The effects of myo-inositol and probiotic supplementation in a high-fat-fed preclinical model of glucose intolerance in pregnancy.

Glucose intolerance during pregnancy - a major driver of gestational diabetes mellitus (GDM) - has significant short- and long-term health consequences for both the mother and child. As GDM prevalence continues to escalate, there is growing need for preventative strategies. There is limited but suggestive evidence that myo-inositol (MI) and probiotics (PB) could improve glucose tolerance during pregnancy. The present study tested the hypothesis that MI and/or PB supplementation would reduce the risk of glucose intolerance during pregnancy. Female C57BL/6 mice were randomised to receive either no treatment, MI, PB (Lactobacillus rhamnosus and Bifidobacterium lactis) or both (MIPB) for 5 weeks. They were then provided with a high-fat diet for 1 week before mating commenced and throughout mating/gestation, while remaining on their respective treatments. An oral glucose tolerance test occurred at gestational day (GD) 16·5 and tissue collection at GD 18·5. Neither MI nor PB, separately or combined, improved glucose tolerance. However, MI and PB both independently increased adipose tissue expression of Ir, Irs1, Akt2 and Pck1, and PB also increased Pparγ. MI was associated with reduced gestational weight gain, whilst PB was associated with increased maternal fasting glucose, total cholesterol and pancreas weight. These results suggest that MI and PB may improve insulin intracellular signalling in adipose tissue but this did not translate to meaningful differences in glucose tolerance. The absence of fasting hyperglycaemia or insulin resistance suggests this is a very mild model of GDM, which may have affected our ability to assess the impact of these nutrients.

Low incidence of anti-drug antibodies in patients with type 2 diabetes treated with once-weekly glucagon-like peptide-1 receptor agonist dulaglutide.

Therapeutic administration of peptides may result in anti-drug antibody (ADA) formation, hypersensitivity adverse events (AEs) and reduced efficacy. As a large peptide, the immunogenicity of once-weekly glucagon-like peptide-1 (GLP-1) receptor agonist dulaglutide is of considerable interest. The present study assessed the incidence of treatment-emergent dulaglutide ADAs, hypersensitivity AEs, injection site reactions (ISRs), and glycaemic control in ADA-positive patients in nine phase II and phase III trials (dulaglutide, N = 4006; exenatide, N = 276; non-GLP-1 comparators, N = 1141). Treatment-emergent dulaglutide ADAs were detected using a solid-phase extraction acid dissociation binding assay. Neutralizing ADAs were detected using a cell-based assay derived from human endothelial kidney cells (HEK293). A total of 64 dulaglutide-treated patients (1.6% of the population) tested ADA-positive versus eight (0.7%) from the non-GLP-1 comparator group. Of these 64 patients, 34 (0.9%) had dulaglutide-neutralizing ADAs, 36 (0.9%) had native-sequence GLP-1 (nsGLP-1) cross-reactive ADAs and four (0.1%) had nsGLP-1 neutralization ADAs. The incidence of hypersensitivity AEs and ISRs was similar in the dulaglutide versus placebo groups. No dulaglutide ADA-positive patient reported hypersensitivity AEs. Because of the low incidence of ADAs, it was not possible to establish their effect on glycaemic control.

Steady-state pharmacokinetics and glucodynamics of the novel, long-acting basal insulin LY2605541 dosed once-daily in patients with type 2 diabetes mellitus.

AIMS: To assess the pharmacokinetics (PK) and glucodynamics (GD) of LY2605541 in patients with type 2 diabetes mellitus. METHODS: This parallel-group, open-label, dose-escalation study examined the PK and GD of basal insulin LY2605541 after single and multiple-dose administration. Fixed doses of LY2605541 (0.33-1.00 U/kg) were given once-daily (QD) for 14 days to insulin-treated patients with type 2 diabetes. A 24-h euglycaemic glucose clamp was conducted on days 1 and 14. RESULTS: PK steady state was achieved within 7-10 days and the peak-to-trough fluctuation was <2, translating to a nearly 'peakless' glucose infusion rate at steady state and with a duration of action of at least 24 h. Across dose levels t1/2 ranged from 44.7 to 75.5 h (~2-3 days). As steady state was achieved, there were dose-dependent reductions in the prandial insulin dose and in fasting blood glucose, which decreased to 60-100 mg/dl across dose levels. Within-patient variability was <14 and <26% for the area under the concentration versus time curve (AUC) of the 8-point blood glucose profile and fasting blood glucose, respectively. The nocturnal glucose control between 03:00 and 09:00 hours was relatively unchanged. Mild hypoglycaemia was the most common adverse event. CONCLUSIONS: In this Phase I study of fixed LY2605541 doses without titration, LY2605541 was well-tolerated and demonstrated a flat PK and GD profile accompanied by glucose normalization, prandial insulin dose reduction and no severe hypoglycaemia.

