Kyosuke Yamamoto

Effects of Momordica charantia powder on serum glucose levels and various lipid parameters in rats fed with cholesterol-free and cholesterol-enriched diets

The effects of dietary bitter melon (Momordica charantia) freeze-dried powder on serum glucose level and lipid parameters of the serum and liver were studied in rats fed diets supplemented with and without cholesterol. Rats were fed the diets for 14 days containing bitter melon freeze-dried powder at the level of 0.5, 1 and 3% without an added dietary cholesterol (experiment I) and those containing bitter melon at the level of 1% with or without 0.5% cholesterol and 0.15% bile acid (experiment II). No adverse effect of dietary bitter melon powder on growth parameters and relative liver weight were noted. Dietary bitter melon resulted in a consistent decrease in serum glucose levels in rats fed cholesterol-free diets, but not in those fed cholesterol-enriched diets, although no dose-response was noted. Addition of cholesterol to the diets as compared to those without added cholesterol caused hypercholesterolemia and fatty liver. Bitter melon had little effect on serum lipid parameters, except for high density lipoprotein (HDL)-cholesterol; HDL-cholesterol levels tended to decrease by dietary cholesterol, while they were consistently elevated by dietary bitter melon both in the presence and absence of dietary cholesterol, indicating an antiatherogenic activity of bitter melon. In addition, bitter melon exhibited a marked reduction in the hepatic total cholesterol and triglyceride levels both in the presence and absence of dietary cholesterol; the reduction of triglyceride levels in the absence of dietary cholesterol was in a dose-dependent manner. These results suggest that bitter melon can be used as a health food.

A 52-Week, Randomized, Open-Label, Parallel-Group Comparison of the Tolerability and Effects of Pitavastatin and Atorvastatin on High-Density Lipoprotein Cholesterol Levels and Glucose Metabolism in Japanese Patients with Elevated Levels of Low-Density Lipoprotein Cholesterol and Glucose Intolerance

BACKGROUND Statin therapy has been found to produce substantial reductions in low-density lipoprotein cholesterol (LDL-C) levels, resulting in a reduced risk for cardiovascular events. Recently, research interest has focused on modification of high-density lipoprotein cholesterol (HDL-C) levels for the potential prevention of cardiovascular events. The effects of pitavastatin and atorvastatin on HDL-C have not been directly compared. OBJECTIVES This study compared the effects of pitavastatin and atorvastatin on HDL-C and other lipids and glucose metabolism in Japanese patients with elevated LDL-C levels and glucose intolerance. The tolerability of the 2 treatments was also compared. METHODS This was a multicenter, open-label, parallel-group trial. Patients with LDL-C levels>or=140 mg/dL and glucose intolerance (defined according to Japanese criteria for borderline diabetes and World Health Organization criteria for impaired fasting glucose and impaired glucose tolerance) were randomly assigned to receive either pitavastatin 2 mg/d or atorvastatin 10 mg/d for 52 weeks. Levels of serum lipids and lipoproteins and measures of glucose metabolism (fasting insulin, fasting glucose, glycosylated hemoglobin, and homeostasis model assessment for insulin resistance) were obtained at baseline and at 8, 26, and 52 weeks of treatment. The effect of study drug on glucose metabolism was evaluated as a tolerability outcome. Tolerability was further assessed based on adverse events, either spontaneously reported or elicited by questioning; physical examination findings; and clinical laboratory test results. Study physicians rated the relationship of adverse events to study medication as unrelated, suspected, or probable. RESULTS Two hundred seven patients were enrolled in the study, and efficacy was evaluated in 173 patients (88 pitavastatin, 85 atorvastatin). Thirty-four patients were excluded for reasons including failure to start medication or lack of >or=6 months of follow-up. Women accounted for 62% (108/173) of the evaluable population, which had a mean age of 63.3 years and a mean weight of 63.0 kg; 89% (154/173) had diabetes mellitus. The percent change in HDL-C levels was significantly greater in the pitavastatin group compared with the atorvastatin group (8.2 vs 2.9, respectively; P=0.031), as was the percent change in apolipoprotein (Apo) A-I (5.1 vs 0.6; P=0.019). The percent change in LDL-C levels was significantly lower with atorvastatin compared with pitavastatin (-40.1 vs -33.0, respectively; P=0.002), as were the percent changes in non-HDL-C (-37.4 vs -31.1; P=0.004), Apo B (-35.1 vs -28.2; P<0.001), and Apo E (-28.1 vs -17.8; P<0.001). The significant results for these parameters were unchanged when all 189 subjects who received>or=1 dose of study medication were included in the analysis, using last-value-carried-forward methodology. There were no significant differences between treatments with respect to the measures of glucose metabolism. Both statins appeared to be well tolerated. Adverse events occurred in 9% (9/96) of the pitavastatin group and 14% (13/93) of the atorvastatin group (P=NS). Two patients in the pitavastatin group and none in the atorvastatin group had an alanine aminotransferase value>3 times the upper limit of normal (P=NS). CONCLUSIONS In these patients with elevated LDL-C levels and glucose intolerance, 52 weeks of treatment with pitavastatin 2 mg/d was associated with significantly greater increases in HDL-C and Apo A-I levels than atorvastatin 10 mg/d. Both treatments were well tolerated.

