Immunomodulation by juglone alleviates acute graft-versus-host disease without compromising the graft-versus-leukaemia activity in mice

BACKGROUND AND PURPOSE

Acute graft-versus-host disease (GVHD) remains a major barrier to successful transplantation outcomes. Recent studies have shown that pharmacotherapy for GVHD should target both the innate and adaptive inflammatory immune responses. Juglone, a redox-active phytochemical found in walnuts, has shown potent anti-inflammatory effects in models of colitis and inflammatory bowel disease. However, its effects on T-cell-mediated immune responses remain largely unknown. Considering the overlapping mediators of inflammation in GVHD and the aforementioned conditions, we investigated the use of juglone as a prophylactic agent for GVHD.

EXPERIMENTAL APPROACH

Immunomodulatory activity and mechanism of action of juglone were studied using murine splenic leukocytes in vitro. The GVHD prophylactic efficacy of orally administered juglone was evaluated using a murine model of allogeneic haematopoietic stem cell transplantation based on an MHC mismatch.

KEY RESULTS

Juglone exhibited immunomodulatory activity by (i) inhibiting the activation of dendritic cells and CD4+ T-cells, (ii) inhibiting cytokine secretion and lymphocyte proliferation, and (iii) inducing exhaustion of CD4+ T-cells, as shown by increased expression of CTLA-4 (CD152) and Fas (CD95). Oral administration of juglone significantly reduced mortality and morbidity associated with GVHD while maintaining graft-versus-leukaemia activity. This was accompanied by a decrease in the number of naïve CD4+ cells, and an increase in the number of CD4+ and CD8+ central memory T-cells.

CONCLUSION AND IMPLICATIONS

Juglone is a potent immunomodulator for GVHD prophylaxis. Our study is the first to provide a dosage framework for the oral administration of juglone that can be used for clinical development.

γ-Tocotrienol induces apoptosis in human T cell lymphoma through activation of both intrinsic and extrinsic pathways

Tocotrienols are members of vitamin E family and possess broad biological activities including antioxidant, anti-inflammatory and antitumor effects. In the present study, we examine the potential of α-tocotrienol (AT) and γ-tocotrienol (GT) in inhibiting the proliferation of human T cell lymphoma Jurkat cells and elucidate the pathways involved in anti tumor effects of GT. GT but not AT inhibited proliferation and induced apoptosis in Jurkat cells in a dose dependent manner. GT treatment resulted in elevated mitochondrial ROS production, activation of JNK and suppression of ERK and p38 MAPK. GT also induced calcium release, loss of mitochondrial membrane potential and cytochrome c release from the mitochondria. These changes were accompanied by increase in Bax expression with a concomitant decrease in Bcl-xl expression suggesting activation of mitochondrial apoptotic pathway. GT induced increase in mitochondrial ROS was abrogated by catalase. Besides, GT also up-regulated surface expression of Fas and FasL on Jurkat cells. Further, caspase activation and PARP degradation were also seen in cells treated with GT. Inhibitors of caspase-8 and caspase-9 significantly abrogated GT mediated apoptosis. In contrast GT was not toxic to normal human peripheral blood mononuclear cells suggesting differential cytotoxicity towards normal lymphocytes and transformed lymphoma cells. Cellular uptake studies with tocotrienols showed higher intracellular accumulation of GT as compared to AT which may be responsible for its better antitumor activity. Our results show antitumor effects of GT in human lymphoma cells via increased mitochondrial ROS generation and activation of both intrinsic and extrinsic apoptotic pathways.

