Biomedical subjects

H Fujii

Publications and source records attributed to H Fujii.

At least 181 records · Page 10Linked to original sources

PubMed2000

Antiplatelet and anticancer isothiocyanates in Japanese domestic horseradish, Wasabi.

6-Methylsulfinylhexyl isothiocyanate (MS-ITC) was isolated from wasabi (Wasabia japonica, Japanese domestic horseradish) as a potential inhibitor of human platelet aggregation in vitro through our extensive screening of vegetables and fruits. In the course of an another screening for the induction of glutathione S-transferase (GST) activity in RL34 cells, MS-ITC was inadvertently isolated from wasabi as a potential inducer of GST. MS-ITC administered to rats or mice also showed both activities in vivo. As a result from elucidation of the platelet aggregation inhibition and the GST induction mechanisms of MS-ITC, the isothiocyanate moiety of MS-ITC plays an important role for antiplatelet and anticancer activities because of its high reactivity with sulfhydryl (RSH) groups in biomolecules (GSH, cysteine residue in a certain protein, etc.).

Animals↗

PubMed2000

Constitutive regulation of cardiac fatty acid metabolism through peroxisome proliferator-activated receptor alpha associated with age-dependent cardiac toxicity.

The peroxisome proliferator-activated receptor alpha (PPARalpha) is a member of the nuclear receptor superfamily and mediates the biological effects of peroxisome proliferators. To determine the physiological role of PPARalpha in cardiac fatty acid metabolism, we examined the regulation of expression of cardiac fatty acid-metabolizing proteins using PPARalpha-null mice. The capacity for constitutive myocardial beta-oxidation of the medium and long chain fatty acids, octanoic acid and palmitic acid, was markedly reduced in the PPARalpha-null mice as compared with the wild-type mice, indicating that mitochondrial fatty acid catabolism is impaired in the absence of PPARalpha. In contrast, constitutive beta-oxidation of the very long chain fatty acid, lignoceric acid, did not differ between the mice, suggesting that the constitutive expression of enzymes involved in peroxisomal beta-oxidation is independent of PPARalpha(.) Indeed, PPARalpha-null mice had normal levels of the peroxisomal beta-oxidation enzymes except the D-type bifunctional protein. At least seven mitochondrial fatty acid-metabolizing enzymes were expressed at much lower levels in the PPARalpha-null mice, whereas other fatty acid-metabolizing enzymes were present at similar or slightly lower levels in the PPARalpha-null, as compared with wild-type mice. Additionally, lower constitutive mRNA expression levels of fatty acid transporters were found in the PPARalpha-null mice, suggesting a role for PPARalpha in fatty acid transport and catabolism. Indeed, in fatty acid metabolism experiments in vivo, myocardial uptake of iodophenyl 9-methylpentadecanoic acid and its conversion to 3-methylnonanoic acid were reduced in the PPARalpha-null mice. Interestingly, a decreased ATP concentration after exposure to stress, abnormal cristae of the mitochondria, abnormal caveolae, and fibrosis were observed only in the myocardium of the PPARalpha-null mice. These cardiac abnormalities appeared to proceed in an age-dependent manner. Taken together, the results presented here indicate that PPARalpha controls constitutive fatty acid oxidation, thus establishing a role for the receptor in cardiac fatty acid homeostasis. Furthermore, altered expression of fatty acid-metabolizing proteins seems to lead to myocardial damage and fibrosis, as inflammation and abnormal cell growth control can cause these conditions.

Aging↗

PubMed2000

Identification of the messenger RNA for human cutaneous fatty acid-binding protein as a metastasis inducer.

