Kenji Yuzawa

Hepatic allograft procurement from non-heart-beating donors : Limits of warm ischemia in porcine liver transplantation

To investigate the tolerance to warm ischemia of liver grafts from non-heart-beating donors, porcine orthotopic liver transplantation was performed using grafts obtained at various periods after cardiac arrest. Graft viability was investigated in relation to changes in hepatic adenine nucleotide metabolism. In donors, livers were divided into four groups according to warm ischemic time after cardiac arrest (group 1: 0 min, n=3; group 2: 30 min, n=3; group 3: 60 min, n=5; group 4: 90 min, n=4). Thereafter, the livers were flushed and preserved for 4 hr using 4 degrees C Euro-Collins solution. After surgery, all of the recipients in groups 1, 2, and 3 survived more than 4 days, except for one pig in group 3 that died of bleeding from an arterial catheter on day 2. By contrast, all of the recipients in group 4 died within 12 hr. The serum glutamic oxaloacetic transaminase concentration at 4 hr after reperfusion of the graft was significantly higher in group 4 (mean+/-SE, 2563+/-556 IU/L) than in groups 1, 2, and 3 (298+/-29 IU/L, 1226+/-222 IU/L, and 1181+/-174 IU/L, respectively). The adenylate energy charge of the liver graft recovered at 1 hr after reperfusion of the graft to 0.852+/-0.013, 0.845+/-0.003, and 0.842+/-0.003 in groups 1, 2, and 3, respectively. The recovery was significantly suppressed in group 4 (0.796+/-0.011). The hepatic adenosine triphosphate concentration also was significantly lower in group 4 compared with the other groups. The present study suggests that liver allografts can be used from non-heart-beating donors subjected to warm ischemia for less than 60 min. Postoperative survival is associated with prompt recovery of the adenylate energy charge of the liver graft.

Transforming growth factor-alpha (TGF alpha)-producing gastric carcinoma with acanthosis nigricans: an endocrine effect of TGF alpha in the pathogenesis of cutaneous paraneoplastic syndrome and epithelial hyperplasia of the esophagus.

A case of well-differentiated adenocarcinoma (Borrmann type 3) of the stomach in a 76-year-old man associated with the typical skin manifestations of acanthosis nigricans and with multiple protruding lesions showing epithelial hyperplasia of the esophagus is reported. The advanced tumor was located in the cardiac region of the stomach, and measured approximately 8cm in diameter, with partial invasion to the esophagus. The associated cutaneous lesions were characterized by hyperpigmentation and by protruding verrucous papules on the torso, head, face, neck, upper extremities, perineum, and inguinal region. Histologically, the protruding skin lesions showed keratinocytes proliferation throughout the epidermis, resulting in diffhyperkeratosis, papillomatosis, and acanthosis of the skin. Immunohistological analysis showed coexpression of transforming growth factor alpha (TGF-a) and epidermal growth factor (EGF) receptors in the tumor from the stomach. It is reasonable to conclude from this evidence that gastric carcinoma cells secrete TGF α in an autocrine for auto-stimulation. EGF receptor expression was also noted on the papillomatous hyperplasia of the cutaneous lesion. Serum level of TGF α, determined by an enzyme-linked immunosorbent assay, was high (144pg/ml; normal, 22.0 ±16pg/ml (Mean±SD)). Serum TGF α abruptly decreased to 49pg/ml on day 7 after the total gastrectomy, and then gradually increased to 77pg/ml within 28 days. Amelioration of the cutaneous lesions and the protruding lesions in the esophagus was observed after surgical resection of the gastric carcinoma. This suggests that the TGF α stimulates the proliferation of keratinocytes involved with EGF receptor. Large amounts of circulating TGF α in the blood over a long period released by the primary tumor seem to act as an endocrine-like mechanism causing epidermal and esophageal epithelial cells to proliferate. There is a possible link in the pathogenesis of the acanthosis nigricans as a cutaneous paraneoplastic syndrome, and epithelial hyperplasia of the esophagus.