Effect of intravenous administration of apolipoprotein A-IV on patterns of feeding, drinking and ambulatory activity of rats

To characterize the anorectic effect of apolipoprotein A-IV (apo A-IV), we examined the effect of apo A-IV on the patterns of feeding, drinking and ambulation of rats fed ad libitum. A single dose of 200, 135 or 60 micrograms was infused intravenously through a chronically indwelling right atrial catheter just before the dark period. Apo A-IV suppressed food intake by decreasing meal size, but did not affect the interval between meals, the speed of eating, or the latency to eat the first meal after infusion. The anorectic effect of apo A-IV was dose-dependent and was effective for about 3 h after the infusion. The anorectic effect of apo A-IV is specific because inactivation of apo A-IV abolishes its anorectic effect. The anorectic effect of apo A-IV is not shared by apo A-I. Apo A-IV had no effect on drinking behavior or ambulatory activity. The results seem to indicate that apo A-IV specifically decreases the meal size, which supports our hypothesis that apo A-IV may act as a physiological signal for satiation after the ingestion of a lipid meal.

Hepatocyte growth factor induces collagenase (matrix metalloproteinase-1) via the transcription factor Ets-1 in human hepatic stellate cell line

BACKGROUND/AIMS Although hepatocyte growth factor recently has been shown to decrease hepatic fibrosis in animal models, the molecular mechanisms of this effects remain to be elucidated. We investigated regulation of collagenase expression by hepatocyte growth factor in hepatic stellate cells. METHODS A human hepatic stellate cell line, LI90, was treated with hepatocyte growth factor. Expression of collagenase, 72 kDa gelatinase, procollagen alpha 1(I), tissue inhibitor of matrix metalloproteinase-1, transforming growth factor-beta 1, or Ets-1, and carboxyterminal telopeptide of type I collagen was examined. Ets-1 binding activity was determined by gel mobility shift assay, collagenase promoter activity was evaluated by reporter gene assay. LI90 cells were also transfected with Ets-1 antisense oligonucleotides with or without hepatocyte growth factor. RESULTS Hepatocyte growth factor increased expression of collagenase mRNA and protein, and an increase in Ets-1 mRNA preceded the increase in collagenase mRNA. Collagenase activity and protein, and a degradation product of type I collagen were increased in the medium. Nuclear extracts from treated LI90 cells also showed increased Ets-1 binding activity. Hepatocyte growth factor and cotransfection of Ets-1 enhanced promoter activity of collagenase gene. Furthermore, treatment of LI90 cells with Ets-1 antisense oligonucleotides downregulated basal and hepatocyte growth factor-induced Ets-1 and collagenase mRNA expression. CONCLUSIONS Collectively, the results suggest that hepatocyte growth factor increases collagenase expression in hepatic stellate cells via the Ets-1 transcription factor-dependent manner.

Inverse association between coffee drinking and the risk of hepatocellular carcinoma: a case‐control study in Japan

Coffee use has consistently been associated with lower serum liver enzyme levels and a reduced risk of liver cirrhosis. A limited number of cohort and case‐control studies also suggest a decreased risk of hepatocellular carcinoma (HCC) among coffee drinkers, but mostly without consideration of hepatitis virus infection. In the present case‐control study, we recruited 209 incident HCC cases and three different controls (1308 community controls, 275 hospital controls, and 381 patients with chronic liver disease [CLD] without HCC), all of whom were aged 40–79 years and residents of Saga Prefecture, Japan. A questionnaire survey elicited information on coffee use during the last 1–2 years and 10 years before, and plasma hepatitis B surface antigen and antibodies to hepatitis C virus were tested for all but community controls. After adjustment for sex, age, heavy alcohol use, smoking status and hepatitis virus markers (except for community controls), coffee use during the last 1–2 years was associated with a decreased risk against any control group. For coffee use 10 years before, comparison between HCC cases and either community controls or CLD patients revealed a decreased risk; adjusted odds ratios for occasional use, 1–2 cups/day and ≥3 cups/day compared with no use were 0.33, 0.27 and 0.22 (P trend < 0.001), respectively, against community controls, and 0.86, 0.62 and 0.53 (P trend = 0.05), respectively, against CLD patients. These results suggest that coffee may protect against the development of HCC, yet further elaborate studies (hopefully, intervention studies) are warranted to corroborate these findings. (Cancer Sci 2007; 98: 214–218)