Using our recently developed systematic differential display and complete comparison of gene expression approaches combined with other methods, we have identified a large number of mRNAs that are expressed differentially between benign and malignant human cells. One such mRNA that is common to prostate and breast carcinoma cell lines encodes the human cutaneous fatty acid-binding protein (C-FABP). Northern and slot blot analyses confirm that the expression levels of C-FABP mRNA in the malignant prostate and breast carcinoma cell lines are 4.9+/-0.9- to 16.9+/-2.1-fold higher than those expressed in the benign cell lines. A similar difference between the benign and malignant cell lines was also detected at the protein level. In situ hybridization experiments have detected overexpression of the mRNA for C-FABP in human prostate carcinoma tissues. Transfection of a C-FABP expression construct into the benign, nonmetastatic rat mammary epithelial cell line Rama 37 and inoculation of the C-FABP expression transfectants into syngeneic Wistar-Furth rats produce a significant number (P < 0.05) of animals with metastases (6 of 26 animals), whereas the control transfectants generated by the vector alone yield no such metastases. Measurements of mRNA and protein levels with Northern and Western blotting show that C-FABP is not expressed in the control transfectant cells produced by the vector alone but is highly expressed in the pool of C-FABP transfectants and-the sublines established from their metastases. Immunocytochemical staining with antibodies to C-FABP shows that C-FABP is not expressed in the primary tumors developed from the control transfectants that have failed to metastasize, but it is expressed in both the primary tumors developed from the C-FABP transfectants and their metastases. Reinoculation of the sublines established from metastases in syngeneic rats has produced a higher proportion (50%) of animals (7 of 14 animals) with metastases than that obtained in the first-round inoculations, indicating that the metastatic clones have been preferentially selected from the original pool of metastatic and nonmetastatic transfectant clones. These results have demonstrated that elevated expression of C-FABP can induce metastasis and that metastatic capability has been transferred in a genetically dominated manner in this Rama 37 model. Thus, we suggest that C-FABP is a metastasis-inducing gene, and under suitable conditions, it may induce metastasis of some human cancers.

Animals↗

PubMed2000

Methylation patterns of the E-cadherin 5' CpG island are unstable and reflect the dynamic, heterogeneous loss of E-cadherin expression during metastatic progression.

Metastatic progression of most common epithelial tumors involves a heterogeneous, transient loss of expression of the homotypic cell adhesion protein, E-cadherin, rather than the uniform loss of a functional protein resulting from coding region mutation. Indeed, whereas E-cadherin loss may promote invasion, reexpression may facilitate cell survival within metastatic deposits. The mechanisms underlying such plasticity are unclear. We now show that the heterogeneous loss of E-cadherin expression in primary human breast cancers reflects a heterogeneous pattern of promoter region methylation, which begins early prior to invasion. In cultured human tumor cells, such heterogeneous methylation is dynamic, varying from allele to allele and shifting in relation to the tumor microenvironment. Following invasion in vitro, which favors diminished E-cadherin expression, the density of promoter methylation markedly increased. When these cells were cultured as spheroids, which requires homotypic cell adhesion, promoter methylation decreased dramatically, and E-cadherin was reexpressed. These data show that the methylation associated with E-cadherin loss in human breast cancer is heterogeneous and unstable and suggest that such epigenetic plasticity may contribute to the dynamic, phenotypic heterogeneity that drives metastatic progression.

Alleles↗

PubMed2000

Myocardial ischemia due to coronary artery spasm during dobutamine stress echocardiography.

Dobutamine stress echocardiography (DSE) is a useful and safe provocation test for myocardial ischemia. Until now, the test has been focused only on the organic lesion in the coronary artery, and positive DSE has indicated the presence of significant fixed coronary artery stenosis. The aim of the present study is to examine whether myocardial ischemia due to coronary spasm is induced by dobutamine. We performed DSE on 51 patients with coronary spastic angina but without significant fixed coronary artery stenosis. All patients had anginal attacks at rest with ST elevation on the electrocardiogram (variant angina). Coronary spasm was induced by intracoronary injection of acetylcholine, and no fixed coronary artery stenosis was documented on angiograms in all patients. DSE was performed with intravenous dobutamine infusion with an incremental doses of 5, 10, 20, 30, and 40 microg/kg/min every 5 minutes. Of the 51 patients, 7 patients showed asynergy with ST elevation. All 7 patients (13.7%) had chest pain during asynergy, and both chest pain and electrocardiographic changes were preceded by asynergy. These findings indicate that dobutamine can provoke coronary spasm in some patients with coronary spastic angina. When DSE is performed to evaluate coronary artery disease, not only fixed coronary stenosis, but also coronary spasm should be considered as a genesis of asynergy.

