Male-Female Differences in Acute Type B Aortic Dissection.

BACKGROUND: Acute type B aortic dissection is a cardiovascular emergency with considerable mortality and morbidity risk. Male-female differences have been observed in cardiovascular disease; however, literature on type B aortic dissection is scarce. METHODS AND RESULTS: A retrospective cohort study was conducted including all consecutive patients with acute type B aortic dissection between 2007 and 2017 in 4 tertiary hospitals using patient files and questionnaires for late morbidity. In total, 384 patients were included with a follow-up of 6.1 (range, 0.02-14.8) years, of which 41% (n=156) were female. Women presented at an older age than men (67 [interquartile range (IQR), 57-73] versus 62 [IQR, 52-71]; P=0.015). Prior abdominal aortic aneurysm (6% versus 15%; P=0.009), distally extending dissections (71 versus 85%; P=0.001), and clinical malperfusion (18% versus 32%; P=0.002) were less frequently observed in women. Absolute maximal descending aortic diameters were smaller in women (36 [IQR: 33-40] mm versus 39 [IQR, 36-43] mm; P<0.001), while indexed for body surface area diameters were larger in women (20 [IQR, 18-23] mm/m2 versus 19 [IQR, 17-21] mm/m2). No male-female differences were found in treatment choice; however, indications for invasive treatment were different (P<0.001). Early mortality rate was 9.6% in women and 11.8% in men (P=0.60). The 5-year survival was 83% (95% CI, 77-89) for women and 84% (95% CI, 79-89) for men (P=0.90). No male-female differences were observed in late (re)interventions. CONCLUSIONS: No male-female differences were found in management, early or late death, and morbidity in patients presenting with acute type B aortic dissection, despite distinct clinical profiles at presentation. More details on the impact of age and type of intervention are warranted in future studies.

Long Term Health Related Quality of Life After Acute Type B Aortic Dissection: a Cross Sectional Survey Study.

OBJECTIVE: Acute type B aortic dissection (ATBD) is a rare yet serious cardiovascular event that potentially has an impact on health related quality of life (HRQoL). However, long term follow up data on this topic are scarce. This study aimed to review the long term HRQoL among patients treated for ATBD. METHODS: In this multicentre, cross sectional survey study, consecutive treated patients with ATBD between 2007 and 2017 in four referral centres in the Netherlands were retrospectively included and baseline data were collected. Between 2019 and 2021 the 36 Item Short Form Survey (SF-36) was sent to all surviving patients (n = 263) and was compared with validated SF-36 scores in the Dutch general population stratified by age and sex. RESULTS: In total, 144 of 263 surviving patients completed the SF-36 (response rate 55%). Median (IQR) age was 68 (61, 76) years at completion of the questionnaire, and 40% (n = 58) were female. Initial treatment was medical in 55% (n = 79), endovascular in 41% (n = 59), and surgical in 4% (n = 6) of ATBD patients. Median follow up time was 6.1 (range 1.7-13.9; IQR 4.0, 9.0) years. Compared with the general population, patients scored significantly worse on six of eight SF-36 subdomains, particularly physical domains. Apart from bodily pain, there were no substantial differences in HRQoL between male and female ATBD patients. Compared with sex matched normative data, females scored significantly worse on five of eight subdomains, whereas males scored significantly lower on six subdomains. Younger patients aged 41-60 years seemed more severely impaired in HRQoL compared with the age matched general population. Treatment strategy did not influence HRQoL outcomes. Follow up time was associated with better Physical and Mental Component Summary scores. CONCLUSION: Long term HRQoL was impaired in ATBD patients compared with the Dutch general population, especially regarding physical status. This warrants more attention for HRQoL during clinical follow up. Rehabilitation programmes including exercise and physical support might improve HRQoL and increase patients' health understanding.

Differences in local immune cell landscape between Q fever and atherosclerotic abdominal aortic aneurysms identified by multiplex immunohistochemistry.

