Pancreatic B-cell function is altered by oxidative stress induced by acute hyperglycaemia.

AIMS: Type 2 diabetes is preceded by a symptom-free period of impaired glucose tolerance (IGT). Pancreatic B-cell function decreases as glucose intolerance develops. In many patients with IGT, fasting blood glucose is within normal limits and hyperglycaemia occurs only postprandially. We examined whether pancreatic B-cell function changes during acute hyperglycaemia induced by oral glucose loading. METHODS: We calculated the insulinogenic index (I.I.) as an indicator of pancreatic B-cell function and measured serum levels of thioredoxin, a marker of cellular redox state, and 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress, during a 75-g oral glucose tolerance test (OGTT) in 45 subjects [24 patients with normal glucose tolerance (NGT), 14 with IGT and seven with Type 2 diabetes]. RESULTS: Thioredoxin levels decreased after glucose loading [66.1 +/- 23.7, *59.3 +/- 22.4, *49.3 +/- 21.2 and *37.7 +/- 18.0 ng/ml, fasting (0 min) and at 30, 60 and 120 min, respectively; *P < 0.001 vs. fasting]. In contrast, concentrations of 8-OHdG peaked at 30 min and then gradually decreased (0.402 +/- 0.123, *0.440 +/- 0.120, 0.362 +/- 0.119 and 0.355 +/- 0.131 ng/ml, *P < 0.05 vs. fasting, P < 0.01 vs. 30 min). The insulinogenic index correlated with the change in thioredoxin levels (r = 0.34, P < 0.05). However, there was no relationship with the change in 8-OHdG levels from 0 to 30 min. CONCLUSIONS: Hyperglycaemia in response to oral glucose impairs pancreatic B-cell function with decreasing thioredoxin levels. The augmented oxidative stress induced by hyperglycaemia may affect the cellular redox state. These findings strongly suggest that repeated postprandial hyperglycaemia may play an important role in the development and progression of diabetes mellitus.     

Usefulness of hydrophilic vs lipophilic statins after acute myocardial infarction: subanalysis of MUSASHI-AMI.

BACKGROUND: Statins are widely used to reduce blood levels of low-density lipoprotein-cholesterol (LDL-C). Each statin has unique pharmacokinetic properties; lipophilicity is one such property and relates to tissue selectivity. METHODS AND RESULTS: The Multicenter Study for Aggressive Lipid-lowering Strategy by HMG-CoA Reductase Inhibitors in Patients with Acute Myocardial Infarction (MUSASHI-AMI) trial evaluated the effect of discretional statin treatment initiated within 96 h after onset of acute myocardial infarction (AMI) in Japanese patients. To clarify whether statin lipophilicity affects prognosis, a post hoc analysis of the MUSASHI-AMI database was performed. Patients who were assigned to receive statin were separated into 2 groups according to the lipophilicity of the statins they were administered: lipophilic statins (atorvastatin, fluvastatin, pitavastatin and simvastatin; LS group; n=131) or hydrophilic statins (pravastatin; HS group; n=110). There was no difference in baseline LDL-C concentrations between the 2 groups. Although LDL-C was decreased more potently in the LS than HS groups (-34% vs -19%; p=0.0069), acute coronary syndrome events tended to occur less frequently (3.6% vs 9.9%; p=0.0530) and the incidence of new Q-wave appearance in electrocardiogram was significantly lower (75% vs 89%; p=0.0056) in the HS than LS groups. CONCLUSIONS: In normocholesterolemic Japanese patients after AMI, hydrophilic pravastatin could be superior to lipophilic statins at preventing new Q-wave appearance and reducing cardiovascular events.     

Dietary whey protein hydrolysate suppresses development of atopic dermatitis-like skin lesions induced by mite antigen in NC/Nga mice.