Adrenergic beta-Agonists↗

PubMed2000

Frequent genetic heterogeneity in the clonal evolution of gynecological carcinosarcoma and its influence on phenotypic diversity.

Carcinosarcomas of the uterus, ovaries, and fallopian tubes are highly aggressive neoplasms with incompletely understood histogenesis. Although recent immunohistochemical, cell culture, and molecular genetic studies all favor these cancers to be monoclonal in origin, the extent of intratumoral genetic heterogeneity in these tumors with divergent histology has not been reported previously. For this study, we microdissected a total of 172 carcinomatous or sarcomatous foci from 17 gynecological carcinosarcomas and analyzed allelic status with 41 microsatellite markers on chromosomal arms 1p, 1q, 3p, 4q, 5q, 6q, 8p, 9p, 10q, 11p, 11q, 13q, 16q, 17p, 17q, 18q, and 22q. With the exception of a single case with microsatellite instability, we found shared allelic losses and retentions among multiple individually dissected foci of each case, strongly supportive of the concept of a monoclonal origin for these neoplasms. In eight of these cases, we also found heterogeneous patterns of allelic loss at limited numbers of chromosomal loci in either the carcinomatous or sarcomatous components of the neoplasms. These heterogeneous patterns of allelic losses were consistent with either genetic progression or genetic diversion occurring during the clonal evolution of these neoplasms. In two cases, we found the specific patterns of genetic progression to be consistent with sarcomatous components of the neoplasms arising from carcinomatous components. We conclude that most of the gynecological carcinosarcomas have a monoclonal origin, and that genetic progression and diversion parallel the development of divergent phenotypes in these tumors. Because phenotypically divergent areas of the tumors share numerous genetic alterations, this divergence most likely occurs relatively late in the evolution of these tumors.

Carcinosarcoma↗

PubMed2000

Cardiac sympathetic activity in the asymmetrically hypertrophied septum in patients with hypertension or hypertrophic cardiomyopathy.

BACKGROUND: In patients with essential hypertension (HT), proportional (symmetric) left ventricular hypertrophy (LVH) is common. In contrast, hypertrophic cardiomyopathy (HCM) is characterized by disproportional LVH and, in particular, asymmetric septal hypertrophy (ASH); however, some hypertensive patients also develop ASH. It has not been determined whether such cases represent a distinct type of hypertensive LVH or HCM combined with hypertension. HYPOTHESIS: The study was undertaken to evaluate sympathetic activity in the interventricular septum in patients with HT and ASH or in patients with HCM. METHODS: The patients were evaluated by I-123 meta-iodobenzylguanidine (MIBG) and thallium-201 (201Tl) single-photon emission computed tomography (SPECT), respectively. They were divided into three groups: patients with essential HT and symmetric septal hypertrophy (Group A), patients with HT and ASH (Group B), and patients with HCM and ASH (Group C). RESULTS: Compared with the lateral wall, early uptake of MIBG in the septum was significantly higher in Group B than in Group A, but not significantly different between Groups A and C. Compared with the lateral wall, early uptake of 201Tl in the septum did not differ among the three groups. No significant difference in the MIBG clearance in the lateral wall was seen among the three groups. By contrast, MIBG clearances in the septum and apex were significantly greater in Group C than in Groups A and B. There was an inverse correlation between systolic thickening and MIBG clearance in the septum. CONCLUSION: These findings suggest that sympathetic activity in the septum differs between patients with HT and ASH and patients with HCM.

