EVs/mL and (3.0 ± 0.48) × 1011 EVs/mL (p > 0.05) were estimated by nanoparticle tracking analysis for FB and FB/CP cultures, respectively. The STR-based platform optimized herein represents a major contribution towardthe development of human MSC- and MSC-EV-based products as promising therapeutic agents for Regenerative Medicine settings.

PULM8: Morphologic And Functional Assessment Of Breathing Lungs In Normothermic Ex-Situ Preservation

Background: Continuous ex-situ machine perfusion has been proposed as an alternative and superior method of donor lungs preservation compared to cold static storage especially during the transport time. The emergence of cardiac ex situ machine perfusion not only facilitates the use of donor lung through the avoidance of potentially damaging ischemia during graft storage, it also opens new horizons for more sensitive monitoring of graft quality in the transplant field, and morphologic-functional assessments. Methods: Twenty-five domestic adult pigs, weighing 93.1±13.1kg were selected for this study. Until pulmonectomy, all pigs received Principles of Laboratory Animal Care. The pig lung were cannulated, and then connected to the Portable System for Normothermic Ex-Situ Lung Preservation (our made). In the Lung Preservation System (HPS), oxygenated blood is perfused by a centrifugal pump into the pulmonary artery and ventilation occurs. After the end of experiment, (6-14 hour) pig lung is disconnected. The pig isolated lung was connected to hemofiltration while in the system and applied in the HPS in order to protect and improve donor lung function. Ex-Situ Lung Perfusion process was accompanied with morphologic-functional assessments such as bronchoscopy, computerized tomography. Results: Mean (SD) ischemic time was 26.2 (±5.3) min. Mean ex vivo perfusion time was 560 (±110) min. All isolated lungs had normal ventilation parameters. All isolated lung had stable perfusion, biochemical and histological characteristics in the perfusion system. Conclusion: Normothermic Ex-Situ Lungs Perfusion provides more physiologic and reproducible approach to sustain the isolated organs.

Dynamics of Ex Vivo Mesenchymal Stromal Cell Potency under Continuous Perfusion.

Mesenchymal stromal cells (MSCs) are a candidate for cell immunotherapy due to potent immunomodulatory activity found in their secretome. Though studies on their secreted substances have been reported, the time dynamics of MSC potency remain unclear. Herein, we report on the dynamics of MSC secretome potency in an ex vivo hollow fiber bioreactor using a continuous perfusion cell culture system that fractionated MSC-secreted factors over time. Time-resolved fractions of MSC-conditioned media were evaluated for potency by incubation with activated immune cells. Three studies were designed to characterize MSC potency under: (1) basal conditions, (2) in situ activation, and (3) pre-licensing. Results indicate that the MSC secretome is most potent in suppressing lymphocyte proliferation during the first 24 h and is further stabilized when MSCs are prelicensed with a cocktail of pro-inflammatory cytokines, IFNγ, TNFα, and IL-1β. The evaluation of temporal cell potency using this integrated bioreactor system can be useful in informing strategies to maximize MSC potency, minimize side effects, and allow greater control for the duration of ex vivo administration approaches.

Continuous extracorporeal femoral perfusion model for intravascular ultrasound, computed tomography and digital subtraction angiography.