Background: Chronic Q fever is a zoonosis caused by the bacterium Coxiella burnetii which can manifest as infection of an abdominal aortic aneurysm (AAA). Antibiotic therapy often fails, resulting in severe morbidity and high mortality. Whereas previous studies have focused on inflammatory processes in blood, the aim of this study was to investigate local inflammation in aortic tissue. Methods: Multiplex immunohistochemistry was used to investigate local inflammation in Q fever AAAs compared to atherosclerotic AAAs in aorta tissue specimen. Two six-plex panels were used to study both the innate and adaptive immune systems. Results: Q fever AAAs and atherosclerotic AAAs contained similar numbers of CD68+ macrophages and CD3+ T cells. However, in Q fever AAAs, the number of CD68+CD206+ M2 macrophages was increased, while expression of GM-CSF was decreased compared to atherosclerotic AAAs. Furthermore, Q fever AAAs showed an increase in both the number of CD8+ cytotoxic T cells and CD3+CD8-FoxP3+ regulatory T cells. Finally, Q fever AAAs did not contain any well-defined granulomas. Conclusions: These findings demonstrate that despite the presence of pro-inflammatory effector cells, persistent local infection with C. burnetii is associated with an immune-suppressed microenvironment. Funding: This work was supported by SCAN consortium: European Research Area - CardioVascualar Diseases (ERA-CVD) grant [JTC2017-044] and TTW-NWO open technology grant [STW-14716].

Outcome in Patients after Autologous Femoral Vein Reconstruction for Primary Aortic Infection and Aortic Graft Infection: A Case Series.

BACKGROUND: For surgical treatment of primary aortic infection and aortic graft infection, in situ reconstruction with autologous vein(s) has the lowest rates of re-infection and of graft thrombosis. In this study, we have assessed the outcome after autologous femoral vein reconstruction in patients with aortic (graft) infection and we provide insights into the specific technical surgical considerations of the procedure. METHODS: In this retrospective single-center study, all patients who underwent autologous femoral vein reconstruction because of primary aortic infection or aortic graft infection between January 2012 and January 2020 were included. The primary outcome parameter was 30-day mortality. RESULTS: Twenty-nine patients with autologous femoral vein reconstruction for a primary aortic infection (n = 3) or aortic graft infection (n = 26) were included. An aorto-enteral fistula was detected in 13 patients (49%). Venous reconstruction of the aorta was performed with a single femoral vein in 17 patients (59%), and two femoral veins in 12 patients (41%). Thirty-day mortality was 17%. Relapse of infection occurred in two patients (7%) and no amputations were needed. One year after surgery, only three patients (10%) still needed stockings and after 2 years none of the patients used stockings. CONCLUSIONS: Central aortic reconstruction with femoral veins is a durable solution for primary aortic and aortoiliac graft infections with a low incidence of reinfections, amputations, and venous hypertension.

Acute Effects of Dietary Nitrate on Exercise Tolerance, Muscle Oxygenation, and Cardiovascular Function in Patients With Peripheral Arterial Disease.

Previous studies have used supplements to increase dietary nitrate intake in clinical populations. Little is known about whether effects can also be induced through vegetable consumption. Therefore, the aim of this study was to assess the impact of dietary nitrate, through nitrate-rich vegetables (NRV) and beetroot juice (BRJ) supplementation, on plasma nitrate and nitrite concentrations, exercise tolerance, muscle oxygenation, and cardiovascular function in patients with peripheral arterial disease. In a randomized crossover design, 18 patients with peripheral arterial disease (age: 73 ± 8 years) followed a nitrate intake protocol (∼6.5 mmol) through the consumption of NRV, BRJ, and nitrate-depleted BRJ (placebo). Blood samples were taken, blood pressure and arterial stiffness were measured in fasted state and 150 min after intervention. Each intervention was followed by a maximal walking exercise test to determine claudication onset time and peak walking time. Gastrocnemius oxygenation was measured by near-infrared spectroscopy. Blood samples were taken and blood pressure was measured 10 min after exercise. Mean plasma nitrate and nitrite concentrations increased (nitrate; Time × Intervention interaction; p < .001), with the highest concentrations after BRJ (494 ± 110 µmol/L) compared with NRV (202 ± 89 µmol/L) and placebo (80 ± 19 µmol/L; p < .001). Mean claudication onset time and peak walking time did not differ between NRV (413 ± 187 s and 745 ± 220 s, respectively), BRJ (392 ± 154 s and 746 ± 176 s), and placebo (403 ± 176 s and 696 ± 222 s) (p = .762 and p = .165, respectively). Gastrocnemius oxygenation, blood pressure, and arterial stiffness were not affected by the intervention. NRV and BRJ intake markedly increase plasma nitrate and nitrite, but this does not translate to improved exercise tolerance, muscle oxygenation, and/or cardiovascular function.