3-Iodobenzylguanidine↗

PubMed2000

Sentinel lymph node biopsy using tin colloid RI and blue dye method.

Axillary dissection has been considered essential for breast cancer staging because nodal metastasis is the most powerful predictive factor for recurrence. On the other hand, morbidity, such as lymphedema and shoulder dysfunction, may occur. Sentinel node biopsy is a good way to avoid unnecessary axillary dissection. We used tin colloid as a carrier of Tc99m tracer together with the blue dye method. The detection rate of the sentinel node was 27 cases out of 29 (90%) for the blue dye method, 10 cases out of 19 (53%) for the RI method, and 27 out of 33 (82%) for the combined method. The detection rate of the RI method was improved after adding the subcutaneous injection over the tumor from 45% before adding the subcutaneous injection to 82% after adding it. The false negative rate was 11% for the blue dye method, 0% for the RI method, and 10% for the combined method. This yields a sensitivity of 89% for the blue dye method, 100% for the RI method, and 90% for the combined method. Specificity was 100% for all three methods. Accuracy was 96% for the blue dye method, 100% for the RI method, and 96% for the combined method. There were two false negative cases. The average number of sentinel lymph nodes was 2.12 for the dye method, 1.66 for the RI method, and 1.95 for the combined method. There were three of 49 cases with identified parasternal lymph nodes by RI imaging. Lymphatic mapping using tin colloid may be useful for detecting sentinel nodes.

Adult↗

PubMed2000

Lymph node metastasis from breast cancer diagnosed by F-18 FDG whole-body PET (case report).

We report a 48-year-old woman with lymph node (LN) metastases from breast cancer in whom diagnosis was difficult by conventional imaging methods but easy by F-18 fluorodeoxyglucose (FDG) PET. She was given a diagnosis of right breast cancer and then underwent modified radical mastectomy in December 1997. During routine CT and US studies in September 1998, a questionable LN measuring 1 cm in diameter was detected in the right supraclavicular region, but a definitive diagnosis of this LN was difficult by these tests. The patient underwent FDG PET test, which showed strong nodular activity (SUV= 7.1) in the right supraclavicular region, indicating a metastatic lesion. Moreover, an unexpected second metastatic LN lesion (SUV= 5.5) in the medial aspect of the right axillary was diagnosed by PET. The PET results were confirmed by pathological examination of the surgical specimens. FDG PET is a useful tool to detect small malignant lesions that are not easily diagnosed by conventional imaging techniques such as CT and US. It is expected that PET test will be feasible at many institutions.

Adenocarcinoma↗

PubMed2000

Outlining the body contours with scattered photons in lymphoscintigraphy for sentinel nodes.

Although lymphoscintigraphy is a useful method of detecting the sentinel nodes of malignancy, conventional lymphoscintigraphy images only the sentinel nodes without revealing their anatomical location. We, therefore, used scattered photons to attempt to outline the body contours of patients with either breast or esophageal cancer. Lymphoscintigraphy was performed 3 to 4 hours after the injection of 111 MBq of 99mTc tin colloid into the peritumoral region. Images were obtained with dual-energy windows of 130 to 150 keV for the primary photons and 70 to 110 keV for the scattered photons. The images constructed from the scattered photons clearly showed the contours of the body, and the fusion images constructed from the primary and scattered photons allowed for easy identification of the location of the sentinel nodes. The results of this study confirm that images obtained from scattered photons on lymphoscintigraphy are helpful in identifying the anatomical location of sentinel nodes.

Adult↗

PubMed2000

Mitral valve plasty using artificial chordae in a 1.5-year-old boy with congenital mitral stenosis and absent anterolateral chordae.