Role of immunoregulatory transcription factors in differential immunomodulatory effects of tocotrienols

Tocotrienols have been shown to possess antioxidant, antitumor, cardioprotective, and antiproliferative effects. This report describes novel immunomodulatory effects of tocotrienols in murine lymphocytes. γ-Tocotrienol (GT) was more effective in suppressing concanavalin A (Con A)-induced T cell proliferation and cytokine production compared to α-tocotrienol (AT) when present continuously in the culture. GT inhibited T cell activation markers and costimulatory molecule. GT modulated intracellular glutathione in lymphocytes, and the suppressive effects of GT could not be abrogated by thiol or nonthiol antioxidants, indicating a poor link between anti-inflammatory properties of tocotrienols and cellular redox status. It was also observed that GT suppressed Con A-induced activation of NF-κB, AP-1, and NF-κB-dependent gene expression. Cellular uptake studies with tocotrienols showed higher accumulation of GT compared to AT. Similar immunosuppressive effects of GT were also observed when administered to mice. In contrast, transient exposure of lymphocytes to GT (4 h) resulted in higher survival and proliferation of lymphocytes in vitro and in vivo in syngeneic and allogeneic hosts. This was attributed to the ability of GT to induce NF-κB, AP-1, and mTOR activation in lymphocytes upon transient exposure. Our results demonstrated that antioxidants such as tocotrienols may exhibit pleiotropic effects by activating multiple mechanisms in cells.

A randomized, double-blind, placebo-controlled, dose ranging study to assess the efficacy and safety of eltrombopag in patients receiving carboplatin/paclitaxel for advanced solid tumors

OBJECTIVES

Eltrombopag, an oral, nonpeptide thrombopoietin receptor agonist, has been shown to increase platelet counts in adults with chronic immune thrombocytopenia and chronic hepatitis C. This multicenter phase 2 study assessed the efficacy and safety of eltrombopag in patients receiving first-line carboplatin/paclitaxel for the treatment of advanced solid tumors.

RESEARCH DESIGN AND METHODS

Patients (N = 183) were randomized to placebo or eltrombopag 50 mg, 75 mg, or 100 mg given orally following chemotherapy on days 2 through 11 of each 21-day cycle, for at least two cycles. The primary endpoint was the difference in platelet count from day 1 in cycle 2 to the platelet nadir in cycle 2.

CLINICAL TRIAL REGISTRY NUMBER

NCT00102726.

RESULTS

Although the primary endpoint was not met, postnadir platelet counts increased during cycles 1 and 2 in all eltrombopag treatment groups compared with placebo. The most commonly reported adverse events across all study arms (including placebo) were nausea and alopecia and eltrombopag was generally well tolerated.

CONCLUSIONS

This study provides preliminary information that eltrombopag does increase platelets in patients receiving chemotherapy for advanced solid tumors. Further investigation is needed to identify the optimal dose(s) and schedule of eltrombopag in patients receiving myelosuppressive chemotherapy.

Computer simulation and tank experimental verification of concentric ring electrodes

Brain activity generates electrical potentials that are spatio-temporal in nature. EEG is the least costly and most widely used non-invasive technique for diagnosing many problems related to the brain. It has very good temporal resolution, but does not poses high spatial resolution primarily due to the blurring affects of the volume conductor. The surface Laplacian enhances the spatial resolution and selectivity of the surface electrical activity as it takes the second spatial derivative of the potential. In an attempt to increase the localization and spatial selectivity a five point finite difference method has recently been used in a bipolar electrode configuration. Here we report on a nine point finite difference method as a model for the tripolar electrode configuration. We have designed a computer simulation to model electrode properties and a dipole at various depths below the electrode surface. A tank experimental was setup to verify the computer simulated potentials. In the simulation and tank experiment, a concentric ring electrode of 2 cm diameter was used. We found that the tripolar electrode configuration has significantly better localization and signal to noise ratio than the bipolar and quasi-bipolar configurations.

Histological appearance of a chronically stimulated vagus nerve in a pediatric patient

Histological analysis of chronically stimulated human vagus nerves is lacking in the literature. In this study, we describe the first microscopic findings in a chronically stimulated left vagus nerve from a pediatric patient. Our results show many histological changes in and around the stimulated nerve with severe demyelination. Further long-term clinical and postmortem examinations of chronically stimulated vagus nerves in both children and adults are needed to ascertain whether prolonged exposure to electrical current can cause clinical dysfunction of this nerve.

Once- and twice-daily dosing with rosiglitazone improves glycemic control in patients with type 2 diabetes

OBJECTIVE

To determine the efficacy of rosiglitazone compared with placebo in reducing hyperglycemia.

