A case of methotrexate-related lymphoproliferative disease showing multiple liver lesions in a patient with rheumatoid arthritis.

A 66-year-old woman with rheumatoid arthritis (RA) who had been receiving methotrexate (MTX) for 2 years presented with tarry stools. Contrast-enhanced computed tomography (CT) of the abdomen revealed irregular wall thickening in the ileocecal region and multiple low-contrast masses in both lobes of the liver. Lower gastrointestinal endoscopy revealed a type 2 tumor in the ileocecal region with a semi-peripheral ulcer. Histological examination of liver and colon biopsies showed other iatrogenic immunodeficiency-associated lymphoproliferative disorder (Oi-LPD), diffuse large B-cell lymphoma type, with positivity for Epstein-Barr virus DNA. After withdrawal of MTX, the LPD lesions disappeared and the patient achieved remission. We considered this to be a sporadic case of Oi-LPD, diffuse large B-cell lymphoma type, in the liver and colon due to treatment with MTX. There has been no previous report of this condition with simultaneous hepatic and colonic lesions, and the present case is thought to be highly informative in relation to the pathogenesis.

Objective Response by mRECIST to Initial Lenvatinib Therapy Is an Independent Factor Contributing to Deep Response in Hepatocellular Carcinoma Treated with Lenvatinib-Transcatheter Arterial Chemoembolization Sequential Therapy.

Objective: There is limited information regarding the benefits of Lenvatinib-transcatheter arterial chemoembolization (LEN-TACE) sequential therapy for unresectable hepatocellular carcinoma (u-HCC). We compared the efficacy and safety of LEN-TACE sequential therapy to LEN monotherapy and investigated the factors contributing to the LEN-TACE sequential therapy deep response. Methods: We enrolled a multicenter cohort of 247 patients with u-HCC treated with LEN between 2018 and 2020. Propensity score matching identified 63 matching pairs of patients with well-balanced characteristics. We retrospectively compared the clinical outcomes, including overall survival (OS), progression-free survival (PFS), and incidence of adverse events (AEs), between the LEN-TACE and LEN monotherapy groups. Additionally, we evaluated the tumor response, change in albumin-bilirubin (ALBI) score, factors affecting PFS and OS, and independent predictors contributing to the LEN-TACE sequential therapy deep response. In this study, at eight weeks after resumption of LEN after initial TACE, "deep response" was defined as achieving complete response or partial response (PR) on modified Response Evaluation Criteria in Solid Tumors (mRECIST), and at least a 30% decrease in the sum of diameters of target lesions, taking the baseline sum diameters as the reference. Results: The OS and PFS in the LEN-TACE group were significantly higher than those in the LEN monotherapy group (p = 0.002 and p = 0.037, respectively). The incidence of AEs related to LEN was not significantly different between the two groups. In LEN-TACE sequential therapy, the objective response rate was 61.9%, and the disease control rate was 74.6%, according to the mRECIST criteria. No significant change in the ALBI score was observed during sequential LEN-TACE therapy. Multivariable analyses revealed that deep response was independently associated with the outcome of the initial response to LEN by mRECIST: PR (odds ratio: 5.176, 95% confidence interval: 1.528-17.537, p < 0.001). Conclusions: LEN-TACE sequential therapy may provide more clinical benefits than LEN monotherapy in u-HCC patients who responded to initial LEN treatment. Objective response according to mRECIST to initial LEN is an independent factor contributing to LEN-TACE sequential therapy deep response.

Influence of skeletal muscle volume loss during lenvatinib treatment on prognosis in unresectable hepatocellular carcinoma: a multicenter study in Tohoku, Japan.

Sarcopenia is associated with poor prognosis of patients with hepatocellular carcinoma (HCC). We investigated the association of skeletal muscle volume (SMV) and its change in HCC patients taking lenvatinib. In 130 HCC patients, psoas mass index (PMI) was calculated as the left-right sum of the major × minor axis of psoas muscle at the third lumbar vertebra, divided by height squared. Patients were classified into two groups (low and normal PMI) based on indices of < 6.0 cm2/m2 for man and < 3.4 cm2/m2 for women. Change in PMI per month during the lenvatinib administration period (ΔPMI/m) was calculated; and patients were classified into two groups (severe and mild atrophy) based on the ΔPMI/m rate, as ≥ 1% or < 1%, respectively. There was no significant difference in Overall survival (OS) between the low and normal PMI groups at the start of lenvatinib administration. OS was significantly lower in the severe atrophy group than in the mild atrophy group (median; 15.2 vs. 25.6 months, P = 0.005). Multivariate analysis revealed a significant association of severe atrophy with OS (hazard ratio 1.927, P = 0.031). Progressive loss of SMV is a strong predictor of poor prognosis in HCC patients taking lenvatinib.

