Brain-derived neurotrophic factor gene polymorphisms and Alzheimer?s disease

Several lines of evidence have made brain-derived neurotrophic factor (BDNF) an important candidate gene conferring risk for Alzheimer's disease (AD). Recently, three studies reported an association between two single-nucleotide polymorphisms (SNP)--i.e., C270T and G196A--in the BDNF gene and AD. This attempt to confirm these associations in a larger AD sample included examination of the linkage disequilibrium of these two SNPs. Comparison of 487 Japanese AD subjects with 471 cognitively normal elderly controls showed higher frequencies of the G allele (60.5 vs. 55.5%, p = 0.028) and of both the GG and GA genotypes (85.8 vs. 79.8%, p = 0.025) of the G196A polymorphism in AD subjects than in controls and higher frequency of the T allele of the C270T polymorphism in AD subjects who were negative for apolipotrotein E4 (2.0 vs. 4.4%, p = 0.035) or positive for AD family history (2.8 vs. 7.1%, p = 0.046). These findings suggest that BDNF gene polymorphisms play some role in the development of AD.

HMG-CoA reductase inhibitors prevent bone loss in patients with Type 2 diabetes mellitus

AIMS

It has been reported that 3-hydroxy-3-methylglutaryl co-enzyme A (HMG-CoA) reductase inhibitors increase bone mineral density (BMD) in vivo. We investigated the effect of HMG-CoA reductase inhibitors on BMD in patients with Type 2 diabetes mellitus.

PATIENTS AND METHODS

We selected 122 patients with Type 2 diabetes, who were not taking active vitamin D preparations. Their mean age was 67.3 +/- 9.2 years. They were divided into a control group (n=63) without HMG-CoA reductase inhibitor therapy and an HMG-CoA group (n=59) who were treated with these drugs. The BMD of the distal one-third of the radius was measured by dual-energy X-ray adsorptiometry at baseline and after 2 years.

RESULTS

There were no significant differences between the control and HMG-CoA groups at baseline with respect to age, gender, body mass index, duration of diabetes, haemoglobin A1c, fasting plasma glucose, adjusted calcium, serum phosphorus, alkaline phosphatase, albumin excretion rate and radial BMD. However, there was a significantly smaller annual decrease of the radial BMD in the HMG-CoA group. Multiple regression analysis with a forward elimination procedure revealed a positive correlation of the radial BMD Z-score with body mass index, while there was a negative correlation with alkaline phosphatase and albumin excretion rate. In addition, the annual rate of change of the radial BMD showed a positive correlation with HMG-CoA reductase inhibitor therapy.

CONCLUSIONS

These findings suggest that HMG-CoA reductase inhibitors may prevent bone loss in patients with Type 2 diabetes.

Hypothalamic neuronal histamine regulates sympathetic nerve activity and expression of uncoupling protein 1 mRNA in brown adipose tissue in rats

To clarify how hypothalamic neuronal histamine regulates peripheral energy expenditure, we investigated the effect of infusion of histamine into the third cerebral ventricle or discrete hypothalamic regions on sympathetic nerve activity and expression of uncoupling protein 1 (UCP1) mRNA in brown adipose tissue (BAT). Infusion of histamine (200 nmol) into the third cerebral ventricle of anesthetized rats significantly increased the electrophysiological activity of sympathetic nerves (P<0.01) and UCP1 mRNA expression in the BAT (P<0.05). Microinjection of histamine (10 nmol) into the paraventricular nucleus (PVN) and preoptic area (POA) produced similar significant increases in BAT sympathetic nerve activity (P<0.01 for each). By contrast, injection of histamine into the ventromedial hypothalamic nucleus or lateral hypothalamic area had no effect. We conclude that hypothalamic neuronal histamine may regulate energy expenditure in BAT through the activation of sympathetic nerves. The PVN and/or POA appear to be the principal hypothalamic sites that mediate the stimulatory effect of histamine on this efferent pathway.

Repeated adenoviral administration into the biliary tract can induce repeated expression of the original gene construct in rat livers without immunosuppressive strategies

BACKGROUND

Systemic adenoviral readministration appears to be limited by immunogenicity.

AIMS

We examined the feasibility of repeated adenovirus mediated gene transfer into the liver via the biliary tract.

METHODS

Recombinant adenoviruses carrying a reporter lacZ gene were infused retrogradely into the common bile duct of rats. Transduction efficiency of the lacZ gene was estimated histochemically and quantitatively.