The influence of internal iliac artery occlusion after endovascular abdominal aneurysm repair on buttock claudication and erectile dysfunction: a matched case-control study.

BACKGROUND: Buttock claudication (BC) and erectile dysfunction (ED) are well-known complications of intentional occlusion of the internal iliac artery (IIA) in endovascular aneurysm repair (EVAR). The long-term prevalence and impact on the quality of life (QOL) is, however, often not reported. METHODS: We retrospectively identified 347 patients who underwent an EVAR between 2006 and 2016 of which 76 patients (cases) received an intentional occlusion of the IIA. 76 matched controls were found leading to a total of 152 patients. Patient notes were reviewed, a standardized telephonic interview about BC complaints was conducted and questionnaires on QOL (Vascular Quality of Life questionnaire, VascuQol-25), ED (international index of erectile function, IIEF) and walking impairment (walking impairment questionnaire, WIQ) were sent. RESULTS: Mean age of this cohort was 73 years and 89% were males. The short-term incidence of BC in the cases was 71% (N.=20/28) and the long-term incidence 57% (N.=16/28), compared to 35% (N.=8/23) and 26%(N.=6/23) in the controls (P=0.008 and P=0.024), respectively. ED occurs in 96% (N.=22/23) of the cases and in 86% of the controls (N.=18/21) (P=0.262). Cases did not show a significantly lower mean VascuQoL score (4.8) compared to controls (5.5; P=0.081). No differences were observed in WIQ scores between cases (0.58) and controls (0.60; P=0.840). CONCLUSIONS: Intentional occlusion of the IIA increased the incidence of short- and long-term BC but did not affect the prevalence of erectile dysfunction. The impact of IIA occlusion on VascuQoL and WIQ scores was limited and probably not clinically relevant.

Predictors of symptomatic lymphocele after kidney transplantation.

PURPOSE: The development of a symptomatic lymphocele (SL) is a frequent postoperative surgical complication after kidney transplantation. It may lead to pain and discomfort and cause transplant malfunction or even secondary graft loss. A large cohort of renal recipients was investigated to identify the possible risk factors for SL. METHODS: All renal transplant patients of a single centre were retrospectively analysed for SL between January 2010 and December 2017. The SL group was compared to a control group from the same cohort. RESULTS: 45 out of 1003 transplanted patients developed an SL (incidence 4.5%), on average 50 days after kidney transplantation. SLs developed more in older patients, in those with a PD catheter and in ADKDP as primary diagnosis. Surgical predictors for SLs were venous anastomosis on the external iliac vein, concomitant PD catheter removal, perfusion defects, shorter operating time, splint > 7 days, double J stenting, discharge with drain, low initial drain production and ureteral obstruction. Opening of the peritoneum, re-operation for postoperative bleeding and previous nephrectomy seem protective for developing SL. CONCLUSION: We found multiple heterogeneous predictors for SL with a common denominator related to surgical management of the retroperitoneal space, peritoneum and the ureter. Future prospective studies are necessary to evaluate the influence of these variables on the development of SL.

Efficacy of profound versus moderate neuromuscular blockade in enhancing postoperative recovery after laparoscopic donor nephrectomy: A randomised controlled trial.

BACKGROUND: Profound neuromuscular blockade (NMB) during anaesthesia has been shown to reduce postoperative pain scores, when compared with a moderate block. We hypothesised that profound NMB during laparoscopic donor nephrectomy (LDN) could also improve the early quality of recovery after surgery. OBJECTIVES: To compare the effectiveness of profound versus moderate NMB during LDN in enhancing postoperative recovery. DESIGN: A phase IV, double-blinded, randomised controlled trial. SETTING: Multicentre trial, from November 2016 to December 2017. PATIENTS: A total of 101 living kidney donors scheduled for LDN were enrolled, and 96 patients were included in the analyses. INTERVENTIONS: Patients were randomised to receive profound (posttetanic count 1 to 3) or moderate (train-of-four count 1 to 3) neuromuscular block. MAIN OUTCOME MEASURES: The primary outcome was the early quality of recovery at postoperative day 1, measured by the Quality of Recovery-40 Questionnaire. Secondary outcomes were adverse events, postoperative pain, analgesic consumption and length-of-stay. RESULTS: The intention-to-treat analysis did not show a difference with regard to the quality of recovery, pain scores, analgesic consumption and length-of-stay. Less intra-operative adverse events occurred in patients allocated to profound NMB (1/48 versus 6/48). Five patients allocated to a profound NMB received a moderate block and in two patients neuromuscular monitoring failed. The as-treated analysis revealed that pain scores were significantly lower at 6, 24 and 48 h after surgery. Moreover, the quality of recovery was significantly better at postoperative day 2 in patients receiving a profound versus moderate block (179.5 ±â€Š13.6 versus 172.3 ±â€Š19.2). CONCLUSION: Secondary analysis indicates that an adequately maintained profound neuromuscular block improves postoperative pain scores and quality of recovery. As the intention-to-treat analysis did not reveal a difference regarding the primary endpoint, future studies should pursue whether a thoroughly maintained profound NMB during laparoscopy improves relevant patient outcomes. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02838134.