We developed a novel human cadaveric perfusion model with continuous extracorporeal femoral perfusion suitable for performing intra-individual comparison studies, training of interventional procedures and preclinical testing of endovascular devices. Objective of this study was to introduce the techniques and evaluate the feasibility for realistic computed tomography angiography (CTA), digital subtraction angiography (DSA) including vascular interventions, and intravascular ultrasound (IVUS). The establishment of the extracorporeal perfusion was attempted using one formalin-fixed and five fresh-frozen human cadavers. In all specimens, the common femoral and popliteal arteries were prepared, introducer sheaths inserted, and perfusion established by a peristaltic pump. Subsequently, we performed CTA and bilateral DSA in five cadavers and IVUS on both legs of four donors. Examination time without unintentional interruption was measured both with and without non-contrast planning CT. Percutaneous transluminal angioplasty and stenting was performed by two interventional radiologists on nine extremities (five donors) using a broad spectrum of different intravascular devices. The perfusion of the upper leg arteries was successfully established in all fresh-frozen but not in the formalin-fixed cadaver. The experimental setup generated a stable circulation in each procedure (ten upper legs) for a period of more than six hours. Images acquired with CT, DSA and IVUS offered a realistic impression and enabled the sufficient visualization of all examined vessel segments. Arterial cannulating, percutaneous transluminal angioplasty as well as stent deployment were feasible in a way that is comparable to a vascular intervention in vivo. The perfusion model allowed for introduction and testing of previously not used devices. The continuous femoral perfusion model can be established with moderate effort, works stable, and is utilizable for medical imaging of the peripheral arterial system using CTA, DSA and IVUS. Therefore, it appears suitable for research studies, developing skills in interventional procedures and testing of new or unfamiliar vascular devices.

Manejo de la analgesia en la pancreatitis aguda. Resultados de una encuesta nacional

IntroductionAcute pancreatitis is one of the main reasons for digestive admissions. Adequate pain treatment is crucial in its management. However, there are hardly any descriptions of the analgesic guidelines used in our setting. MethodsOn-line survey on analgesic management in acute pancreatitis, aimed at attending physicians and residents practising in Spain. ResultsTwo hundred and nine physicians from 88 centres responded to the survey. Ninety percent were specialists in gastrointestinal medicine and 69% worked in a tertiary centre. The majority (64.4%) do not routinely use scales to measure pain. When choosing a drug, experience in its use was the most important factor. The most commonly prescribed initial treatments are: combination of paracetamol and metamizole (53.5%), paracetamol alone (19.1%) and metamizole alone (17.4%). As rescue: meperidine (54.8%), tramadol (17.8%), morphine chloride (17.8%) and metamizole (11.5%). Continuous perfusion is used in 8.2% of initial treatments. Physicians with >10 years of service use more metamizole as monotherapy (50%), while residents and attending physicians with <10 years of service prescribe it in combination with paracetamol (85%). If progression is needed, morphine chloride and meperidine are mainly used. The speciality of the respondent, the size of the work centre and the unit/service where the patients were admitted did not influence the analgesia prescribed. Satisfaction with pain management reached 7.8/10 (SD 0.98). ConclusionIn our setting, metamizole and paracetamol are the most commonly used analgesics as initial pain treatment in acute pancreatitis, and meperidine is the most commonly used rescue analgesic.

Technical comparison of continuous versus intermittent perfusion computed tomography computed tomography scans of the human pancreas.

Pancreatic perfusion computed tomography (CT) imaging is increasingly used for neoplastic grading, predicting prognosis, and evaluating the response to therapy. To optimize the clinical pancreatic CT perfusion imaging methods, we evaluated 2 different CT scanning protocols concerning pancreas perfusion parameters. A retrospective study was conducted on 40 patients who underwent whole pancreas CT perfusion scanning in The First Affiliated Hospital of Zhengzhou University. Of these 40 patients, 20 patients in group A underwent continuous perfusion scanning, while 20 patients in group B underwent intermittent perfusion scanning. For group A, continuous axial scanning was performed 25 times, and the total scan time was 50 s. For group B, arterial phase helical perfusion scanning was performed 8 times, and then venous phase helical perfusion scanning was performed 15 times, with a total scan time of 64.6 to 70.0 s. A comprehensive list of perfusion parameters between different parts of the pancreas and the 2 groups were compared. The effective radiation dose for the 2 scanning methods was analyzed. The parameter of the mean slope of increase (MSI) at different pancreatic parts in group A differed (P=0.028). The pancreas head had the lowest value, and the tail had the highest (about a 20% difference). In group A compared to group B, the blood volume of the pancreatic head was smaller (15.256±2.925 vs. 16.953±3.602), the positive enhanced integral was smaller (0.307±0.050 vs. 0.344±0.060) and the permeability surface was larger (34.205±9. 612 vs. 24.377±8.413); the blood volume of the pancreatic neck was smaller (13.940±2.691 vs. 17.173±3.918), the positive enhanced integral was smaller (0.304±0.088 vs. 0.361±0.051) and the permeability surface was larger (34.898±11.592 vs. 25. 794±8.149); the blood volume of the pancreatic body was smaller (16.142±4.006 vs. 18.401±2.513), the positive enhanced integral was smaller (0.305±0.093 vs. 0.342±0.048) and the permeability surface was larger (28.861±10.448 vs. 22.158±6. 017); the blood volume of the pancreatic tail was smaller (16.446±3.709 vs. 17.374±3.781), the positive enhanced integral was smaller (0.304±0.057 vs. 0.350±0.073) and the permeability surface was larger (27.823±8.228 vs. 21.509±7.768) (P<0.05). The effective radiation dose in the intermittent scan mode was slightly lower at 16.657±2.259 mSv than in the continuous scan mode (17.973±3.698 mSv). Different CT scanning intervals had a significant influence on whole pancreas blood volume, permeability surface, and positive enhanced integral. These demonstrate the high sensitivity of intermittent perfusion scanning for identifying perfusion abnormalities. Therefore, for the diagnosis of pancreatic diseases, intermittent pancreatic CT perfusion may be more advantageous.