A 1.5-year-old boy with refractory heart failure due to congenital mitral stenosis exhibited fusion of the anterolateral leaflets associated with moderate mitral regurgitation due to absent anterolateral chordae. Fused leaflets were incised and the mitral valve opening improved. Mitral regurgitation increased due to the absence of chordae, so 2 pairs of artificial chordae of 5-0 expanded polytetrafluoroethylene suture were anchored to the hypoplastic anterolateral papillary muscle, then attached to the free margin of incised leaflets. Postoperative examination showed improved mitral opening without exacerbated mitral regurgitation.

Artificial Organs↗

PubMed2000

Early surgery for active infective endocarditis.

OBJECTIVE: The timing of surgery for active infective endocarditis remains controversial. In this report, we have reviewed 26 patients who underwent surgery for active infective native-valve endocarditis between April 1992 and December 1998. PATIENTS AND METHOD: There were 19 male and 7 female patients (mean age 45 years). The aortic valve was involved in 8 patients, the mitral valve in 6 patients, tricuspid valve in 2 patients, both aortic and mitral valves in 7 patients, both aortic and tricuspid valve in 2 patients, and both mitral and tricuspid valve in one patient. The most common microorganisms were streptococcal species. Preoperative high New York Heart Association functional class (III and IV) was presented in 20 patients (77%). Progressive heart failure and the echocardiographic findings of vegetation (larger than 1 cm) were the main operative indications. Emergency or urgent surgery was required in 18 patients (70%). All patients underwent valve replacement, involving 25 mechanical prosthesis and 8 bioprosthesis. RESULTS: The operative mortality was 7.8% (n = 2). In the two patients who died, the infection had extended to the deep cardiac tissue and to the cerebral artery. The mean follow-up of the 24 survivors was 33 months (range from 6 to 82 months). There was no late death and no recurrence of infective endocarditis. CONCLUSION: In case of active infective endocarditis, early surgical intervention is recommended in patients with rapidly progressive cardiac deterioration or vegetation seen on echocardiography.

Adolescent↗

PubMed2000

Bypass graft material and myocardial protective procedure in combined coronary artery bypass grafting and valve surgery.

OBJECTIVE: The aortic cross clamping time is prone to be longer when coronary artery bypass grafting (CABG) is combined with valve surgery. Therefore, the myocardium that is revascularized by in-situ internal thoracic artery graft is at risk to ischemia, and, myocardial protection is especially important in such operation. In this study, the effect of myocardial preservation of combined antegrade, retrograde and terminal warm blood cardioplegia during combined valve surgery and CABG using the internal thoracic artery as a bypass conduit was evaluated. METHODS: From November 1992 to August 1999, 15 patients received combined CABG and valve surgery. Among these 15 patients, 13 patients who did not need hemodialysis were divided into 2 groups, and a comparative study was done. In Group I (n = 5), only the saphenous vein graft was employed for combined CABG and valve surgery, and myocardial protection was done by combined antegrade and terminal warm blood cardioplegia. In Group II (n = 8), at least 1 in-situ internal thoracic artery graft was employed for CABG and valve surgery, and myocardial protection was done by combined antegrade, retrograde and terminal warm blood cardioplegia. RESULTS: Despite longer aortic cross clamping time in Group II, the peak creatine kinase-MB of Group II was significantly lower. In addition, the postoperative administration of dopamine tended to be less in Group II. CONCLUSION: Myocardial protection by combined antegrade, retrograde and terminal warm blood cardioplegia may be an effective adjunct to combined valve surgery and CABG employing the in-situ internal thoracic artery graft.

Aged↗

PubMed2000

Freehand cryopreserved mitral valve allograft with flexible ring in the pig.