RESULTS

Retrograde administration of recombinant adenoviruses into the common bile duct of rats resulted in efficient transgene expression in the liver, specifically in hepatocytes, but not in biliary epithelia. Transduction efficiency induced by intrabiliary adenoviral administration was not substantially different from that induced by intraportal adenoviral infusion. Transgene expression in the liver was however transient, and development of neutralising antibodies against adenovirus was observed in serum but not in bile. When adenoviruses were readministered into the common bile duct, successful re-expression of the transgene in the liver was achieved despite the existence of neutralising antibodies in serum. Interestingly, although proliferation of adenovirus specific T cells in response to adenoviral readministration was suppressed significantly by immunosuppressive FK506 treatment, levels of transgene expression in the liver achieved by intrabiliary adenoviral readministration were not significantly different between animals treated with and without FK506. Furthermore, third adenoviral administration into the common bile duct also induced successful transgene expression in the liver.

CONCLUSIONS

These results suggest that adenovirus mediated gene transfer into the liver may be repeatable without immunosuppressive strategies in clinical settings by means of endoscopic retrograde cholangiography.

An increased high-mobility group A2 expression level is associated with malignant phenotype in pancreatic exocrine tissue

The altered form of the high-mobility group A2 (HMGA2) gene is somehow related to the generation of human benign and malignant tumours of mesenchymal origin. However, only a few data on the expression of HMGA2 in malignant tumour originating from epithelial tissue are available. In this study, we examined the HMGA2 expression level in pancreatic carcinoma, and investigated whether alterations in the HMGA2 expression level are associated with a malignant phenotype in pancreatic tissue. High-mobility group A2 mRNA and protein expression was determined in eight surgically resected specimens of non-neoplastic tissue (six specimens of normal pancreatic tissue and two of chronic pancreatitis tissue) and 27 pancreatic carcinomas by highly sensitive reverse transcriptase–polymerase chain reaction (RT–PCR) techniques and immunohistochemical staining, respectively. Reverse transcriptase–polymerase chain reaction analysis revealed the expression of the HMGA2 gene in non-neoplastic pancreatic tissue, although its expression level was significantly lower than that in carcinoma. Immunohistochemical analysis indicated that the presence of the HMGA2 gene in non-neoplastic pancreatic tissue observed in RT–PCR reflects its abundant expression in islet cells, together with its focal expression in duct epithelial cells. Intense and multifocal or diffuse HMGA2 immunoreactivity was noted in all the pancreatic carcinoma examined. A strong correlation between HMGA2 overexpression and the diagnosis of carcinoma was statistically verified. Based on these findings, we propose that an increased expression level of the HMGA2 protein is closely associated with the malignant phenotype in the pancreatic exocrine system, and accordingly, HMGA2 could serve as a potential diagnostic molecular marker for distinguishing pancreatic malignant cells from non-neoplastic pancreatic exocrine cells.

Hypoglycaemia in patients with liver diseases administered levothyroxine

OBJECTIVE

Experience of a few hypoglycaemic patients with liver disease and receiving levothyroxine suggested to us that the prevalence of hypoglycaemia might be higher in such patients. The purpose of this study was to ascertain whether the prevalence of hypoglycaemia this was actually the case.

METHODS

This study was a retrospective, cross-sectional analysis of a medical computerized database and/or written reports from our university hospital. Patients with primary liver disease who were admitted to our hospital between April 1998 and August 2000 were divided into two groups; the first group received levothyroxine and the second group did not. The patients in the second group were selected from three different time periods within the period shown. The prevalence of hypoglycaemia (blood glucose level <70 mg/dL) was compared between the two groups.

RESULTS

The prevalence of hypoglycaemia was significantly higher in the group receiving levothyroxine compared with the group not receiving levothyroxine (four of eight patients (50.0%) vs. three of 59 (5.1%), P = 0.003, Fisher's exact test).

CONCLUSIONS

The results suggest that levothyroxine may be a risk factor for hypoglycaemia in patients with liver disease. While a larger study, perhaps with an alternative study design is needed to confirm this, and to investigate possible mechanisms of effect, it would be prudent to monitor the blood glucose level of such patients closely.

Predictive factors for malignancy in intraductal papillary-mucinous tumours of the pancreas

BACKGROUND

Preoperative assessment of the likelihood of malignancy in intraductal papillary-mucinous tumour (IPMT) of the pancreas is often difficult. Predictive factors for malignancy and invasive carcinoma in IPMT were analysed.

METHODS

Sixty-two patients with IPMT underwent surgical treatment, with histological confirmation of adenoma in 28, carcinoma in situ in 14 and invasive carcinoma in 20. Tumours were of the main duct type in 14 patients, branch duct type in 32, and combined type in 16. A multivariate analysis of 17 potential predictive factors, including preoperative clinical and imaging findings, was conducted.