RESEARCH DESIGN AND METHODS

After a 4-week placebo run-in period, 959 patients were randomized to placebo or rosiglitazone (total daily dose 4 or 8 mg) for 26 weeks. The primary measure of efficacy was change in the HbA1c concentration.

RESULTS

Rosiglitazone produced dosage-dependent reductions in HbA1c of 0.8, 0.9, 1.1, and 1.5% in the 4 mg o.d., 2 mg b.i.d., 8 mg o.d., and 4 mg b.i.d. groups, respectively, compared with placebo. Clinically significant decreases from baseline in HbA1c were observed in drug-naive patients at all rosiglitazone doses and in patients previously treated with oral monotherapy at rosiglitazone 8 mg o.d. and 4 mg b.i.d. Clinically significant decreases from baseline in HbA1c were also observed with rosiglitazone 4 mg b.i.d. in patients previously treated with combination oral therapy. Approximately 33% of drug-naive patients treated with rosiglitazone achieved HbA1c < or =7% at study end. The proportions of patients with at least one adverse event were comparable among the rosiglitazone and placebo groups. There was no evidence of hepatotoxicity in any treatment group. There were statistically significant increases in weight and serum lipids in all rosiglitazone treatment groups compared with placebo. For LDL and HDL cholesterol, the observed increase appeared to be dose related.

CONCLUSIONS

Rosiglitazone at total daily doses of 4 and 8 mg significantly improved glycemic control in patients with type 2 diabetes and was well tolerated.

Rosiglitazone monotherapy is effective in patients with type 2 diabetes

This study evaluated the efficacy and safety of rosiglitazone monotherapy in patients with type 2 diabetes. After a 4-week placebo run-in period, 493 patients with type 2 diabetes were randomized to receive rosiglitazone [2 or 4 mg twice daily (bd)] or placebo for 26 weeks. The primary end point was change in hemoglobin A(1c); other variables assessed included fasting plasma glucose, fructosamine, endogenous insulin secretion, urinary albumin excretion, serum lipids, and adverse events. Rosiglitazone (2 and 4 mg bd) decreased mean hemoglobin A(1c) relative to placebo by 1.2 and 1.5 percentage points, respectively, and reduced fasting plasma glucose concentrations relative to placebo by 3.22 and 4.22 mmol/L, respectively. Fasting plasma insulin and insulin precursor molecules decreased significantly. Homeostasis model assessment estimates indicate that rosiglitazone (2 and 4 mg bd) reduced insulin resistance by 16.0% and 24.6%, respectively, and improved ss-cell function over baseline by 49.5% and 60.0%, respectively. Urinary albumin excretion decreased significantly in the rosiglitazone (4 mg bd) group. There was no increase in adverse events with rosiglitazone. In the short-term, rosiglitazone is an insulin sensitizer that is effective and safe as monotherapy in patients with type 2 diabetes who are inadequately controlled by lifestyle interventions.

Effect of metformin and rosiglitazone combination therapy in patients with type 2 diabetes mellitus: a randomized controlled trial

CONTEXT

Most antidiabetic agents target only 1 of several underlying causes of diabetes. The complementary actions of the antidiabetic agents metformin hydrochloride and rosiglitazone maleate may maintain optimal glycemic control in patients with type 2 diabetes; therefore, their combined use may be indicated for patients whose diabetes is poorly controlled by metformin alone.

OBJECTIVE

To evaluate the efficacy of metformin-rosiglitazone therapy in patients whose type 2 diabetes is inadequately controlled with metformin alone.

DESIGN

Randomized, double-blind, placebo-controlled trial from April 1997 and March 1998.

SETTING

Thirty-six outpatient centers in the United States.

PATIENTS

Three hundred forty-eight patients aged 40 to 80 years with a mean fasting plasma glucose level of 12.0 mmol/L (216 mg/dL), a mean glycosylated hemoglobin level of 8.8%, and a mean body mass index of 30.1 kg/m2 were randomized.