OBJECTIVE: Cryopreserved valve allografts have proven satisfactory in aortic and pulmonary positions but not mitrally because of the difficulty in properly aligning the mitral valve allograft due to the complex subvalvular apparatus. To make the surgical procedure easier, we developed a freehand cryopreserved mitral valve allograft with a flexible ring. METHODS: Whole cryopreserved mitral valve allografts with the papillary muscle, chordae, and leaflets from donor pigs were implanted mitrally in recipient pigs under cardiopulmonary bypass divided into 2 experimental groups; control allografts without the ring (n = 6) (CA group) and allografts with a flexible ring (n = 7) (RA group). Postimplantation hemodynamics and valvular function were evaluated by measuring arterial pressure, left ventricular end diastolic pressure, and left atrial pressure and by evaluating 2-dimensional echocardiography. Allografts were evaluated pathohistologically after cryopreservation and surgery by light microscopy. RESULTS: Hemodynamics did not differ significantly between groups. Aortic cross-clamping and Cardiopulmonary bypass times were significantly shorter in the RA group than the CA group (p < 0.05). Pigs requiring optional procedures with sutured annuloplasty and valvuloplasty numbered more in the CA group than the RA group. Postoperative echocardiography showed satisfactory mitral valve opening in diastole and good leaflet coaptation in systole in both groups. Light microscopic examination of cryopreserved allografts after surgery showed almost normal structures. CONCLUSIONS: Acute hemodynamic function and morphology of freehand cryopreserved valve allografts implanted mitrally in pigs proved acceptable. Adaptation of the flexible ring to allografts might be useful for technical benefit to facilitate accurate positioning of mitral subvalvular apparatus at implantation.

Animals↗

PubMed2000

Polymorphisms in IgG Fc receptor IIB regulatory regions associated with autoimmune susceptibility.

Autoimmune diseases involve multiple genes. While functions of these genes are largely unknown, some may be related to an intrinsic hyperresponsiveness of B cells. B-cell responses are controlled by signaling thresholds through the B-cell antigen receptor (BCR) complex. The B1 isoform of type II IgG Fc receptors (FcgammaRIIB1) is exclusively expressed on B cells and serves as a negative regulator for inhibiting BCR-elicited activation. Thus, its allelic variants associated with functional deficits could be examined for possible associations with susceptibility to autoimmune diseases. We found that there are three types of polymorphisms in the reported FcgammaRIIB transcription regulatory regions in mouse strains. Compared to normal healthy mouse strains (group III), autoimmune disease-prone strains (group I) share three deletion sites: two in the promoter region and one in the third intron. Strains (group II) that per se are not autoimmune-prone, but have potentials to accelerate autoimmune diseases share two deletion sites in the third intron: one identical to that in group I and the other unique to group II. These polymorphisms correlated well with extents of down-regulation of FcgammaRIIB1 expression in germinal-center B cells upon stimulation with antigens and up-regulation of IgG antibody responses. Our data imply that these FcgammaRIIB polymorphisms are selected evolutionarily for natural defense against pathogens, and that such polymorphisms may, in turn, form the basis of one aspect of autoimmune susceptibility.

Animals↗

PubMed2000

Effect of sulfhydryl reagents on the regulatory system of the L-type Ca channel in frog ventricular myocytes.

The effects of sulfhydryl (SH) reagents on the L-type Ca current (ICa) were studied in frog ventricular myocytes using the whole-cell patch-clamp method. Methanethiosulfonate ethylammonium (MTSEA+) was found to enter the cell through the membrane and cause a remarkable increase in Ica from the intracellular side. Methanethiosulfonate ethyltrimethylammonium (MTSET+) and methanethiosulfonate ethylsulfonate (MTSES-) could not penetrate the membrane and were effective only when directly applied to the intracellular side. In addition, suppressive effects on ICa of these MTS reagents were indicated by the following observation. A progressive decay in the peak amplitude of ICa after establishing maximal ICa, stimulated by intracellular MTSET+, was prevented by adding extracellular dithiothreitol (DTT). The SH-oxidizing agents N-ethylmaleimide (NEM), chloramine-T (CL-T), 2,2'-dithiodipyridine (DTDP) and 2,2'-dithio-bis-5-nitropyridine (DTBNP) also exerted a stimulatory effect on Ica. The effect of SH reagents persisted even when cAMP production was inhibited with Rp-cAMP-S, or when G-protein was inhibited with 1 mM GDPbetaS, indicating that the effect is not due to cAMP production or G-protein stimulation. It is concluded that there are sites on the Ca channels that are subject to direct modification by SH reagents.