Effect of vitamin K2 on the recurrence of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is characterized by frequent recurrence, even after curative treatment. Vitamin K2, which has been reported to reduce HCC development, may be effective in preventing HCC recurrence. Patients who underwent curative ablation or resection of HCC were randomly assigned to receive placebo, 45 mg/day, or 90 mg/day vitamin K2 in double‐blind fashion. HCC recurrence was surveyed every 12 weeks with dynamic computed tomography/magnetic resonance imaging, with HCC‐specific tumor markers monitored every 4 weeks. The primary aim was to confirm the superiority of active drug to placebo concerning disease‐free survival (DFS), and the secondary aim was to evaluate dose‐response relationship. Disease occurrence and death from any cause were treated as events. Hazard ratios (HRs) for disease occurrence and death were calculated using a Cox proportional hazards model. Enrollment was commenced in March 2004. DFS was assessed in 548 patients, including 181 in the placebo group, 182 in the 45‐mg/day group, and 185 in the 90‐mg/day group. Disease occurrence or death was diagnosed in 58, 52, and 76 patients in the respective groups. The second interim analysis indicated that vitamin K2 did not prevent disease occurrence or death, with an HR of 1.150 (95% confidence interval: 0.843‐1.570, one‐sided; P = 0.811) between the placebo and combined active‐drug groups, and the study was discontinued in March 2007.

Menatetrenone, a Vitamin K2 Analogue, Inhibits Hepatocellular Carcinoma Cell Growth by Suppressing Cyclin D1 Expression through Inhibition of Nuclear Factor κB Activation

Purpose: Menatetrenone, a vitamin K2 analogue, plays an important role in the production of blood coagulation factors. Menatetrenone has also bee shown to have antineoplastic effects against several cancer cell lines including hepatocellular carcinoma (HCC) cells. However, the mechanisms by which vitamin K2 inhibits HCC cell growth have not bee fully clarified, and we therefore investigated the molecular basis of vitamin K2–induced growth inhibition of HCC cells. Experimental Design: HCC cells were treated with vitamin K2 and the expression of several growth-related genes including cyclin-dependent kinase inhibitors and cyclin D1 was examined at the mRNA and protein levels. A reporter gene assay of the cyclin D1 promoter was done under vitamin K2 treatment. The regulation of nuclear factor κB (NF-κB) activation was investigated by a NF-κB reporter gene assay, an electrophoretic mobility shift assay, a Western blot for phosphorylated IκB, and an in vitro kinase assay for IκB kinase (IKK). We also examined the effect of vitamin K2 on the growth of HCC cells transfected with p65 or cyclin D1. Results: Vitamin K2 inhibited cyclin D1 mRNA and protein expression in a dose-dependent manner in the HCC cells. Vitamin K2 also suppressed the NF-κB binding site-dependent cyclin D1 promoter activity and suppressed the basal, 12-O-tetradecanoylphorbol-13-acetate (TPA)–, TNF-α–, and interleukin (IL)-1–induced activation of NF-κB binding and transactivation. Concomitant with the suppression of NF-κB activation, vitamin K2 also inhibited the phosphorylation and degradation of IκBα and suppressed IKK kinase activity. Moreover, HCC cells overexpressing cyclin D1 and p65 became resistant to vitamin K2 treatment. Conclusion: Vitamin K2 inhibits the growth of HCC cells via suppression of cyclin D1 expression through the IKK/IκB/NF-κB pathway and might therefore be useful for treatment of HCC.

Gln27Glu β2-adrenergic receptor variant is associated with hypertriglyceridemia and the development of fatty liver