INTERVENTIONS

Patients were assigned to receive 2.5 g/d of metformin plus placebo (n = 116); 2.5 g/d of metformin plus 4 mg/d of rosiglitazone (n = 119); or 2.5 g/d of metformin and 8 mg/d of rosiglitazone (n = 113) for 26 weeks.

MAIN OUTCOME MEASURES

Glycosylated hemoglobin levels, fasting plasma glucose levels, insulin sensitivity, and beta-cell function, compared between baseline and week 26, by treatment group.

RESULTS

Glycosylated hemoglobin levels, fasting plasma glucose levels, insulin sensitivity, and beta-cell function improved significantly with metformin-rosiglitazone therapy in a dose-dependent manner. The mean levels of glycosylated hemoglobin decreased by 1.0% in the 4 mg/d metformin-rosiglitazone group and by 1.2% in the 8 mg/d metformin-rosiglitazone group and fasting plasma glucose levels by 2.2 mmol/L (39.8 mg/dL) and 2.9 mmol/L (52.9 mg/dL) compared with the metformin-placebo group (P<.001 for all). Of patients receiving 8 mg/d of metformin-rosiglitazone, 28.1% achieved a glycosylated hemoglobin level of 7% or less [corrected]. Dose-dependent increases in body weight and total and low-density lipoprotein cholesterol levels were observed (P<.001 for both rosiglitazone groups vs placebo). The proportion of patients reporting adverse experiences was comparable across all groups.

CONCLUSIONS

Our data suggest that combination treatment with once-daily metformin-rosiglitazone improves glycemic control, insulin sensitivity, and beta-cell function more effectively than treatment with metformin alone.

Rosiglitazone taken once daily provides effective glycaemic control in patients with Type 2 diabetes mellitus

AIMS

To evaluate the clinical efficacy and safety of rosiglitazone as a once daily treatment for Type 2 diabetes mellitus (DM).

METHODS

Three hundred and sixty-nine patients with Type 2 DM (mean age 63 years; mean body mass index (BMI) 29.4 kg/m2) were enrolled in a double-blind, parallel group, placebo-controlled, dose-ranging study. Patients were randomly assigned to receive placebo or rosiglitazone at doses of 4, 8, or 12 mg daily for 8 weeks.

RESULTS

At 8 weeks, fasting plasma glucose (FPG) decreased significantly in the rosiglitazone 4 mg, 8 mg, and 12 mg groups (-0.9, -2.0 and -1.7 mmol/l; P = 0.0003, < 0.0001, and < 0.0001, respectively) compared with placebo (+0.4 mmol/l). The improvements in FPG were dose ordered for 4 and 8 mg/ day. The 12 mg/day dose produced no additional improvement. There were small decreases in haemoglobin and haematocrit in the rosiglitazone treatment groups. The overall incidence of adverse experiences was similar in all treatment groups, including placebo with no evidence of hypoglycaemia or hepatotoxicity.

CONCLUSIONS

Rosiglitazone improves glycaemic control when given once daily to treat Type 2 diabetes mellitus and is well tolerated at doses up to and including 12 mg.

Rosiglitazone short-term monotherapy lowers fasting and post-prandial glucose in patients with type II diabetes

AIMS/HYPOTHESIS

The short-term efficacy, safety and tolerability of rosiglitazone were compared with placebo in patients with Type II (non-insulin-dependent) diabetes mellitus in a dose-ranging study.

METHODS

After a 2-week placebo run-in phase, 303 patients were randomly assigned to 8 weeks of treatment with twice-daily placebo or 2, 4 or 6 mg of rosiglitazone.

RESULTS

All rosiglitazone doses significantly reduced fasting plasma glucose compared with baseline. All rosiglitazone treatment groups showed significantly reduced peak postprandial glucose concentrations compared with baseline (p < 0.001) and with placebo (p < 0.0001) and reduced postprandial glucose excursion, without an increase in the area under the postprandial insulin concentration-time curve. Rosiglitazone at 4 and 6 mg twice daily prevented the increase in HbA1c observed in the placebo group. C peptide and serum insulin concentrations were significantly reduced from baseline in all rosiglitazone treatment groups. In all rosiglitazone treatment groups, nonesterified fatty acids decreased significantly (p < 0.0001) and triglycerides did not change. Although total LDL and HDL cholesterol increased significantly in the rosiglitazone treatment groups, total cholesterol/HDL ratios did not change significantly. The proportion of patients with one or more adverse event was similar in all four treatment groups. No patient showed evidence of hepatotoxicity.