RESULTS

Multivariate analysis identified two independent predictive factors for malignancy: mural nodules and main pancreatic duct diameter of 7 mm or more. Mural nodules in the main duct or combined type, and mural nodules and tumour diameter of 30 mm or more in the branch duct type were particularly indicative of malignancy. Mural nodules, jaundice and main duct or combined type were predictors of invasive carcinoma in the multivariate analysis.

CONCLUSION

The above factors should be considered in the diagnosis of IPMT to facilitate appropriate management.

Vascular endothelial growth factor and receptor interaction is a prerequisite for murine hepatic fibrogenesis

BACKGROUND

It has been shown that expression of the potent angiogenic factor, vascular endothelial growth factor (VEGF), and its receptors, flt-1 (VEGFR-1) and KDR/Flk-1 (VEGFR-2), increased during the development of liver fibrosis.

AIMS

To elucidate the in vivo role of interaction between VEGF and its receptors in liver fibrogenesis.

METHODS

A model of CCl(4) induced hepatic fibrosis was used to assess the role of VEGFR-1 and VEGFR-2 by means of specific neutralising monoclonal antibodies (R-1mAb and R-2mAb, respectively). R-1mAb and R-2mAb were administered after two weeks of treatment with CCl(4), and indices of fibrosis were assessed at eight weeks.

RESULTS

Hepatic VEGF mRNA expression significantly increased during the development of liver fibrosis. Both R-1mAb and R-2mAb treatments significantly attenuated the development of fibrosis associated with suppression of neovascularisation in the liver. Hepatic hydroxyproline and serum fibrosis markers were also suppressed. Furthermore, the number of alpha-smooth muscle actin positive cells and alpha1(I)-procollagen mRNA expression were significantly suppressed by R-1mAb and R-2mAb treatment. The inhibitory effect of R-2mAb was more potent than that of R-1mAb, and combination treatment with both mAbs almost completely attenuated fibrosis development. Our in vitro study showed that VEGF treatment significantly stimulated proliferation of both activated hepatic stellate cells (HSC) and sinusoidal endothelial cells (SEC). VEGF also significantly increased alpha1(I)-procollagen mRNA expression in activated HSC.

CONCLUSIONS

These results suggest that the interaction of VEGF and its receptor, which reflected the combined effects of both on HSC and SEC, was a prerequisite for liver fibrosis development.

pp60c-src activation in lung adenocarcinoma

Nine src family members are known including c-Src, c-Yes, c-Lck, c-Fyn, c-Hck, c-Lyn, c-Blk, c-Fgr and c-Yrk. They encode proteins with molecular weights of 55-62 kilodaltons (kDa), which are either cytoplasmic or membrane-associated protein tyrosine kinases. A close correlation exists between an elevated pp60c-src tyrosine kinase activity and cell transformation. However, the level of activation of pp60c-src in non-small cell lung cancers (NSCLC) remains obscure. The aim of this study was to examine the level of activity of pp60c-src in NSCLC. pp60c-src expression and in vitro protein tyrosine kinase activity in lung cancer tissue samples were measured by western blotting and in vitro kinase assays and compared with those in the surrounding non-tumour lung tissue from the same patient. pp60c-src phosphorylation was assessed by two-dimensional tryptic phosphopeptide mapping. The kinase activity of pp60c-src was significantly activated in NSCLC, especially in adenocarcinomas. In addition, the pp60c-src kinase activity increased with the size of the adenocarcinoma. Two-dimensional tryptic phosphopeptide mapping showed dephosphorylation of pp60c-src at Tyr 530 in adenocarcinomas. The proto-oncogene product, pp60c-src, was activated in NSCLC, especially in adenocarcinomas, in part through the dephosphorylation of Tyr 530. Our results suggest that activation of pp60c-src might play an important role in the progression of lung adenocarcinomas.

A case of gallbladder carcinoma diagnosed preoperatively by the detection of human telomerase reverse transcriptase mRNA in endoscopically obtained gallbladder bile

It is difficult to accurately diagnose the nature of polypoid lesions in the gallbladder. To increase diagnostic accuracy, we have developed an endoscopic technique for obtaining gallbladder bile, termed endoscopic transpapillary catheterization into the gallbladder (ETCG). We describe here a case of gallbladder carcinoma diagnosed preoperatively by the detection of human telomerase reverse transcriptase (hTERT) mRNA, a catalytic subunit of telomerase, in gallbladder bile obtained using the ETCG technique. A patient with a polypoid lesion 15 mm in diameter in the gallbladder was admitted to our hospital for further examinations. Gallbladder bile collected by the ETCG technique was evaluated cytologically and also analyzed for telomerase activity and hTERT mRNA. Although the results for cytology and telomerase activity were negative, that for hTERT mRNA was positive. Open surgery was carried out and it was confirmed that the lesion was an adenocarcinoma invading the subserosa. The molecular biological analysis of gallbladder bile collected using the ETCG technique was shown to be effective for diagnosing the nature of the polypoid lesion in the gallbladder.