BACKGROUND: Oral administration of enzymatic hydrolysate of cow's milk whey protein (WPH) has been reported to produce an anti-inflammatory effect. Since inflammation plays a role in dermatitis of allergic disease, we examined the influence of WPH on the development of atopic dermatitis (AD)-like skin lesions, induced in NC/Nga mice by the mite antigen Dermatophagoides pteronyssinus (Dp). METHODS: AD-like skin lesions were induced on the pinnae and backs of NC/Nga mice by daily application of Dp for 4 weeks. Mice were fed cow's milk casein (control), WPH or casein protein hydrolysate (CPH) diets for 2 weeks prior to Dp application. Clinical skin conditions were evaluated periodically by a clinical severity score, total serum IgE and soluble E-selectin levels were measured by enzyme linked immunosorbent assay (ELISA). RESULTS: WPH-fed mice showed significantly less AD-like skin lesions than those fed casein diets at 2 and 4 weeks after Dp application. In contrast, CPH-fed mice had manifestations in a similar manner as casein-fed mice did, and did not show an inhibitory effect. Serum soluble E-selectin levels, known as a marker of disease activity in AD patients, were significantly lower in the WPH diet group. CONCLUSIONS: Our results suggest that in addition to its hypoallergenicity an anti-inflammatory function, dietary WPH might be useful for reducing the severity of AD-like skin lesions.     

Thyroxine to triiodothyronine hyperconversion thyrotoxicosis in patients with large metastases of follicular thyroid carcinoma.

OBJECTIVE: We experienced two cases of follicular thyroid carcinoma with distant metastases, which showed high levels of free triiodothyronine (T(3)) while free thyroxine (T(4)) levels remained in the low or normal range. In this report, we described the detail of these cases and examined the cause of T(3) thyrotoxicosis. DESIGN: In one of the cases, quantitative measurement of types I and II iodothyronine deiodinase mRNAs was performed using a surgically dissected tissue from the primary tumor and a distant metastasis. MAIN OUTCOME: In the both tissues, types I and II iodothyronine deiodinase mRNAs were expressed in the same level as in the normal thyroid tissues. CONCLUSION: These results suggest that T(3) thyrotoxicosis in our patients was caused by hyperconversion of administered levothyroxine to T(3). In the follow-up of patients with distant metastases of follicular carcinoma, not only free T(4), but also free T(3) should be tested to avoid the excessive administration of levothyroxine.     

A case of Crohn's disease with recurrent massive life-threatening hemorrhage from terminal ileum.

A case of Crohn's disease that underwent bowel resection two times at 3-year intervals due to life-threatening hemorrhage from ileum is presented. The bleeding sites were located in the ulcer lesions of ileum, in the oral side near to the ileum-colon transition. The first bleeding point was at the longitudinal ulcer of the terminal ileum and the secondary bleeding site was at the profound ulcer of ileum appearing in the oral side near to the ileo-colic anastomosis. This is the first case of Crohn's disease with recurrent life-threatening massive hemorrhage in the terminal region of ileum, for which operative bowel resections were necessary. This case suggests that we should search for the bleeding site in ileal lesions developed in the circumference of and especially the oral side near to the anastomosis due to prior resection, when intestinal massive bleeding occurs again after bowel resection, and that the careful follow-up and strict treatment with diet therapy and/or anti-inflammatory drugs are necessary for the protection of recurrence in patients with Crohn's disease.     

Successful Low-Dose Chemotherapy Using Vinblastine and Methotrexate for the Treatment of an Ileoanal Pouch Mesenteric Desmoid Tumor: Report of a Case