Clinical relevance of anti-exenatide antibodies: safety, efficacy and cross-reactivity with long-term treatment.

AIMS: Antibody formation to therapeutic peptides is common. This analysis characterizes the time-course and cross-reactivity of anti-exenatide antibodies and potential effects on efficacy and safety. METHODS: Data from intent-to-treat patients in 12 controlled (n = 2225,12-52 weeks) and 5 uncontrolled (n = 1538, up to 3 years) exenatide twice-daily (BID) trials and 4 controlled (n = 653,24-30 weeks) exenatide once weekly (QW) trials with 1 uncontrolled period (n = 128,52 weeks) were analysed. RESULTS: Mean titres peaked early (6-22 weeks) and subsequently declined. At 30 weeks, 36.7% of exenatide BID patients were antibody-positive; 31.7% exhibited low titres (≤125) and 5.0% had higher titres (≥625). Antibody incidence declined to 16.9% (1.4% higher titre) at 3 years. Similarly, 56.8% of exenatide QW patients were antibody-positive (45.0% low/11.8% higher titre) at 24-30 weeks, declining to 45.4% positive (9.2% higher titre) at 52 weeks. Treatment-emergent anti-exenatide antibodies from a subset of patients tested did not cross-react with human GLP-1 or glucagon. Other than injection-site reactions, adverse event rates in antibody-positive and antibody-negative patients were similar. Efficacy was robust in both antibody-negative and antibody-positive patients (mean HbA1c change: -1.0 and -0.9%, respectively, exenatide BID; -1.6% and -1.3% exenatide QW). No correlation between change in HbA1c and titre was observed for exenatide BID, although mean reductions were attenuated in the small subset of patients (5%) with higher titres. A significant correlation was observed for exenatide QW with no difference between antibody-negative and low-titre patients, but an attenuated mean reduction in the subset of patients (12%) with higher titres. CONCLUSIONS: Low-titre anti-exenatide antibodies were common with exenatide treatment (32% exenatide BID, 45% exenatide QW patients), but had no apparent effect on efficacy. Higher-titre antibodies were less common (5% exenatide BID, 12% exenatide QW) and within that titre group, increasing antibody titre was associated with reduced average efficacy that was statistically significant for exenatide QW. Other than injection-site reactions, anti-exenatide antibodies did not impact the safety of exenatide.

Development of a new peptide-bead coupling method for an all peptide-based Luminex multiplexing assay for detection of Plasmodium falciparum antibody responses.

Using a recombinant protein antigen for antibody testing shows a sum of antibody responses to multiple different immune epitopes existing in the protein antigen. In contrast, the antibody testing to an immunogenic peptide epitope reflects a singular antibody response to the individual peptide epitope. Therefore, using a panel of peptide epitopes provides an advantage for profiling multiple singular antibody responses with potential to estimate recent malaria exposure in human infections. However, transitioning from malaria immune epitope peptide-based ELISA to an all peptide bead-based multiplex Luminex assay presents some challenges including variation in the ability of different peptides to bind beads. The aim of this study was to develop a peptide coupling method while demonstrating the utility of these peptide epitopes from multiple stage antigens of Plasmodium falciparum for measuring antibodies. Successful coupling of peptide epitopes to beads followed three steps: 1) development of a peptide tag appended to the C-terminus of each peptide epitope consisting of beta-alanine-lysine (x 4)--cysteine, 2) bead modification with a high concentration of adipic acid dihydrazide, and 3) use of the peptide epitope as a blocker in place of the traditional choice, bovine serum albumin (BSA). This new method was used to couple 12 peptide epitopes from multiple stage specific antigens of P. falciparum, 1 Anopheles mosquito salivary gland peptide, and 1 Epstein-Barr virus peptide as an assay control. The new method was applied to testing of IgG in pooled samples from 30 individuals with previously repeated malaria exposure in western Kenya and IgM and IgG in samples from 37 U.S. travelers with recent exposure to malaria. The new peptide-bead coupling method and subsequent multiplex Luminex assay showed reliable detection of IgG to all 14 peptides in Kenyan samples. Among 37 samples from U.S. travelers recently diagnosed with malaria, IgM and IgG to the peptide epitopes were detected with high sensitivity and variation. Overall, the U.S. travelers had a much lower positivity rates of IgM than IgG to different peptide epitopes, ranging from a high of 62.2% positive for one epitope to a low of only 5.4% positive for another epitope. In contrast, the travelers had IgG positive rates from 97.3% to 91.9% to various peptide epitopes. Based on the different distribution in IgM and IgG positivity to overall number of peptide epitopes and to the number of pre-erythrocytic, erythrocytic, gametocytic, and salivary stage epitopes at the individual level, four distinct patterns of IgM and IgG responses among the 37 samples from US travelers were observed. Independent peptide-bead coupling and antibody level readout between two different instruments also showed comparable results. Overall, this new coupling method resolves the peptide-bead coupling challenge, is reproducible, and can be applied to any other immunogenic peptide epitopes. The resulting all peptide bead-based multiplex Luminex assay can be expanded to include other peptide epitopes of P. falciparum, different malaria species, or other diseases for surveillance, either in US travelers or endemic areas.