The role of Cola nitida on gastric acid secretion and its mechanism of action in male Wistar rats

This study investigated the effect of an aqueous extract of Cola nitida (AECN) and decaffeinated (DECAF) extract of kolanut on gastric acid secretion and its mechanism of action in rats. Previous reporters only speculated that the biological effect of kolanut in causing gastric acid secretion could be ascribed to its caffeine content, also the mechanism is not fully elucidated. In addition, none of the previous reporters has investigated the effect of decaffeinated kolanut extract on gastric acid secretion. Sixty (60) male adult Wistar rats divided into twelve groups of five rats each were used for this study. Groups 1 and 2 received normal saline orally and intravenously respectively at a dose of (1 ml/kg), 3 and 4 received 25 mg/kg of (AECN) orally and intravenously respectively, group 5 received (100mg/kg) AECN orally, groups 6 and 7 received 25mg/kg of (DECAF) both orally and intravenously respectively, group 8 received 100mg/kg of DECAF orally, groups 9 and 10 were pre-treated with cimetidine 12 μmoles/kg intravenously followed by 25 mg/kg AECN and DECAF respectively, groups 11 and 12 were pre-treated with i.v atropine (0.2 mg/kg) followed by 25 mg/kg of AECN and DECAF respectively. Gastric acid secretion was determined by continuous perfusion of rats' stomachs under urethane anesthesia. Data collected were expressed as mean ± SEM. Statistical significance at P≤0.05 was determined using Student’s t-test analysis. The oral administration of AECN (25mg/kg and 100mg/kg) and i.v AECN (25mg/kg) caused a significant increase (P≤0.05) in gastric acid secretion (GAS) with pronounced effect than DECAF group. The oral administration of 25mg/kg and 100mg/kg of DECAF and intravenous administration of (25mg/kg) DECAF caused a significant increase in gastric acid secretion. The administration of cimetidine and atropine significantly reduced gastric acid secretion. In conclusion, aqueous extract of Cola nitida and decaffeinated kolanut extract exert significant gastric acid secretion in this study. Also, the mechanisms exhibited by kolanut in stimulating gastric acid secretion in this study could be attributed to stimulating both the histaminergic H2 and cholinergic (Muscarinic M3) receptors since cimetidine and atropine blocked/reduced its effect. This research work was self-funded. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

First Multicenter Clinical Trial on Machine Perfusion Preservation for Marginal Donor Kidney Transplantation in Japan