Expression of p33(ING1) in hepatocellular carcinoma: relationships to tumour differentiation and cyclin E kinase activity

BACKGROUND

Inhibitor of growth-1 (ING1) is a new candidate for the tumour suppressor gene that encodes a 33k Da protein (p33(ING1)). While reduction of p33(ING1) is an important event in some human cancers, the expression of p33(ING1) in human hepatocellular carcinoma (HCC) remains to be examined. We evaluated p33(ING1) expression in various liver diseases including HCC.

METHODS

Expression of p33(ING1) was evaluated immunohistochemically not only in the normal liver (n = 5), but also in specimens of chronic hepatitis (n = 39) and HCC (n = 86). We also analysed the relationship between p33(ING1) expression and cyclin E kinase activity detected by autoradiography in 29 HCCs.

RESULTS

Expression of p33(ING1) was reduced in HCC, especially in moderately and poorly differentiated HCCs, and those at advanced stages. Furthermore, expression of p33(ING1) correlated inversely with cyclin E kinase activity.

CONCLUSIONS

These data suggest that reduction of p33(ING1) may contribute to the process of malignant transformation, progression and dedifferentiation of HCC via an increase of cyclin E kinase activity.

Combined use of percutaneous ethanol injection and radiofrequency ablation for the effective treatment of hepatocelluar carcinoma

Radiofrequency ablation (RFA) and percutaneous ethanol injection (PEI) therapy are currently used for the treatment of hepatocellular carcinoma (HCC). The purpose of this study was to evaluate the usefulness of combination therapy of PEI and RFA (PEI-RFA). Seventy-three patients with biopsy-proven HCC and liver cirrhosis underwent RFA after a bolus injection of ethanol into HCC. The volume of coagulated necrosis in the liver caused by PEI-RFA was estimated and compared with that by RFA alone. Coagulated necrosis areas in the liver of patients treated with PEI-RFA were significantly larger than those of patients treated with RFA alone. In PEI-RFA group, the volume of coagulated necrosis was significantly correlated with the amounts of ethanol injected into HCC. No major complications were observed during and after the PEI-RFA treatment. These results indicate that PEI-RFA is more effective than RFA alone and can make dramatic improvement of therapeutic effects in RFA therapy for HCC with fewer sessions of treatments. Therefore, PEI-RFA is considered to be a practical and promising option and may open up new avenues for the treatment of HCC.

Dose-dependent effect of an oral adsorbent, AST-120, in patients with early chronic renal failure

We evaluated the dose dependence of an oral adsorbent, AST-120, in 31 patients with early chronic renal failure (baseline serum creatinine: 1.2-3.0 mg/dl). Twenty-three patients were given AST-120 and eight patients were not. AST-120 was administered at three different maintenance doses, < 3.0 g, 3.0 g and 6.0 g/day, according to patients' ability to tolerate treatment. The treatment period was 12 months. The slope of the reciprocal of serum-creatinine concentration versus time was calculated to assess the progression of renal failure. This slope became significantly less steep after AST-120 treatment at 6.0 g/day, but did not change significantly at the other doses. These findings suggest that 6.0 g/day of AST-120 may delay the initiation of dialysis in patients with early chronic renal failure.

A comparison of alfacalcidol and menatetrenone for the treatment of bone loss in an ovariectomized rat model of osteoporosis