CONCLUSION/INTERPRETATION

Rosiglitazone given twice daily significantly reduced fasting and postprandial glucose concentrations, C peptide, insulin and nonesterified fatty acids in Type II diabetic patients. The glucose-lowering effect of the 4-mg twice-daily dose of rosiglitazone was similar to that of 6-mg twice daily, suggesting that 4 mg twice daily should be the maximum clinical dose.

Hepatotoxic reactions associated with carbamazepine therapy

Hepatotoxic reactions in patients receiving carbamazepine (CBZ) therapy have been reported, and some have been considered fatal. We present two patients with hepatic dysfunction secondary to CBZ therapy. Liver biopsies were compatible with hepatotoxic damage, and the symptoms were reversible with medication withdrawal. Our patients are representative of those in the literature, most of whom have granulomatous hepatitis and sometimes have associated cholangitis. The patients with fatal reactions differed clinically and pathologically from the others, and may represent a different entity. The clinical syndrome resembles a viral hepatitis. Elderly patients seem to be particularly susceptible and their hepatic function should be monitored closely when CBZ therapy is initiated.

Stereoselective metabolism and pharmacogenetic control of 5-phenyl-5-ethylhydantoin (nirvanol) in humans

Aromatic hydroxylation of 5-phenyl-5-ethylhydantoin (PEH) has been investigated in humans. Single oral doses of S-PEH (247 mumol) were given to seven extensive and seven poor hydroxylators of mephenytoin. Urinary recovery of PEH and 5-(4-hydroxyphenyl)-5-ethylhydantoin (4-OH-PEH) indicated that all extensive metabolizer subjects excreted appreciable quantities of 4-OH-PEH, whereas all poor metabolizer subjects had only trace amounts of 4-OH-PEH in their urine. Four extensive metabolizer subjects received dual radiolabeled (S-[14C]PEH, R-[3H]PEH) pseudoracemic (494 mumol R-PEH, 494 mumol S-PEH) PEH and had serial urine and blood samples collected over 16 days. The urinary excretion rates of S-PEH and S-4-OH-PEH had half-lives of approximately 4.5 days whereas those of R-PEH and R-4-OH-PEH were approximately 10 days. The initial S/R ratio of 4-OH-PEH in urine was 14:1 whereas that of PEH was 1:1. Stereoselective hydroxylation in these four subjects was confirmed by the negligible recovery of 4-OH-PEH after oral administration of R-PEH (494 mumol). After racemic administration, the sum of S-and R-PEH plasma concentrations declined biexponentially with half-lives of the alpha- and beta-phases being consistent with the total plasma concentration reflecting the sum of the different rates of elimination of the two enantiomers. These results are consistent with the hypothesis that the same drug metabolizing enzymes are involved in the aromatic hydroxylation of S-mephenytoin and S-PEH.

Mephenytoin hydroxylation deficiency: kinetics after repeated doses

Deficient aromatic hydroxylation of S-mephenytoin was observed in an index subject during a kinetic study of stereoselective metabolism of mephenytoin. A genetic basis for this defect was suggested by decreased urinary recovery of 3-methyl-5-(4-hydroxyphenyl)-5-ethylhydantoin (4-OH-M) in the 24 hr after oral racemic mephenytoin in two brothers of the propositus. The parents and a third brother had urinary recoveries of 4-OH-M of the same order as in a group of 20 normal subjects. The kinetic implications of this defect were studied in the index subject and compared with four normal subjects after a single oral dose of differentially radiolabeled pseudoracemic mephenytoin (5 microCi of 14C-S-mephenytoin, 45 microCi of H3-R-mephenytoin, and 11.5 mumol/kg of both S- and R-mephenytoin) followed by single oral doses of 1.4 mmol of unlabeled racemic mephenytoin daily the next 4 days. In normal subjects, there was substrate stereoselective metabolism with the S-enantiomer rapidly excreted as 4-OH-M and the R-enantiomer slowly excreted as 5-phenyl-5-ethylhydantoin (PEH). Stereoselective metabolism persisted during repeated dosing. In the hydroxylation-deficient subject, there was no evidence of stereoselective metabolism, recovery of 4-OH-M was low, and both enantiomers were slowly excreted, predominantly as PEH. Plasma PEH concentrations and urinary PEH excretion rates were approximately twice that in normal subjects. Thus a genetic deficiency in ability to hydroxylate S-mephenytoin results in the S-enantiomer metabolization by the alternate route of demethylation to PEH that cumulates, thereby, in comparison to the normal, effectively doubling the dose of total hydantoin.