Machine perfusion has not been widely used because of its low demand in Japan; however, we believe its advantages may increase the number of organ transplants. Here, we report the first clinical trial of machine perfusion for kidney transplantation in Japan. We used the CMP-X08 perfusion device (Chuo-Seiko Co, Ltd, Asahikawa, Hokkaido, Japan) to preserve the donated organs. The flow rate, perfusion pressure, renal resistance, and temperature were monitored during continuous hypothermic perfusion. From August 2020 to the present, 13 cases of perfusion-preserved kidney transplantation have been performed. Of these, ten and 3 cases were performed using organs donated after brain death (DBD) and cardiac death (DCD), respectively. The average age of the recipients was 55.9 ± 7.3 (45-66) years. The average dialysis period was 14.8 ± 8.4 (0-26) years. The donor's final creatinine level before organ retrieval was 1.58 ± 1.0 (0.46-3.07) mg/dL. The warm ischemic times of the 3 DCD donors were 3, 12, and 18 minutes. The average total ischemic time was 12.0 ± 3.7 (7.17-19.88) hours. The average MP time was 140 (60-240) minutes. A total of 7 cases had delayed graft function. The best creatinine level during hospitalization was 1.17 ± 0.43 (0.71-1.85) mg/dL. There were no primary non-functional cases, and perfusion preservation was safely performed in all cases. Therefore, we present this report as the first clinical trial on machine perfusion for kidney transplantation from marginal donors with DBD and DCD in Japan.

Photon-Counting Versus Energy-Integrating Detector CT Angiography of the Lower Extremity in a Human Cadaveric Model With Continuous Extracorporeal Perfusion.

Detailed visualization of the arterial runoff is mandatory for the assessment of peripheral arterial occlusive disease. This study aims to compare the performance of a first-generation photon-counting detector computed tomography (PCD-CT) to a third-generation energy-integrating detector CT (EID-CT). Computed tomography angiographies of 8 upper leg arterial runoffs were performed on human cadaveric models with continuous extracorporeal perfusion. For both PCD-CT and EID-CT, radiation dose-equivalent 120 kVp acquisition protocols (low-/medium-/high-dose: CTDI Vol = 3/5/10 mGy) were used. All scans were performed with standard collimation (PCD-CT: 144 × 0.4 mm; EID-CT: 96 × 0.6 mm), a pitch factor of 0.4, and a gantry rotation time of 1.0 second. Reformatting of data included the use of comparable vascular kernels (Bv 48/49), a slice thickness and increment of 1.0 mm, and a field of view of 150 × 150 mm. Eight radiologists evaluated image quality independently using a browser-based pairwise forced-choice comparison setup. Kendall concordance coefficient ( W ) was calculated to estimate interrater agreement. Signal-to-noise ratio and contrast-to-noise ratio (CNR) were compared based on 1-way analyses of variance and linear regression analysis. Low-dose PCD-CT achieved superior signal-to-noise ratio/CNR values compared with high-dose EID-CT ( P < 0.001). Linear regression analysis suggested that an EID-CT scan with a CTDI Vol of at least 15.5 mGy was required to match the CNR value of low-dose PCD-CT. Intraluminal contrast attenuation was higher in PCD-CT than EID-CT, irrespective of dose level (415.0 ± 31.9 HU vs 329.2 ± 29.4 HU; P < 0.001). Subjective image quality of low-dose PCD-CT was considered superior to high-dose EID-CT ( P < 0.001). Interrater agreement was high ( W = 0.989). Using cadaveric models with continuous extracorporeal perfusion allows for intraindividual image quality comparisons between PCD-CT and EID-CT on variable dose levels. With superior luminal contrast attenuation and denoising in angiographies of the peripheral arterial runoff, PCD-CT displayed potential for radiation saving of up to 83% compared with EID-CT.

Investigating Cardiac Metabolism in the Isolated Perfused Mouse Heart with Hyperpolarized [1-13C]Pyruvate and 13C/31P NMR Spectroscopy.