Six weeks' sebacic acid supplementation improves fasting plasma glucose, HbA1c and glucose tolerance in db/db mice.

AIM: To investigate the impact of chronic ingestion of sebacic acid (SA), a 10-carbon medium-chain dicarboxylic acid, on glycaemic control in a mouse model of type 2 diabetes (T2D). METHODS: Three groups of 15 db/db mice were fed for 6 weeks either a chow diet (Ctrl) or a chow diet supplemented with 1.5 or 15% (SA(1.5%) and SA(15%) , respectively) energy from SA. Fasting glycaemia was measured once a week and HbA1c before and after supplementation. An oral glucose tolerance test (OGTT) was performed at the end of the supplementation. Gene expression was determined by transcriptomic analysis on the liver of the Ctrl and SA(15%) groups. RESULTS: After 42 days of supplementation, fasting glycaemia and HbA1c were ∼70 and 25% lower in the SA(15%) group compared with the other groups showing a beneficial effect of SA on hyperglycaemia. During OGTT, plasma glucose area under the curve was reduced after SA(15%) compared with the other groups. This effect was associated with a tendency for an improved insulin response. In the liver, Pck1 and FBP mRNA were statistically decreased in the SA(15%) compared with Ctrl suggesting a reduced hepatic glucose output induced by SA. CONCLUSION: Dietary supplementation of SA largely improves glycaemic control in a mouse model of T2D. This beneficial effect may be due to (i) an improved glucose-induced insulin secretion and (ii) a reduced hepatic glucose output.

The effect of exenatide on lisinopril pharmacodynamics and pharmacokinetics in patients with hypertension.

OBJECTIVES: This study evaluated the potential effect of exenatide on the pharmacokinetics and pharmacodynamics of lisinopril in patients with mild-to-moderate hypertension. METHODS: 22 patients with mild-to-moderate primary hypertension participated in a double-blind, randomized, placebo-controlled, 2-period, 2-sequence crossover study. Patients on stable lisinopril therapy were randomly assigned to receive subcutaneous exenatide (10 microg b.i.d.) and placebo b.i.d. separated by at least 2 days washout period. The primary pharmacodynamic parameters were baseline-adjusted 24-hour mean systolic and diastolic blood pressure. Steady state plasma lisinopril concentration-time profiles were also assessed. RESULTS: Mean blood pressure changes were not significantly different between exenatide and placebo coadministered with lisinopril. The least squares mean differences (95% CI) between treatments were +1.38 mmHg (-1.41, 4.17) for diastolic and +1.38 mmHg (-1.95, 4.71) for systolic blood pressure. Exenatide delayed the time to attain maximum lisinopril concentration (tmax,ss) by 2 hours but did not significantly alter maximum lisinopril concentration (Cmax,ss) or area under the concentration-time profile (AUCtau,ss) over the 24-hour steady-state dosing interval. CONCLUSIONS: This study demonstrated that concurrent administration of exenatide did not produce clinically relevant changes in blood pressure and did not significantly alter lisinopril pharmacokinetics in patients with mild-to-moderate hypertension.

Time course and dynamics of adipose tissue development in obese and lean Zucker rat pups.