2,2'-Dipyridyl↗

PubMed2000

Expression of vascular endothelial growth factor in surgical specimens of hepatocellular carcinoma.

PURPOSE: Vascular endothelial growth factor (VEGF) has been reported to play an important role in angiogenesis in hepatocellular carcinoma (HCC). However, there is great variation in reports on the distribution of VEGF expression, especially in non-carcinoma liver cells. Furthermore, some reports have mentioned that endothelial cells were positive for VEGF antibody but have not evaluated its significance. In this study, we focused our attention to these problems and try to solve them. We also analyzed the factors influencing VEGF expression and evaluated the prognostic potential of VEGF protein in HCC. METHODS: We examined the VEGF expression in specimens surgically removed from 46 HCC patients and 3 patients with liver cancer metastatic from the colon, and in 4 specimens of liver tissue with benign disease, by immunohistochemical methods. RESULTS/CONCLUSIONS: VEGF was expressed in HCC cells and hepatocytes and on vascular endothelial cells. Our finding that about seven times more endothelial cells were positive for VEGF antibody in carcinoma areas than in non-carcinoma areas (P < 0.001) suggests that VEGF is a very important angiogenesis factor for HCC growth. VEGF expression in HCC cells and non-carcinoma liver cells and on endothelial cells did not closely correlate with the disease recurrence rate (P > 0.05), suggesting that VEGF expression may not be useful as an individual factor for estimating the prognosis of HCC. A statistical analysis of the relationships between VEGF expression and clinicopathological variables revealed the following: preoperative transcatheter arterial embolization enhanced VEGF expression in both HCC cells and non-carcinoma liver cells. The histological grade of HCC and the level of alanine aminotransferase was related to VEGF expression in non-carcinoma liver cells and on endothelial cells in HCC areas. Tumor size and the histological status of the accompanying chronic hepatitis also influenced the VEGF expression on endothelial cells. Our findings concerning not only HCC but also the surrounding liver and endothelial cells may provide useful information for further research on the role of VEGF expression in HCC patients.

Adult↗

PubMed2000

Development of an intragastric enteral model in the mouse: studies of alcohol-induced liver disease using knockout technology.

The establishment of a continuous intragastric enteral feeding protocol in the rat by Tsukamoto and French was a major development in research of alcohol-induced liver disease. Unlike other models which only produce fat, with this model, inflammation, necrosis, and fibrosis can now be studied. However, much of what has been learned to date involves inhibitors or nutritional manipulation which may not be specific. Knockout technology could avoid these potential problems. Therefore, we have adapted a rat long-term intragastric protocol to the mouse so that the knockout technology can be used to study the mechanism of alcohol-induced liver injury. Reactive free radicals are involved in the mechanisms of early alcohol-induced liver injury; however, the key source of these species remains unclear. Cytochrome P450 (CYP) 2E1 is induced predominantly in hepatocytes by ethanol and could be one source of reactive oxygen species leading to liver injury. On the other hand, NADPH oxidase or xanthine oxidase is also a potent source of free radicals. In studies using CYP2E1 and p47phox (NADPH oxidase-deficient) knockout mice with this enteral model, it was reported that oxidants from CYP2E1 play only a small role in the mechanisms of early alcohol-induced liver injury in the mouse. Further, free radicals from NADPH oxidase in Kupffer cells play an important role in early alcohol-induced liver injury. Thus, this new enteral mouse model using knockout technology will provide a powerful tool in alcohol research.

Animals↗