Fetal alcohol syndrome: inhibition of placental zinc transport as a potential mechanism for fetal growth retardation in the rat

Growth retardation is one of the principal features of fetal alcohol syndrome. The cause of this growth retardation is unknown. Because of the clinical similarities between fetal alcohol syndrome and prenatal zinc deficiency, we studied in vivo the effect of short-term and long-term ethanol ingestion during pregnancy on placental transport of zinc in pair-fed rats. Our results indicate that both short- and long-term ethanol depressed zinc-65 uptake in the placenta and fetus by 40% and 30%, respectively, compared to pair-fed controls (p less than 0.05). Total zinc concentration in fetuses of the long-term ethanol group was significantly decreased compared to pair-fed controls (p less than 0.05). Although the mechanism of action of ethanol in producing the fetal alcohol syndrome maybe multiple, our findings suggest that a decrease in the availability of zinc to the fetus may represent one of the contributory factors in the growth retardation of fetal alcohol syndrome.

Intestinal calcium transport: effect of cimetidine

Recently cimetidine (Tagamet), a widely used drug for peptic ulcer disease, was found to decrease serum levels of calcium and immunoreactive parathyroid hormone in patients with hyperparathyroidism. Since parathyroid hormone action is closely related to calcium homeostasis, we studied the effect of cimetidine on intestinal calcium transport. An in vivo perfusion technique was used for the study of net transport and lumen to mucosa flux of 45calcium. Our results indicate a significant decrease in net calcium transport and lumen to mucosa flux of 45calcium in the rats injected with cimetidine, compared to control rats. Direct addition of cimetidine to the perfusion solution did not alter transport rates significantly. The mechanism by which cimetidine affects calcium transport may be secondary to its effect on the release of parathyroid hormone from the parathyroid gland or an effect on vitamin D metabolism.

Effect of short-term ethanol administration on lorazepam clearance

The disposition of chlordiazepoxide (Librium) and diazepam (Valium), compounds which are initially degraded by oxidative processes, differs from that of oxazepam (Serax) and lorazepam (Ativan, drugs which are inactivated by conjugation with glucuronic acid. Liver disease and cimetidine impair the elimination of the former agents, but not the latter two benzodiazepines. In addition, ethanol inhibits the metabolism of chlordiazepoxide and diazepam. The present studies were performed to determine the effect of short-term ethanol administration on glucuronidation and elimination of lorazepam in dogs and humans. Because, in dogs, lorazepam has a high extraction ratio (approximately 0.9) with an anticipated large presystemic elimination, the influence of ethanol on the presystemic (first-pass) elimination of lorazepam was determined. Administration of p.o. lorazepam to five healthy dogs 1 hr after i.v. saline or ethanol (3 gm/kg) reduced the presystemic elimination of lorazepam by 52% (p less than 0.05). In man, lorazepam has a low (approximately by 0.05) extraction ratio and only a small first-pass effect. Short-term administration of ethanol (0.8 gm/kg followed by 0.5 gm/kg p.o. every 5 hr for four doses) reduced i.v. lorazepam clearance by 18% (p less than 0.03). In dogs and man, ethanol did not significantly alter lorazepam t1/2, plasma protein binding, or distribution volume (Vd beta). The results suggest that short-term ethanol administration impairs the conjugation of lorazepam in dogs and man.