Effectiveness of Heated Sterile Water vs ResoClear® for Prevention of Laparoscopic Lens Fogging in a Randomized Comparative Trial.

BACKGROUND: Laparoscopic surgery may be complicated by visual disturbances, including lens fogging. Several techniques have been developed to prevent laparoscopic lens fogging (LLF). We aim to compare the effectiveness of two commonly available techniques in prevention of LLF: heated sterile water in a thermos flask and ResoClear® impregnation wipes. MATERIALS AND METHODS: In this single-center prospective randomized study, 50 patients underwent an elective laparoscopic donor nephrectomy and were allocated to either heated sterile water or ResoClear® impregnation wipes as the antifogging method. The primary outcome was the number of fogging events during the first 30 minutes of the operation, whereas secondary outcomes were operating time, number of cleaning events because of other causes, cost differences, and assessment of predicting factors for fogging events. RESULTS: In 50 patients, the outcomes were analyzed. The number of fogging events was significantly lower when using heated sterile water (median = 0, interquartile range [IQR]: 0-0) compared to ResoClear® (median 1.0, IQR: 0.5-3.0), p < 0.001. There were no significant differences in operating time, number of cleaning events because of other causes, and costs. No predictors of fogging events were found. CONCLUSION: The use of heated sterile water leads to significantly less fogging events than the use of ResoClear® impregnation wipes, resulting in an improved continuity of the surgery without differences in operating time and costs.

Systematic review and meta-analysis of skin substitutes in the treatment of diabetic foot ulcers: Highlights of a Cochrane systematic review.

Skin substitutes are increasingly used in the treatment of various types of acute and chronic wounds. The aim of this study was to perform a systematic review and meta-analysis to evaluate the effectiveness of skin substitutes on ulcer healing and limb salvage in the treatment of diabetic foot ulcers. Randomized clinical trials were searched and assessed following the methodology of The Cochrane Collaboration. We included 17 trials, totaling 1655 randomized participants. Risk of bias was variable among included trials. Thirteen trials compared the skin substitutes with standard care. The pooled results showed that that skin substitutes can, in addition to standard care, increase the likelihood of achieving complete ulcer closure compared with standard care alone after 6-16 weeks (risk ratio 1.55, 95% confidence interval [CI] 1.30-1.85). Four of the included trials compared two types of skin substitutes but no particular product showed a superior effect over another. Two trials reported on total incidence of lower limb amputations. Pooling the results of these two trials yielded a statistically significantly lower amputation rate among patients treated with skin substitutes (risk ratio 0.43, 95% CI 0.23-0.81), although the absolute risk difference was small (-0.06, 95% CI -0.10 to -0.01). This systematic review provides evidence that skin substitutes can, in addition to standard care, increase the likelihood of achieving complete ulcer closure compared with standard care alone in the treatment of diabetic foot ulcers. However, effectiveness on the long term, including lower limb salvage and recurrence, is currently lacking and cost-effectiveness is unclear.

Skin grafting and tissue replacement for treating foot ulcers in people with diabetes.