Long-Term Efficacy and Safety of Rifaximin in Japanese Patients with Hepatic Encephalopathy: A Multicenter Retrospective Study.

Background: Rifaximin is commonly used for hepatic encephalopathy (HE). However, the effects of long-term treatment for Japanese people are limited. Therefore, this study aimed to investigate the effects and safety of long-term treatment with rifaximin on HE. Methods: A total of 215 patients with cirrhosis administered with rifaximin developed overt or covert HE, which was diagnosed by an attending physician for >12 months. Laboratory data were extracted at pretreatment and 3, 6, and 12 months after rifaximin administration. The long-term effect of rifaximin was evaluated, and the incidence of overt HE during 12 months and adverse events was extracted. Results: Ammonia levels were significantly improved after 3 months of rifaximin administration and were continued until 12 months. There were no serious adverse events after rifaximin administration. The number of overt HE incidents was 9, 14, and 27 patients within 3, 6, and 12 months, respectively. Liver enzymes, renal function, and electrolytes did not change after rifaximin administration. Prothrombin activity is a significant risk factor for the occurrence of overt HE. The serum albumin, prothrombin activity, and albumin−bilirubin (ALBI) scores were statistically improved after 3 and 6 months of rifaximin administration. Moreover, the same results were obtained in patients with Child−Pugh C. Conclusions: The long-term rifaximin treatment was effective and safe for patients with HE, including Child−Pugh C.

Intrahepatic distribution of nerve fibers and alterations due to fibrosis in diseased liver.

Autonomic nerve fibers in the liver are distributed along the portal tract, being involved in the regulation of blood flow, bile secretion and hepatic metabolism, thus contributing to systemic homeostasis. The present study investigated changes in hepatic nerve fibers in liver biopsy specimens from patients with normal liver, viral hepatitis and non-alcoholic steatohepatitis, in relation to clinical background. The areal ratio of nerve fibers to the total portal area was automatically calculated for each sample. The nerve fiber areal ratios (NFAR) for total nerve fibers and sympathetic nerve fibers were significantly lower in liver affected by chronic hepatitis, particularly viral hepatitis, and this was also the case for advanced liver fibrosis. However, the degree of inflammatory activity did not affect NFAR for either whole nerves or sympathetic nerves. Comparison of samples obtained before and after antiviral treatment for HCV demonstrated recovery of NFAR along with improvement of liver fibrosis.

A machine learning-based treatment prediction model using whole genome variants of hepatitis C virus.

In recent years, the development of diagnostics using artificial intelligence (AI) has been remarkable. AI algorithms can go beyond human reasoning and build diagnostic models from a number of complex combinations. Using next-generation sequencing technology, we identified hepatitis C virus (HCV) variants resistant to directing-acting antivirals (DAA) by whole genome sequencing of full-length HCV genomes, and applied these variants to various machine-learning algorithms to evaluate a preliminary predictive model. HCV genomic RNA was extracted from serum from 173 patients (109 with subsequent sustained virological response [SVR] and 64 without) before DAA treatment. HCV genomes from the 109 SVR and 64 non-SVR patients were randomly divided into a training data set (57 SVR and 29 non-SVR) and a validation-data set (52 SVR and 35 non-SVR). The training data set was subject to nine machine-learning algorithms selected to identify the optimized combination of functional variants in relation to SVR status following DAA therapy. Subsequently, the prediction model was tested by the validation-data set. The most accurate learning method was the support vector machine (SVM) algorithm (validation accuracy, 0.95; kappa statistic, 0.90; F-value, 0.94). The second-most accurate learning algorithm was Multi-layer perceptron. Unfortunately, Decision Tree, and Naive Bayes algorithms could not be fitted with our data set due to low accuracy (< 0.8). Conclusively, with an accuracy rate of 95.4% in the generalization performance evaluation, SVM was identified as the best algorithm. Analytical methods based on genomic analysis and the construction of a predictive model by machine-learning may be applicable to the selection of the optimal treatment for other viral infections and cancer.

[A case of fibrinogen storage disease with primary biliary cholangitis].