BACKGROUND Nonalcoholic steatohepatitis (NASH) is associated with the metabolism of lipid, glucose and energy. Beta-adrenergic receptors play an important role in the regulation of energy expenditure, in part, by stimulating lipid mobilization through lipolysis. METHODS To assess whether it is common for the beta2-adrenergic receptor (B2AR) gene polymorphisms in codons 16 and 27 to play a role in the development of fatty liver, we investigated 251 unrelated healthy Japanese males who were drug-free and showed no signs of heavy drinking. RESULTS The allelic frequency of B2AR gene mutation in codons 16 and 27 did not differ between obese subjects (BMI>25.0 kg/m(2), n=151) and non-obese subjects (BMI</=25.0 kg/m(2), n=100). The Gly16 homozygotes had a lower high-density lipoprotein cholesterol (HDL-C) level than the Arg16 homozygotes (1.50+/-0.4 vs. 1.32+/-0.3 mmol/l, p=0.014). However, no significant association with fatty liver was observed in the Gly16 allele frequency. The Gln27Glu27 heterozygotes showed higher concentrations of serum triglycerides (TG) than the Gln27Gln27 homozygotes (1.62+/-0.93 vs. 2.21+/-1.67 mmol/l, p=0.013). This correlation was also observed in all subjects regardless of weight classification. Univariate analysis indicated that subjects with the heterozygous Gln27Glu mutant alleles had a significantly higher prevalence of fatty liver vs. those without the mutation (Glu27 allele frequency, 0.07 vs. 0.12, p=0.047; odds ratio, 1.92; 95% confidence interval, 1.01-3.68). However, multivariate logistic regression models showed the prevalence of fatty liver to be significantly related to the homeostasis model assessment (HOMA) index, BMI, triglyceride and HDL-cholesterol. CONCLUSIONS These results suggest that the amino-terminal polymorphisms of the beta2-adrenergic receptor gene in codon 27 were associated with hypertryglyceridemia and independent of obesity, and thereby could be involved in the molecular pathogenesis of fatty liver.

Influence of alcohol consumption and gene polymorphisms of ADH2 and ALDH2 on hepatocellular carcinoma in a Japanese population.

Although alcohol intake as well as hepatitis viruses has been associated with hepatocellular carcinoma (HCC), gene–alcohol interactions on HCC risk remain to be elucidated. We conducted a case‐control study to examine whether polymorphisms of alcohol dehydrogenase 2 (ADH2) and aldehyde dehydrogenase 2 (ALDH2) modified the HCC risk depending on the amount of alcohol intake. ADH2 and ALDH2 genotyping was performed by a duplex polymerase chain reaction with confronting two‐pair primers in 209 newly diagnosed HCC cases and 2 different controls [275 hospital controls and 381 patients with chronic liver disease (CLD)]. Multiple logistic regression analyses revealed that heavy drinkers consuming ≥3 “go”s/day of sake (69 g of ethanol/day) showed an increased risk of HCC based on comparison of HCC cases with hospital controls [adjusted odds ratio (OR) = 13.5; 95% confidence interval (CI) 3.3–54.3] or CLD patients (adjusted OR = 7.0; 95% CI 2.5–19.2), whereas the overall risk was not elevated among light to moderate drinkers consuming <3 “go”s/day. Interestingly, light to moderate drinking was associated with an increased risk among those with ALDH2*1/*2 (adjusted OR = 4.5 or 2.0), but not among those with ALDH2*1/*1 (adjusted OR = 0.8 or 1.0; p interaction = 0.03 or 0.13). However, this gene–alcohol interaction was not observed for heavy drinking. Among light to moderate drinkers, people with the combination of ALDH2*1/*2 and ADH2*2/*2 revealed the highest risk of HCC. These findings indicate that the ALDH2 polymorphism may modify HCC risk among light to moderate drinkers.

Interaction between cytochrome P450 1A2 genetic polymorphism and cigarette smoking on the risk of hepatocellular carcinoma in a Japanese population

Limited epidemiological evidence suggests that genetic polymorphisms of drug-metabolizing enzymes such as cytochrome P450 (CYP), glutathione S-transferase (GST) and N-acetyltransferase (NAT) may be involved in tobacco-related hepatocarcinogenesis. We conducted a case-control study, including 209 incident cases with hepatocellular carcinoma (HCC) and two different control groups [275 hospital controls and 381 patients with chronic liver disease (CLD) without HCC], to investigate whether CYP1A1, CYP1A2, CYP2A6, CYP2E1, GSTM1 and NAT2 polymorphisms are related to the risk of HCC with any interaction with cigarette smoking. Overall, no significant associations with HCC were observed for any genotypes against either control group. However, we found a significant interaction (P = 0.0045) between CYP1A2 -3860G>A polymorphism and current smoking on HCC risk when we compared HCC cases with CLD patients; adjusted odds ratios [ORs; and 95% confidence intervals (CIs)] for G/A and A/A genotypes relative to G/G genotype were 0.28 (0.12-0.66) and 0.18 (0.04-0.94), respectively, among current smokers (P trend = 0.002), as compared with 1.28 (0.80-2.06) and 0.76 (0.34-1.71), respectively, among never/former smokers (P trend = 0.96). Similarly, in CYP1A2 G/G genotype, significant risk increase was observed for current smoking (OR = 4.08, 95% CI = 2.02-8.25) or more recent cigarette use (e.g. pack-years during last 5 years, P trend = 0.0003) but not in G/A and A/A genotypes combined (OR for current smoking = 1.39, 95% CI = 0.63-3.03; P trend for pack-years during last 5 years = 0.40). These results suggest that the CYP1A2 -3860G>A polymorphism modifies the smoking-related HCC risk among CLD patients.