Pancreaticoduodenal artery aneurysms associated with celiac axis stenosis due to compression by median arcuate ligament and celiac plexus

Abstract: Celiac axis stenosis is frequently associated with pancreaticoduodenal artery aneurysms. Although the cause of stenosis was not clear in most of the reported cases, compression of the median arcuate ligament of the diaphragm was found to be responsible for the stenosis in 7 of 42 reported cases of this type of aneurysm. We report a case of aneurysm caused by compression of the median arcuate ligament of the diaphragm and celiac plexus. An asymptomatic 43-year-old Japanese man was admitted with a low echoic lesion in the uncus of pancreas. Computed tomographic scan and angiogram revealed stenosis of the celiac axis and two aneurysms in the inferior posterior pancreaticoduodenal artery. The celiac plexus and median arcuate ligament were divided surgically and normal flow was reestablished in the celiac axis. One of the aneurysms was resected and the afferent artery of the other aneurysm was ligated. In the setting of pancreaticoduodenal artery aneurysm associated with celiac axis stenosis, management of stenosis should be considered in addition to local treatment of the aneurysm. In this context, division of median arcuate ligament and celiac plexus or aorto-celiac bypass may normalize the flows in the pancreaticoduodenal arcade and could be effective in preventing aneurysm reformation.

Pancreatic carcinoma: Correlation between E-cadherin and α-catenin expression status and liver metastasis

Dysfunction of the E‐cadherin/catenin‐mediated cell‐cell adhesion system has been associated with invasiveness and poor differentiation of human carcinomas. However, its importance in the genesis of liver metastasis has not been examined sufficiently.

Increased intracranial pressure in a porcine model of fulminant hepatic failure using amatoxin and endotoxin

BACKGROUND/AIMS The purpose of this study was to develop a clinically relevant porcine model of fulminant hepatic failure (FHF) by means of administration of amatoxin and endotoxin. METHODS Pigs were intraportally administered only saline in group 1 (n = 3), 1 microg/kg of lipopolysaccharide (LPS) in group 2 (n = 4), 0.1 mg/kg of alpha-amanitin in group 3 (n = 5), and amanitin plus LPS in group 4 (n = 9). RESULTS All the pigs in groups 1 and 2 survived with minimal changes in liver function tests. In contrast to the 60% mortality in group 3, all the pigs in group 4 died within 96 h, with a significant increase in aspartate transaminase at 24 h (9,757 +/- 2,167 IU/I). In addition, they demonstrated severe metabolic disorders, such as serum lactate accumulation, hypoglycemia, coagulopathy, plasma amino acid imbalance, and hyperammonemia. The intracranial pressure significantly increased to 17.8 +/- 2.5 mmHg immediately before death. Reversal of FHF in these pigs following orthotopic liver transplantation confirmed that the toxicity is liver-specific and that the graft liver is unaffected. CONCLUSIONS This porcine model of FHF induced by a combination of amanitin and LPS will be of much use in the development of new therapies for human FHF.

Effect of lansoprazole and rabeprazole on tacrolimus pharmacokinetics in healthy volunteers with CYP2C19 mutations

The aim of this study was to investigate the effects of the proton pump inhibitors (PPIs), lansoprazole and rabeprazole, on tacrolimus pharmacokinetics in healthy volunteers with mutations in the cytochrome P450 (CYP) 2C19 gene (CYP2C19). An open‐label crossover study was performed with 19 healthy subjects. Tacrolimus (2 mg) was administered orally with and without lansoprazole (30 mg per day for 4 days) or rabeprazole (10 mg per day for 4 days). Blood concentrations of tacrolimus were determined before and 1, 2, 4 and 8 h after dosing. Genotyping for CYP2C19 was conducted by a polymerase chain reaction‐restriction fragment length polymorphism method. Coadministration of lansoprazole significantly decreased the oral tacrolimus clearance, resulting in an increase in the area under the blood concentration‐time curve (AUC0–8) (control vs with lansoprazole: 29.7 ± 3.5 vs 44.1 ± 5.0 ng h mL−1, P<0.05). Large individual variation was observed in the effects of lansorazole on tacrolimus AUC0–8 owing to CYP2C19 genotype status. The percent change for tacrolimus AUC0–8 in subjects with and without CYP2C19 mutant alleles was 81% and 29%, respectively. Coadministration of rabeprazole also increased the mean AUC0–8 of tacrolimus, but the difference was not statistically significant. These observations suggest that drug interaction between tacrolimus and lansoprazole occurs in subjects with higher lansoprazole blood concentrations corresponding to CYP2C19 genetic status. In contrast, rabeprazole has minimal effect on tacrolimus pharmacokinetics regardless of CYP2C19 genotype status.

Endothelin antagonist treatment for successful liver transplantation from non-heart-beating donors.