A 66-year-old woman was diagnosed as primary biliary cholangitis (PBC) and was previously hospitalized for ascites and jaundice. She came to our hospital for further examination of the liver by needle biopsy, which showed interface hepatitis that mainly comprised lymphocytes and inflammatory infiltrates in the bile duct in the portal area. On the other hand, numerous intracytoplasmic inclusions that were positive for fibrinogen immunostaining were seen in the lobular area. Finally, we histologically diagnosed as PBC with fibrinogen storage disease (FSD). FSD is rare disease that leads to liver damage caused by abnormal fibrinogen storage in the endoplasmic reticulum of hepatocytes, with only four cases reported in Japan until now.

Incidence of development of hepatocellular carcinoma in Japanese patients infected with hepatitis B virus is equivalent between genotype B and C in long term.

Hepatitis B virus (HBV) genotypes B (HBV/B) and C (HBV/C) are the most prevalent genotypes among Japanese patients with hepatitis. Reportedly, HBV/C infection has been associated with more severe disease progression, manifesting as developing cirrhosis and hepatocellular carcinoma (HCC), than HBV/B infection. However, no long-term studies have examined the development of HCC in HBV/B-infected patients in Japan. The aims of our study were to compare the incidence of HCC in HBV/B- or HBV/C-infected patients. A total of 241 patients were followed up among 295 hepatitis B surface antigen (HBsAg)-positive carriers. Genotypes of HBV were A in 1% (4/295), B in 61% (179/295), C in 37% (110/295) and D in 1% (2/295) patients, and 96% of HBV/B were infected with subgenotype Bj. The mean age at HCC diagnosis was significantly higher in HBV/B than in HBV/C (67.0 ± 10.0 vs 57.7 ± 8.0 years, P < 0.001). The value of FIB-4 index was significantly higher in HBV/B than in HBV/C (P < 0.01). The rate of HCC was higher in HBV/C than in HBV/B, and a significant difference was observed until the 20-year observation period (P = 0.048). However, thereafter, HCC associated with HBV/B increased, and no significant difference was observed between HBV/B and HBV/C. HCC development was consistently observed even in HBV/B infection, especially among elderly patients with advanced fibrosis compared with HBV/C. HBV/B-infected patients developed HCC later in life, and in the long term, we found no differences in incidence of HCC development rates between these two genotypes.

MiR-139-5p is associated with inflammatory regulation through c-FOS suppression, and contributes to the progression of primary biliary cholangitis.

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease characterized pathologically by destruction of intrahepatic bile ducts. PBC is largely classified into three subtypes based on clinical course: (i) gradually progressive, (ii) portal hypertension, and (iii) hepatic failure. Previous studies have indicated that serum levels of the pro-inflammatory cytokine TNF-α, is elevated in PBC patients with fibrosis. Although the severity of cholangitis might also be related to the PBC subtype, its etiology has been unclear. Several studies have shown that microRNAs (miRNAs) demonstrate specific expression patterns in various diseases. In the present study, we evaluated miRNA expression patterns among the PBC subtypes using comprehensive deep sequencing. We also carried out histologic examination by laser capture microdissection and investigated how the identified miRNAs were involved in PBC clinical progression using the miRNA transfection method. On average, ~11 million 32-mer short RNA reads per sample were obtained, and we found that the expression levels of 97 miRNAs differed significantly among the four groups. Heat mapping demonstrated that the miRNA profiles from hepatic failure and portal hypertension type were clustered differently from those of the gradually progressive type and controls. Furthermore, we focused on miR-139-5p, which has an adequate number of total short reads. Quantitative reverse transcription PCR showed that miR-139-5p was significantly downregulated in clinically advanced PBC. Also, examination of liver tissues demonstrated that the expression of lymphocyte-derived miR-139-5p was significantly higher in hepatocytes. In vitro, the level of TNF-α was significantly elevated in supernatant of cells with upregulation of miR-139-5p. Furthermore, c-FOS gene transcription was repressed. Thus, we have demonstrated a novel inflammation-regulatory mechanism involving TNF-α and c-FOS transcription through miR-139-5p in the NF-κB signaling pathway. We conclude that the specific miRNA miR-139-5p might be involved in the pathogenesis of PBC, especially during clinical progression.

Serum metabolome profiles characterized by patients with hepatocellular carcinoma associated with hepatitis B and C.