BACKGROUND: Foot ulceration is a major problem in people with diabetes and is the leading cause of hospitalisation and limb amputations. Skin grafts and tissue replacements can be used to reconstruct skin defects for people with diabetic foot ulcers in addition to providing them with standard care. Skin substitutes can consist of bioengineered or artificial skin, autografts (taken from the patient), allografts (taken from another person) or xenografts (taken from animals). OBJECTIVES: To determine the benefits and harms of skin grafting and tissue replacement for treating foot ulcers in people with diabetes. SEARCH METHODS: In April 2015 we searched: The Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE and EBSCO CINAHL. We also searched clinical trial registries to identify ongoing studies. We did not apply restrictions to language, date of publication or study setting. SELECTION CRITERIA: Randomised clinical trials (RCTs) of skin grafts or tissue replacements for treating foot ulcers in people with diabetes. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed the quality of the included studies. MAIN RESULTS: We included seventeen studies with a total of 1655 randomised participants in this review. Risk of bias was variable among studies. Blinding of participants, personnel and outcome assessment was not possible in most trials because of obvious differences between the treatments. The lack of a blinded outcome assessor may have caused detection bias when ulcer healing was assessed. However, possible detection bias is hard to prevent due to the nature of the skin replacement products we assessed, and the fact that they are easily recognisable. Strikingly, nearly all studies (15/17) reported industry involvement; at least one of the authors was connected to a commercial organisation or the study was funded by a commercial organisation. In addition, the funnel plot for assessing risk of bias appeared to be asymmetrical; suggesting that small studies with 'negative' results are less likely to be published.Thirteen of the studies included in this review compared a skin graft or tissue replacement with standard care. Four studies compared two grafts or tissue replacements with each other. When we pooled the results of all the individual studies, the skin grafts and tissue replacement products that were used in the trials increased the healing rate of foot ulcers in patients with diabetes compared to standard care (risk ratio (RR) 1.55, 95% confidence interval (CI) 1.30 to 1.85, low quality of evidence). However, the strength of effect was variable depending on the specific product that was used (e.g. EpiFix® RR 11.08, 95% CI 1.69 to 72.82 and OrCel® RR 1.75, 95% CI 0.61 to 5.05). Based on the four included studies that directly compared two products, no specific type of skin graft or tissue replacement showed a superior effect on ulcer healing over another type of skin graft or tissue replacement.Sixteen of the included studies reported on adverse events in various ways. No study reported a statistically significant difference in the occurrence of adverse events between the intervention and the control group.Only two of the included studies reported on total incidence of lower limb amputations. We found fewer amputations in the experimental group compared with the standard care group when we pooled the results of these two studies, although the absolute risk reduction for amputation was small (RR 0.43, 95% CI 0.23 to 0.81; risk difference (RD) -0.06, 95% CI -0.10 to -0.01, very low quality of evidence). AUTHORS' CONCLUSIONS: Based on the studies included in this review, the overall therapeutic effect of skin grafts and tissue replacements used in conjunction with standard care shows an increase in the healing rate of foot ulcers and slightly fewer amputations in people with diabetes compared with standard care alone. However, the data available to us was insufficient for us to draw conclusions on the effectiveness of different types of skin grafts or tissue replacement therapies. In addition, evidence of long term effectiveness is lacking and cost-effectiveness is uncertain.

Why Patencies of Femoropopliteal Bypass Grafts with Distal End-to-End Anastomosis are Comparable with End-to-Side Anastomosis.

OBJECTIVE: Despite the theoretical favourable hemodynamic advantage of end-to-end anastomosis (ETE), femoropopliteal bypasses with distal ETE and end-to-side anastomosis (ETS) have comparable clinical patencies. We therefore studied the effects of different in vivo anastomotic configurations on hemodynamics in geometrically realistic ETE and ETS in vitro flow models to explain this phenomenon. METHODS: Four ETE and two ETS models (30° and 60°) were constructed from in vivo computed tomography angiography data. With flow visualization physiological flow conditions were studied. RESULTS: In ETS, a flow separation and recirculation zone was apparent at anastomotic edges with a shifting stagnation point between them during systole. Secondary flow patterns developed with flow deceleration and reversal. Slight out of axis geometry of all ETE resulted in flow separation and recirculation areas comparable to ETS. Vertical flow patterns were more stable in wider and longer bevelled ETE. CONCLUSION: Primary flow disturbances in ETE are comparable to ETS and are related to the typical sites where myointimal hyperplasia develops. In ETS, reduction of anastomosis angle will diminish flow disturbances. To reduce flow disturbances in ETE, the creation of a bulbous spatulation with resulting axial displacement of graft in relation to recipient artery should be prevented.

Recurrent abdominal complaints caused by a cecal neurofibroma: a case report.