The purpose of this report was to describe the first known case of ileoanal pouch salvage by a low-dose regimen of vinblastine and methotrexate chemotherapy for the treatment of desmoid tumor arising from the mesentery of the ileoanal pouch in a patient who had undergone ileal pouch-anal anastomosis for familial adenomatous polyposis. Mesenteric desmoid tumor involving the ileoanal pouch in a 28-year-old female was treated with vinblastine and methotrexate biweekly for 12 months and monthly for 12 months in an outpatient unit. The desmoid tumor response to the treatment was assessed at routine intervals by physical examination and magnetic resonance imaging. Desmoid tumor was successfully treated with a low-dose regimen of vinblastine and methotrexate chemotherapy without significant side effects, and function of the ileoanal pouch was fully preserved. Magnetic resonance imaging showed a decrease in desmoid tumor size and cellularity, and changes consistent with fibrosis. This is a unique case highlighting the possibility of ileoanal pouch salvage by low-dose combination chemotherapy using vinblastine and methotrexate in a familial adenomatous polyposis patient with mesenteric desmoid tumor.     

Subchronic exposure to arsenic through drinking water alters expression of cancer-related genes in rat liver

Although arsenic exposure causes liver disease and/or hepatoma, little is known about molecular mechanisms of arsenic-induced liver toxicity or carcinogenesis. We investigated the effects of arsenic on expression of cancer-related genes in a rat liver following subchronic exposure to sodium arsenate (1, 10, 100 ppm in drinking water), by using real-time quantitative RT-PCR and immunohistochemical analyses. Arsenic accumulated in the rat liver dose-dependently and caused hepatic histopathological changes, such as disruption of hepatic cords, sinusoidal dilation, and fatty infiltration. A 1-month exposure to arsenic significantly increased hepatic mRNA levels of cyclin D1 (10 ppm), ILK (1 ppm), and p27(Kip1) (10 ppm), whereas it reduced mRNA levels of PTEN (1 ppm) and beta-catenin (100 ppm). In contrast, a 4-month arsenic exposure showed increased mRNA expression of cyclin D1 (100 ppm), ILK (1 ppm), and p27(Kip1) (1 and 10 ppm), and decreased expression of both PTEN and beta-catenin at all 3 doses. An immunohistochemical study revealed that each protein expression accords closely with each gene expression of mRNA level. In conclusion, subchronic exposure to inorganic arsenate caused pathological changes and altered expression of cyclin D1, p27(Kip1), ILK, PTEN, and beta-catenin in the liver. This implies that arsenic liver toxicity involves disturbances of some cancer-related molecules.     

Reactive oxygen species-producing site in hydrogen peroxide-induced apoptosis of human peripheral T cells: involvement of lysosomal membrane destabilization

In our previous study, we examined the effect of exogenous hydrogen peroxide, which causes a potent oxidative stress and has been demonstrated to be a potent apoptosis-inducer in many kinds of cells. We found that the addition of 1 or 10 mM hydrogen peroxide induced reactive oxygen species (ROS) formation, oxidative DNA damage, dysfunction of the mitochondrial membrane potential, and early apoptotic changes in the human osteosarcoma cell line HS-Os-1. We therefore concluded that intracellular ROS formation was involved in the hydrogen peroxide-induced apoptosis of HS-Os-1 cells. In contrast to the osteosarcoma cell line HS-Os-1, human peripheral T cells are considered to be easily susceptible to oxidative stress, because these cells lack peroxidase activity. Therefore, in this study, we investigated the site of ROS formation by utilizing MitoCapture, H2DCFDA (succinimidyl ester of dichloro-dihydrofluorescein diacetate), DAPI (4',6-diamidino-2-phenylindole), and LysoSensor. Our results showed that ROS formation was apparently diffusely distributed in T cells oxidatively stressed with 0.1 mM hydrogen peroxide. Moreover, lysosomal swelling and deformity, possibly revealing lysosomal membrane destabilization, were observed in these cells. Based on the above results, there exists an apoptotic cascade involving early lysosomal membrane destabilization in the hydrogen peroxide-induced apoptosis of human peripheral T cells. Therefore, the possible involvement of lysosomal protease leakage caused by hydroxyl radical formation in lysosomes (possibly resulting in mitochondrial membrane dysfunction) is considered to play an important role in hydrogen peroxide-induced T cell apoptosis.