AIM: To clarify the characteristics of metabolite profiles in virus-related hepatocellular carcinoma (HCC) patients using serum metabolome analysis. METHODS: The serum levels of low-molecular-weight metabolites in 68 patients with HCC were quantified using capillary electrophoresis chromatography and mass spectrometry. Thirty and 38 of the patients suffered from hepatitis B virus-related HCC (HCC-B) and hepatitis C virus-related HCC (HCC-C), respectively. RESULTS: The main metabolites characteristic of HCC were those associated with glutathione metabolism, notably 13 γ-glutamyl peptides, which are by-products of glutathione induction. Two major profiles, i.e., concentration patterns, of metabolites were identified in HCC patients, and these were classified into two groups: an HCC-B group and an HCC-C group including some of the HCC-B cases. The receiver operating characteristic curve for the multiple logistic regression model discriminating HCC-B from HCC-C incorporating the concentrations of glutamic acid, methionine and γ-glutamyl-glycine-glycine showed a highly significant area under the curve value of 0.94 (95%CI: 0.89-1.0, P < 0.0001). CONCLUSION: The serum levels of γ-glutamyl peptides, as well as their concentration patterns, contribute to the development of potential biomarkers for virus-related HCC. The difference in metabolite profiles between HCC-B and HCC-C may reflect the respective metabolic reactions that underlie the different pathogeneses of these two types of HCC.

Epiregulin promotes the emergence and proliferation of adult liver progenitor cells.

We have previously reported that epiregulin is a growth factor that seems to act on liver progenitor cells (LPCs) during liver regeneration. However, the relationship between epiregulin and LPCs has remained unclear. The aim of the present study was to clarify the role of epiregulin during liver regeneration. The serum levels of epiregulin in patients with acute liver failure were examined. A liver injury model was developed using mice fed a diet containing 0.1% 3.5-diethoxycarbonyl-1.4-dihydrocollidine (DDC) to induce LPCs. We then evaluated the expression of epiregulin and LPCs in these mice. The proliferation of epithelial cell adhesion molecule + LPCs cultured with epiregulin was examined in vitro, and finally epiregulin was overexpressed in mouse liver. In patients with acute liver failure, serum epiregulin levels were elevated significantly. In DDC mice, LPCs emerged around the portal area. Epiregulin was also detected around the portal area during the course of DDC-induced liver injury and was partially coexpressed with Thy1. Serum epiregulin levels in DDC mice were also significantly elevated. Recombinant epiregulin augmented the proliferative capacity of the LPCs in a dose-dependent manner. In mice showing overexpression of epiregulin, the expression of PCNA on hepatocytes was increased significantly. Finally, LPCs emerged around the portal area after epiregulin gene delivery. We concluded that epiregulin promotes the proliferation of LPCs and DNA synthesis by hepatocytes and is upregulated in the serum of patients with liver injury. Furthermore, induction of epiregulin leads to the appearance of LPCs. Epiregulin would be a useful biomarker of liver regeneration.

Clinical manifestations of liver injury in patients with anorexia nervosa.

AIM: The number of Japanese patients with anorexia nervosa (AN) is increasing as society changes. Mild liver injury is a complication of AN in around 30% of cases. In some rare instances, patients present with severe liver injury similar to acute liver failure. However, there are numerous uncertainties over the clinical characteristics of this condition. The objective of the present study was to clarify the clinical characteristics of AN complicated by liver injury and to investigate the factors related to hepatic complications. METHODS: Thirty-seven patients hospitalized at our institution with a diagnosis of AN were enrolled as the study subjects. The study used clinical data obtained at the time of hospitalization. The enrolled patients underwent subgroup analysis and were categorized into three groups: (i) normal alanine aminotransferase (ALT), (ii) moderately elevated ALT, and (iii) highly elevated ALT. RESULTS: All of the study subjects were female with a median age of 24 years and presenting with marked weight loss (mean body mass index, 13 kg/m(2) ). Thirteen of the subjects had liver injury. We found that patients in the highly elevated ALT group had a significantly high blood urea nitrogen (BUN)/creatinine ratio, and a low blood sugar level. CONCLUSIONS: Our present findings indicate that AN patients with highly elevated ALT have a severe dehydration. This suggests that dysfunction of hepatic circulation accompanying severe dehydration due to malnutrition may be an important factor in the development of liver injury in AN patients.

Possible autoimmune hepatitis induced after chronic active Epstein-Barr virus infection.