Gastrointestinal involvement of neurofibromatosis type 1 (NF1, Von Recklinghausen's disease) is generally associated with the upper gastrointestinal tract. Abdominal manifestation of NF1 includes several tumors such as malignant peripheral nerve sheath tumors, gastrointestinal stromal tumors and ampulla of vater tumors. However, colonic involvement in NF1 patients is rare. We report a case of a patient presenting with dysphagia, weight loss, intermittent abdominal pain and constipation caused by a single cecal neurofibroma obstructing the ileocecal valve. Also gastrointestinal involvement of the lower tract should be considered in patients with NF1 presenting with abdominal complaints.

[Acute abdominal symptoms in patients with a gastric band]. / Acute buikklachten bij patiënten met een maagband.

Three women aged 32, 35 and 37 years, respectively, presented with upper abdominal symptoms such as pain, nausea and vomiting. Their history revealed that an adjustable silicone gastric band had been implanted for the treatment of obesity one, four and seven years previously. Their symptoms were not immediately recognised as being possible complications of the gastric band and this caused treatment delay. In the first two patients ischaemic lesions were found at laparotomy. Their surgical treatment was successful. The third patient, however, was referred to the surgeon who had placed the gastric band, but she died in the mean time. Lack of recognition of symptoms caused by gastric banding and delay in diagnostic and therapeutic intervention may lead to very serious complications, or even death. Good diagnostic imaging and prompt therapeutic intervention can prevent the progression from herniation of the stomach through the silicone gastric band to irreversible ischaemia and eventually necrosis and perforation.

Expression of glutamine synthetase and carbamoylphosphate synthetase i in a bioartificial liver: markers for the development of zonation in vitro.

BACKGROUND: Mechanisms underlying hepatic zonation are not completely elucidated. In vitro test systems may provide new insights into current hypotheses. In this study, zonally expressed proteins, i.e. glutamine synthetase (GS; pericentral) and carbamoylphosphate synthetase (CPS; periportal), were tested for their expression patterns in the bioartificial liver of the Academic Medical Center (AMC-BAL). METHODS: Distribution and organization of porcine hepatocytes inside the AMC-BAL as well as GS and CPS expression were analyzed (immuno-)histochemically in time. Ten zonally expressed proteins were analyzed by RT-PCR on cell isolate and bioreactor samples. General metabolic and hepatocyte-specific functions were determined as well. RESULTS: Viable hepatocyte layers of approximately 150 microm were observed around gas capillaries, whereas inside the matrix, single cells or small aggregates were present. GS protein and mRNA levels were upregulated in time. GS protein was preferentially expressed in hepatocytes adjacent to oxygen-supplying capillaries and in previously CPS-positive hepatocytes. No shift towards a periportal or pericentral phenotype was observed from RT-PCR analysis. CONCLUSION: Induction of GS expression inside the AMC-BAL is not dependent of (low) oxygen tensions and hepatic nuclear factor 4alpha transcript levels. GS expression might be related to (1) low substrate levels and/or autocrine soluble factors, or (2) to cytoskeleton interactions, putatively associated with the beta-catenin signaling pathway.

Evaluation of a new immortalized human fetal liver cell line (cBAL111) for application in bioartificial liver.

BACKGROUND/AIMS: Clinical use of bioartificial livers (BAL) relies heavily on the development of human liver cell lines. The aim of this study was to assess the potential of the recently developed human fetal liver cell line cBAL111 for application in the AMC-BAL. METHODS: Laboratory-scale AMC-BAL bioreactors were loaded with 20 or 200 million cBAL111 cells and were cultured for 3 days. Parameters for hepatocyte-specific function and general metabolism were determined daily using tests with culture medium or 100% human serum. The bioreactors were also analyzed for mRNA levels of liver-specific genes and histology. RESULTS: cBAL111 eliminated ammonia at a rate up to 49% of that in primary porcine hepatocytes (PPH), despite a low (1.1%) urea production. Transcript levels of glutamine synthetase (GS) were 570% of that in human liver, whereas genes of the urea cycle showed low expression. GS expression was confirmed immunohistochemically, and glutamine was produced by the cells. cBAL111 eliminated galactose (90.1% of PPH) and lidocaine (0.1% of PPH) and produced albumin (6% of PPH). Human serum did not increase function of cBAL111. CONCLUSIONS: cBAL111 showed liver-specific functionality when cultured inside the AMC-BAL and eliminated ammonia mainly by the activity of GS, and not through the urea cycle.

Enhanced oxygen availability improves liver-specific functions of the AMC bioartificial liver.