Metabolism is the basis of important processes in cellular life. Characterizing how metabolic networks function in living tissues provides crucial information for understanding the mechanism of diseases and designing treatments. In this work, we describe procedures and methodologies for studying in-cell metabolic activity in a retrogradely perfused mouse heart in real-time. The heart was isolated in situ,in conjunction with cardiac arrest to minimize the myocardial ischemia and was perfused inside a nuclear magnetic resonance (NMR) spectrometer. While in the spectrometer and under continuous perfusion, hyperpolarized [1-13C]pyruvate was administered to the heart, and the subsequent hyperpolarized [1-13C]lactate and [13C]bicarbonate production rates served to determine, in real-time, the rates of lactate dehydrogenase and pyruvate dehydrogenase production. This metabolic activity of hyperpolarized [1-13C]pyruvate was quantified with NMR spectroscopy in a model free-manner using the product selective saturating-excitations acquisition approach. 31P spectroscopy was applied in between the hyperpolarized acquisitions to monitor the cardiac energetics and pH. This system is uniquely useful for studying metabolic activity in the healthy and diseased mouse heart.

Abstract 2886: Investigation of tumor-intrinsic activated Wnt/B-catenin signaling in immune avoidance of HCC

Abstract Background: Recent evidence have indicated several tumor-intrinsic oncogene pathways in T cell exclusion and immune evasion of cancers . In hepatocellular carcinoma (HCC), Wnt/β-catenin (CTNNB1) signaling activation is highly prevalent and has been reported to be associated with an immune avoided tumor microenvironment. ICG-001 is a small molecule inhibitor that prevents β-catenin from binding to cyclic AMP response element-binding protein (CBP) by competitively binding itself to CBP. The inhibition of CBP/β-catenin selectively induces apoptosis in transformed cells and have shown tumor suppressive effects in several cancers. Aim: This study aims to investigate the role of tumor-intrinsic Wnt/β-catenin pathway in controlling the expression of chemoattractants in HCC that influence immune cell migration into the tumor site. Methods: We established a syngeneic C57BL/6 mouse model using a hepatoma murine Hepa1-6 isogenic cell line to allow us to interrogate how gain-of-function CTNNB1 mutation (S45P) affects immune surveillance and response to ICG-001 in HCC. The mice were divided into two groups and were subcutaneously injected with either Hepa1-6 vector (n=29) or Hepa1-6 CTNNB1 (S45P) (n=29). At day 6, each group were subdivided into two treatment groups: ICG-001 and untreated. The effect of ICG-001 on immune infiltrates was investigated by Opal multiplex fluorescent immunohistochemistry (IHC) in formalin-fixed, paraffin-embedded (FFPE) tissues. Results: Untreated mice bearing CTNNB1 (S45P) HCCs (n=15) showed larger tumor growth in comparison to their vector controls (n=14), suggesting CTNNB1 (S45P) conferred a more aggressive clone. After a week of ICG-001 treatment by continuous osmotic pump perfusion, 42.9% (6/14) of CTNNB1 (S45P) mice showed a positive response to ICG-001, where a tumor regressed volume was indicated in 4 mice and stable disease in 2 mice. Progressive disease with continuous tumor growth, on the other hand, was shown in all untreated mice. Multiplex fluorescent IHC of tumors obtained from ICG-001 treated CTNNB1 (S45P) mice showed an increased influx of M1 macrophage and CD8 T cells in the tumor site compared to an immune avoidance phenotype in untreated controls. Accordingly, our vector control group did exhibit response to ICG-001 when compared to their respective untreated groups. Based on these findings, it is plausible that CTNNB1 activation impairs the expression of chemoattractant in HCC, and prevents immune cell migration into the tumor site. Consequently, we further examined tumor tissues for chemokine expressions and found higher levels of CXCL9, CXCL10 and CXCL11 in ICG-001 treated CTNNB1 (S45P) when compared to their untreated control groups. In conclusion, our results suggested Wnt/β-catenin activation plays a role in immune evasion and contribution to a “cold” immune tumor microenvironment in HCC. Citation Format: Aikha Melissa Go Wong, Alissa Michelle Go Wong, Loucia KY Can, Joseph Kwong, Anthony WH Chan, Jinna Chen, Michael Kahn, Nathalie Wong. Investigation of tumor-intrinsic activated Wnt/B-catenin signaling in immune avoidance of HCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2886.