Chronic active Epstein-Barr virus infection (CAEBV) can be manifested in a variety of systemic conditions, including interstitial pneumonia, malignant lymphoma, and coronary aneurysm. Sometimes it may be associated with hepatic failure, although the mechanism underlying CAEBV-related hepatotoxicity remains unclear. We encountered a case of autoimmune hepatitis (AIH) associated with CAEBV. A 61-year-old male was referred to our hospital because of abnormal liver enzyme levels after initial diagnosis of CAEBV had been made by laboratory tests and liver biopsy. On admission, positivity for anti-nuclear antibody was evident, and examination of the liver biopsy specimen showed findings compatible with AIH. Steroid administration was initiated, and the liver function parameters subsequently improved. Although phenotypic changes in liver biopsy specimens are rare in this condition, the present case could provide clues to the possible pathogenesis of AIH.

A case of adult type 1 Gaucher disease complicated by temporal intestinal hemorrhage.

A 21-year-old man with a history of sudden rectal hemorrhage was referred to our hospital. Examination disclosed thrombocytopenia and hepatosplenomegaly. A liver biopsy specimen demonstrated Gaucher cells in Glisson's capsule. Additional investigations revealed a low level of leukocyte ß-glucosidase activity and common mutations of the glucocerebrosidase gene, L444P/D409H. We diagnosed the patient with Gaucher disease type 1. He underwent enzyme replacement therapy. Thrombocytopenia and hepatosplenomegaly improved at a rate of approximately 50 and 20%, respectively, within 6 months. This case suggests that we must pay attention to adult Gaucher disease as a differential diagnosis for cryptogenic thrombocytopenia.

Dynamics of serum metabolites in patients with chronic hepatitis C receiving pegylated interferon plus ribavirin: a metabolomics analysis.

OBJECTIVES: Serum samples from patients with chronic hepatitis C were subjected to metabolomics analysis to clarify the pretreatment characteristics of their metabolites and also changes in specific metabolites resulting from antiviral therapy with pegylated interferon plus ribavirin (PegIFN/RBV). MATERIALS/METHODS: The serum levels of low-molecular-weight metabolites in the twenty patients before and 24weeks after completion of PegIFN/RBV therapy were analyzed using capillary electrophoresis and liquid chromatography-mass spectrometry. RESULTS: Ten patients showed a non-virological response (NVR) and 10 achieved a sustained virological response (SVR) with eradication of viremia. The pretreatment levels of tryptophan were significantly higher in the patients of SVR than in those of NVR (p=0.010). The area under the curve (AUC) value of tryptophan calculated from the receiver operating characteristic (ROC) curve for discriminating SVR from NVR was 0.84 (95% confidential interval, 0.66-1.02, p=0.010). The ROC curve of multiple logistic regression model incorporating the pretreatment levels of tryptophan and γ-glutamate-arginine showed that the AUC value was highly significant (AUC=0.92, 95% confidential interval, 0.79-1.05, p=0.002). Twenty four weeks after completion of treatment, the levels of γ-glutamyl dipeptides, glutamic acid, 5-oxoproline, glucosamine and methionine sulfoxide were decreased, whereas those of 5-methoxy-3-indoleacetate, glutamine, kynurenine and lysine were increased significantly (p<0.05) in both the NVR and SVR patients. CONCLUSIONS: The pretreatment serum levels of certain metabolites including tryptophan are associated with the response to PegIFN/RBV therapy. PegIFN/RBV therapy can ameliorate the oxidative stress responsible for glutathione metabolism.

Serum prolactin levels and prolactin mRNA expression in peripheral blood mononuclear cells in hepatitis C virus infection.

Prolactin is not only a pituitary hormone but an immunoregulatory hormone secreted from lymphocytes. Prolactin induction in relation to hepatitis C virus (HCV) infection has not been elucidated. The serum levels of prolactin were examined in 232 HCV-infected subjects positive for anti-HCV antibody and 65 healthy controls negative for it, who were recruited in the cohort study. The prolactin mRNAs were measured in peripheral blood mononuclear cells (PBMCs) of eleven healthy volunteers including five men and six women before and after stimulation by HCV in vitro. The serum level of prolactin and prolactin mRNA in PBMCs were measured by chemiluminescence immunoassay and real-time PCR, respectively. The serum levels of prolactin were significantly higher in the HCV-infected subjects (median: 7.5, IQR: 5.7-10.9 ng/ml) than in the controls (median: 5.6, IQR: 4.4-8.3 ng/ml) (P < 0.01). They were significantly higher in HCV-infected males (median: 8.0, IQR: 5.9-11.8 ng/ml) than in the controls (median: 4.8, IQR: 4.2-5.9 ng/ml) (P < 0.001), however, the difference was not significant between HCV-infected females (median: 7.3, IQR: 5.6-10.5 ng/ml) and the controls (median: 6.4, IQR: 5.3-9.8 ng/ml). The mRNA expression of prolactin was induced in PBMCs of all males, but it was induced in PBMCs of the two of six females examined in vitro. These results suggest that the serum level of prolactin is higher in HCV-infected males than in healthy males, and that HCV infection induces the mRNA expression of prolactin in PBMCs that is more apparent in male than in females.