Long-term culturing of primary porcine hepatocytes (PPH) inside the Academic Medical Center (AMC)-bioartificial liver is characterized by increased anaerobic glycolysis. Recommendations to increase oxygen availability were proposed in a previous numerical study and were experimentally evaluated in this study. Original bioreactors as well as new configuration bioreactors with 2.2-fold thinner nonwoven matrix and 2-fold more capillaries were loaded with PPHs and oxygenated with different gas oxygen pressures resulting in medium pO(2) (pO(2-med)) of either 135-150 mm Hg or 235-250 mm Hg. After 6 days culturing, new configuration bioreactors with pO(2-med )of 250 mm Hg showed significantly reduced anaerobic glycolysis, 60% higher liver-specific functions, and increased transcript levels of five liver-specific genes compared to the standard bioreactor cultures. Changed bioreactor configuration and increasing pO(2-med) contributed equally to these improvements. Histological examination demonstrated small differences in cell organization. In conclusion, higher metabolic stability and liver-specific functionality was achieved by enhanced oxygen availability based on a prior modeling concept.

Time-related analysis of metabolic liver functions, cellular morphology, and gene expression of hepatocytes cultured in the bioartificial liver of the Academic Medical Center in Amsterdam (AMC-BAL).

A comprehensive understanding of the mechanisms that underlie hepatic differentiation inside a bioartificial liver (BAL) device is obtained when functional, histological, and gene expression analyses can be combined. We therefore developed a novel cell-sampling technique that enabled us to analyze adherent hepatocytes inside a BAL device during a 5-day culture period, without the necessity of terminating the culture. Biochemical data showed that hepatocyte-specific functions were relatively stable, despite an increase in glycolytic activity. Quantitative reverse transcriptase polymerase chain reaction analysis of hepatic genes cytochrome p450 3A29, albumin, glutamine synthetase, alpha-1 antitrypsin, and carbamoyl-phosphate synthetase, but also de-differentiation marker pi-class glutathione S transferase showed stable messenger ribonucleic acid (mRNA) levels from day 1 to 5. In contrast, mRNA levels of alpha-fetoprotein, pro- and anti-apoptotic genes Bax-alpha and Bcl-X(L), metabolic genes lactate dehydrogenase and uncoupling protein 2, and cytoskeleton genes alpha- and beta-tubulin and beta-actin increased in 5 days. Histological analysis revealed viable tissue-like structures with adaptation to the in vitro environment. We conclude that hepatocytes show a tendency for de-differentiation shortly after seeding but thereafter remain acceptably differentiated during 5 days of culture. Furthermore, partly impaired mitochondrial function is suggestive for local hypoxic regions and may trigger the observed metabolic changes. Anti-apoptotic activity seems to balance pro-apoptotic activity. This new cell-sampling technique facilitates the analysis of dynamic processes of hepatocyte culture inside a BAL.

Functional and morphological comparison of three primary liver cell types cultured in the AMC bioartificial liver.

The selection of a cell type for bioartificial liver (BAL) systems for the treatment of patients with acute liver failure is in part determined by issues concerning patient safety and cell availability. Consequently, mature porcine hepatocytes (MPHs) have been widely applied in BAL systems. The success of clinical BAL application systems is, however, largely dependent on the functionality and stability of hepatocytes. Therefore, we compared herein the general metabolic and functional activities of MPHs with mature human hepatocytes (MHHs) in the Academic Medical Center (AMC)-BAL during a 7-day culture period. We also tested fetal human hepatocytes (FHHs), since their proliferation capacity is higher than MHHs and their function is increased compared to human liver cell lines. The results showed large differences between the 3 cell types. MHHs eliminated 2-fold more ammonia and produced 3-fold more urea than MPHs, whereas FHHs produced ammonia. Lidocaine elimination of FHHs was 3.5-fold higher than MPHs and 6.6-fold higher than of MHHs. Albumin production was not different between the 3 cell types. MPHs and FHHs became increasingly glycolytic, whereas MHHs remained metabolically stable during the whole culture period. MHHs and MPHs formed tissue-like structures inside the AMC-BAL. In conclusion, we propose that FHHs can be considered as a suitable cell type for pharmacological studies inside a bioreactor. However, we conclude that MHHs are the preferred cell source for loading a BAL device for clinical use, because of their high ammonia eliminating capacity and metabolic stability. MPHs should be considered as the best alternative cell source for BAL application, although their phenotypic instability urges application within 1 or 2 days after loading.