We conducted this study to evaluate the characteristic effects of alfacalcidol (ALF) and menatetrenone (VK) in preventing bone loss using an ovariectomized rat model of osteoporosis. Bilateral ovariectomy (OVX) or sham operation was performed on 10-month-old female Wistar rats. OVX caused a significant decrease in the bone mass and the mechanical strength of the lumbar vertebra as well as the femur 6 months after surgery. VK treatment (30 mg/kg, food intake) required a 6-month period to prevent the bone loss induced by estrogen deficiency, whereas ALF (0.1 or 0.2 mg/kg, p.o.) increased the bone mass and the mechanical strength of the lumbar vertebra as well as the femur in a 3-month treatment period, far above the level in the sham-operated rats. Neither ALF or VK caused hypercalcemia, despite administration for as long as 6 months. By doing a micro-CT analysis of the vertebral trabecular microstructure, it was revealed that ALF treatment increased the interconnections and the plate-like structures and that VK significantly increased the trabecular number. It was also indicated that the increase in spinal strength by ALF treatment was closely associated with improvement of the microstructure, but not VK. The results of histomorphometric analysis showed that ALF caused a significant suppression of bone resorption yet maintained formation in the endocortical perimeter, and also stimulated bone formation in the periosteal perimeter, thereby causing an increase in cortical area. No marked effect of VK on histomorphometric parameters was observed, whereas VK as well as ALF maintained the material strength at femoral midshaft of the normal level, suggesting that VK affected bone quality and thereby prevented the decrease in mechanical strength of femur caused by OVX. In conclusion, it was demonstrated that the two drugs, ALF and VK, differed markedly in their potency and mechanisms for improving bone strength. These results have important implications in understanding the characteristic actions of vitamin K and active vitamin D on bone metabolism.

Effects of lycopene and Sho-saiko-to on hepatocarcinogenesis in a rat model of spontaneous liver cancer

The Long-Evans Cinnamon (LEC) rat is a well-characterized model of spontaneous hepatocarcinogenesis. It has been shown that dietary administration of lycopene or the herbal medicine Sho-saiko-to (TJ-9) has anticarcinogenic activity, although the mechanism by which these products protect against carcinogenesis is not well known. We investigated the outcome of administration of lycopene and TJ-9 on the occurrence of hepatic neoplasia in LEC rats. A diet containing 0.005% lycopene (originally the product of tomato oleoresin containing 13% lycopene) and 1% TJ-9 (crude extracts of 7 herbs: bupleurum root, pinellia tuber, scutellaria root, jujube fruit, ginseng root, glycyrrhiza root, and ginger rhizome) was administered from 6 weeks of age until the rats were sacrificed at 76 weeks of age, at which time most of the nontreated animals were known to have hepatocellular carcinoma (HCC). Development of HCC in treated groups was analyzed histologically by comparison with untreated controls. Glutathione S-transferase placental form (GST-P) was analyzed by an immunohistochemical method. Concentration of copper, iron, and zinc, which appear to play a role in hepatocarcinogenesis in LEC rats, was analyzed. The percent areas of HCC in the liver specimens of control, lycopene, and TJ-9 groups were 17.9 +/- 17.1%, 27.2 +/- 20.8%, and 27.6 +/- 18.4%, respectively. These intergroup differences were not significant. The percent area, number of areas, and mean size of area staining positively for GST-P revealed no significant differences between the groups. The number of GST-P-positive areas within the HCC lesions was greater in the TJ-9 group than in the control or lycopene group (p = 0.024 and p = 0.012, respectively). The study also demonstrated a lower concentration of iron in livers of the lycopene group than the control group (p = 0.019). There were no differences in serum alpha-fetoprotein levels or the cumulative survival rates between the groups. In conclusion, long-term administration of lycopene or TJ-9 did not reduce the risk of hepatocarcinogenesis in LEC rats.

ED-71, a vitamin D analog, is a more potent inhibitor of bone resorption than alfacalcidol in an estrogen-deficient rat model of osteoporosis

Although active vitamin D is used in certain countries for the treatment of osteoporosis, the risk of causing hypercalcemia/hypercalciuria means that there is only a narrow therapeutic window, and this has precluded worldwide approval. The results of our previous animal studies have suggested that the therapeutic effect of active vitamin D on bone loss after estrogen deficiency can be dissociated at least partly from its effect of enhancing intestinal calcium absorption and suppressing parathyroid hormone (PTH) secretion. To test this, we compared the effects of ED-71, a hydroxypropoxy derivative of 1alpha,25-dihydroxyvitamin D3, with orally administered alfacalcidol, on bone mineral density (BMD) and the bone remodeling process as a function of their effects on calcium metabolism and PTH, in a rat ovariectomy (ovx) model of osteoporosis. ED-71 increased bone mass at the lumbar vertebra to a greater extent than alfacalcidol, while enhancing calcium absorption (indicated by urinary calcium excretion) and decreasing serum PTH levels to the same degree as alfacalcidol. ED-71 lowered the biochemical and histological parameters of bone resorption more potently than alfacalcidol, while maintaining bone formation markers. These results suggest that active vitamin D exerts an antiosteoporotic effect by inhibiting osteoclastic bone resorption while maintaining osteoblastic function, and that these anticatabolic/anabolic effects of active vitamin D take place independently of its effects on calcium absorption and PTH. The demonstration that ED-71 is more potent in these properties than alfacalcidol makes it an attractive candidate as an antiosteoporotic drug.