Impaired mitochondrial ß-oxidation in patients with chronic hepatitis C: relation with viral load and insulin resistance.

BACKGROUND: Hepatic steatosis is often seen in patients with chronic hepatitis C (CH-C). It is still unclear whether these patients have an impaired mitochondrial ß-oxidation. In this study we assessed mitochondrial ß-oxidation in CH-C patients by investigating ketogenesis during fasting. METHODS: This study consisted of thirty patients with CH-C. Serum levels of insulin and hepatitis C virus (HCV) core protein were measured by chemiluminescence enzyme immunoassay. The subjects were then fasted, and venous blood samples were drawn 12 h and 15 h after the start of fasting. The levels of blood ketone bodies were measured by an enzymatic cycling method. The rate of change in total ketone body concentration was compared with that in eight healthy volunteers. RESULTS: The rate of change in total ketone body concentration between 12 h and 15 h after the start of fasting was significantly lower in CH-C patients than in healthy volunteers (129.9% (8.5-577.3%) vs. 321.6% (139.6-405.4%); P <0.01). The rate of change in total ketone body concentration in patients with a serum level of HCV core protein of 10000 fmol/L or higher was significantly lower than in patients with a level of less than 10000 fmol/L (54.8% (8.5-304.3%) vs. 153.6% (17.1-577.3%); P <0.05). The rate of change in total ketone body concentration in patients with a homeostasis model assessment of insulin resistance (HOMA-IR) of 2.5 or higher was significantly lower than in patients with a HOMA-IR of less than 2.5 (56.7% (8.5-186.7%) vs. 156.4% (33.3-577.3%); P <0.01). CONCLUSIONS: These results suggest that mitochondrial ß-oxidation is impaired, possibly due to HCV infection in patients with CH-C.

Bone marrow cell-based regenerative therapy for liver cirrhosis.

Bone marrow cells are capable of differentiation into liver cells. Therefore, transplantation of bone marrow cells has considerable potential as a future therapy for regeneration of damaged liver tissue. Autologous bone marrow infusion therapy has been applied to patients with liver cirrhosis, and improvement of liver function parameters has been demonstrated. In this review, we summarize clinical trials of regenerative therapy using bone marrow cells for advanced liver diseases including cirrhosis, as well as topics pertaining to basic in vitro or in vivo approaches in order to outline the essentials of this novel treatment modality.

Altered expression of diacylglycerol kinase isozymes in regenerating liver.

The liver possesses the capacity to restore its function and mass after injury. Liver regeneration is controlled through complicated mechanisms, in which the phosphoinositide (PI) cycle is shown to be activated in hepatocytes. Using a rat partial hepatectomy (PH) model, the authors investigated the expression of the diacylglycerol kinase (DGK) family, a key enzyme in the PI cycle, which metabolizes a lipid second-messenger diacylglycerol (DG). RT-PCR analysis shows that DGKζ and DGKα are the major isozymes in the liver. Results showed that in the process of regeneration, the DGKζ protein, which is detected in the nucleus of a small population of hepatocytes in normal liver, is significantly increased in almost all hepatocytes. However, the mRNA levels remain largely unchanged. Double labeling with bromodeoxyuridine (BrdU), an S phase marker, reveals that DGKζ is expressed independently of DNA synthesis or cell proliferation. However, DGKα protein localizes to the cytoplasm in normal and regenerating livers, but immunoblot analysis reveals that the expected (80 kDa) and the lower (70 kDa) bands are detected in normal liver, whereas at day 10 after PH, the expected band is solely recognized, showing a different processing pattern of DGKα in liver regeneration. These results suggest that DGKζ and DGKα are involved, respectively, in the nucleus and the cytoplasm of hepatocytes in regenerating liver.