BACKGROUND With the shortage of cadaveric donors, non-heart-beating donors (NHBDs) are a potential source of liver allografts. However, warm ischemic injury in NHBDs seriously affects the viability of graft liver. Endothelin (ET)-1 has been reported to be involved in the hepatic microcirculatory disturbances after ischemia-reperfusion. METHODS In a porcine orthotopic liver transplantation model, changes in the serum and liver tissue ET-1 concentration were measured and the effects of an ET receptor antagonist, TAK-044, were evaluated. After cardiac arrest of the donors, liver allografts were subjected to 90 min of warm ischemia, flushed, and preserved for 4 hr at 4 degrees C. The pigs were divided into two groups: a control group (no drug treatment) and a drug-treated group, in which donors and recipients were treated with TAK-044 (10 mg/kg body, drip intravenous injection). Both groups had six donor/recipient pairs. RESULTS -The ET-1 concentration in the hepatic venous blood increased after reperfusion of the graft in the control group recipients. ET-1 in the graft liver significantly increased during the cold preservation period. TAK-044 treatment significantly increased recipient 7-day survival rate. After reperfusion of the graft, the concentrations of serum liver enzymes and arterial lactate in the drug-treated group were significantly lower than in the control group. The postoperative increase in portal venous pressure was significantly reduced in the drug-treated group. Measurements of liver enzymes in the washed-out preservation fluid at the time of graft rinsing indicated that TAK-044 treatment of the donors significantly suppressed liver enzyme release during ischemia. CONCLUSIONS These findings indicate TAK-044 treatment has protective effects on postoperative function of hepatic allografts procured from NHBDs.

Prolonged hepatic warm ischemia in non-heart-beating donors: Protective effects of FK506 and a platelet activating factor antagonist in porcine liver transplantation

BACKGROUND Prolonged warm ischemic injury in non-heart-beating donors (NHBDs) significantly affects hepatic allograft function after liver transplantation (LTx). METHODS The effects of FK506 and the platelet activating factor antagonist E5880 on postoperative function of hepatic allografts procured from NHBDs were evaluated in porcine orthotopic LTx. In donors, livers were subjected to 90 minutes of warm ischemia and a subsequent 4-hour cold preservation. Group 1 (n = 6) was the untreated control group. In group 2 (n = 4), donors were pretreated with FK506 (0.3 mg/kg). In group 3 (n = 4), donors and recipients were treated with E5880 (0.3 mg/kg). In group 4 (n = 6), pigs were treated with both FK506 and E5880. RESULTS All of the recipients in group 1 died within 12 hours. In groups 2 and 3, half of the recipients survived more than 12 hours. In group 4, all of the recipients survived more than 2 days (p < 0.01 compared with group 1). The improved survival seen in group 4 was associated with a reduction in the serum concentrations of glutamic oxaloacetic transaminase and lactate, and a restoration of hepatic energy charge. CONCLUSIONS The present study suggests that FK506 and E5880 can improve the function of hepatic allografts subjected to prolonged warm ischemia in NHBDs, and that the protective effects of the two drugs seem to be synergistic.

An ultrasonographic method for detection of Achilles tendon xanthomas in familial hypercholesterolemia

The diagnosis of familial hypercholesterolemia (FH) is frequently made on clinical grounds and detection of tendon xanthomas is crucial for that. In order to clarify whether ultrasonography (US) can be used as a reliable and practical method for detection of Achilles tendon xanthomas in FH, the Achilles tendon thickness in the sagittal section was examined by US in 15 patients with heterozygous FH and 34 normocholesterolemic subjects. US visualized clearly the anterior and posterior borders of the Achilles tendon. The Achilles tendon thickness determined by US correlated with that measured by conventional radiography (r = 0.99). The mean values +/- SD of the Achilles tendon thickness determined by US were 4.5 +/- 0.5 mm in the normal controls and 11.9 +/- 5.1 mm in the patients and the difference was significant (P less than 0.001). In 13 of 15 patients, US visualized thickened Achilles tendons with convex shape in the sagittal section. All the thickened Achilles tendons revealed by US were confirmed by radiography. The data indicate that US can detect Achilles tendons thickened by xanthomas. We conclude that US is a useful aid in the clinical diagnosis of FH.

Mutagenicity of cyclosporine. Induction of sister chromatid exchange in human cells

To examine whether cyclosporine (CsA) has mutagenic potential against human cells, we analyzed sister chromatid exchange (SCE) induction by CsA using human lymphocytes in vitro. SCE frequencies increased significantly in the lymphocytes treated with 1 microgram/ml and 5 micrograms/ml CsA, though the frequencies seemed to be less than one hundredth of those induced by mitomycin C (MMC). The value of induced SCE depended on CsA concentration. This result indicates that CsA has SCE inducibility. The data also suggest that CsA has a mutagenic effect on human lymphocytes.