OBJECTIVE: To evaluate the ontogeny of adipose tissue dynamics in obese and lean Zucker rat pups, from suckling to puberty. METHODS: The trial had a two-group parallel design. Sixty-two male Zucker rat pups shared within 15 litters received deuterated water for 5 days, prior killing at different age. Adipose tissues were collected for (2)H-enrichment analyses using mass spectrometry to determine fat cell proliferation and lipid synthesis rates. Rats were assigned to obese and lean rat groups by genotyping. RESULTS: The time course (from days 13 to 55) of all adipose tissue growth showed that the highest fractional rates of fat cell proliferation, triacylglycerol (TG) synthesis and de novo lipogenesis (DNL) took place during early suckling in all rat pups. The appearance of excessive fat mass growth in the obese rats, as compared with lean rats, was first shown through a significant increase in DNL at the end of suckling (P<0.05). The TG synthesis rate was enhanced (P<0.05) from the end of suckling and early postweaning until day 55 (from 122+/-10 to 498+/-78 in obese pups and from 25+/-6 to 75+/-26 mg new TG per day in lean pups (median+/-s.e.m., P<0.01)). In contrast, only by day 55 did the fractional proliferation rate of fat cells in retroperitoneal and epididymal depots in the obese rats supersede that of the lean rats (P<0.05). CONCLUSION: The early suckling period constitutes the most active period for adipose tissue development in normal rats. In the obese Zucker rat model, adipose hypertrophy primarily contributes to the early onset of obesity, while hyperplasia increases after puberty. Early onset of adipose tissue growth may play a determinant role in the development of obesity later in life.

Contribution of mesothelial cells in the expression of inflammatory-related factors in omental adipose tissue of obese subjects.

OBJECTIVE: The objective of this study was to determine the contribution of mesothelial cells, present in human omental adipose tissue (OAT) but not in the subcutaneous depot (SAT), on the expression of inflammation-related factors. DESIGN: Comparison of the expression profiles of inflammation-related genes in mesothelial cells with those in the adipocyte-enriched (AEF) and stromal vascular fractions (SVF) and localization of interleukin-18 (IL-18) expression in adipose depots. SUBJECTS: Eleven obese Caucasian female subjects undergoing gastric bypass surgery (body mass index: 43.6+/-1.3 kg/m(2); age: 41.6+/-2.3 years). MEASUREMENTS: The expression profiles of cytokine and chemokine-related genes in mesothelial cells and in cell fractions prepared from OAT were assessed by the microarray technique. The differential expression of IL-18 was confirmed by real-time PCR and the protein was localized in adipose depots by immunohistochemistry. RESULTS: Microarray data analysis demonstrated that, of the 16 cytokine and chemokine-related genes that were upregulated in mesothelial cells compared with the AEF, IL-18 was the cytokine with the highest differential expression. IL-18 expression was similar in mesothelial cells and the SVF. In both SAT and OAT, IL-18 was immunolocalized in neutrophils and mast cells, but not in macrophages nor adipocytes. This cytokine was also detected in mesothelial cells in OAT. This additional source of expression may explain the higher IL-18 expression levels in OAT than SAT (+5.9-fold). CONCLUSION: By their capacity to express inflammatory-related factors, and in particular the proinflammatory cytokine IL-18 in OAT, mesothelial cells appear as a new player in the process of low-grade inflammation associated with obesity.

Exenatide pharmacokinetics in healthy Chinese subjects.

OBJECTIVES: Exenatide is an adjunctive treatment for Type 2 diabetes. This was the first study to evaluate the pharmacokinetics, safety and tolerability of therapeutic doses (5 microg and 10 microg) of exenatide after single and multiple subcutaneous injections in healthy adult Chinese subjects. METHODS: 24 healthy volunteers were randomized to receive either 5 microg or 10 microg of exenatide by subcutaneous injection. Subjects received a single injection of exenatide on Day 1, twice daily on Days 2 and 3, and once on Day 4. Serial blood samples were drawn for pharmacokinetic assessment at pre-dose and up to 12 h post dose on Day 1 and Day 4. Adverse events, vital signs, 12-lead ECG, body weight and clinical laboratory evaluations were assessed. RESULTS: Exenatide, 5 microg and 10 microg, was rapidly absorbed with a median tmax of 1 h after single and multiple doses. Exenatide Cmax and AUCtau,ss were (geometric mean (90% CI)) 145 (119 - 176) pg/ml and 370 (297 - 460) pg x h/ml, respectively, after multiple dosing with 5 microg. The Cmax and AUCtau,ss were 311 (271 - 357) pg/ml and 878 (785 - 983) pg x h/ml, respectively, for 10 microg. Mean half-life (t1/2, range 0.99 - 1.25 h), apparent volume of distribution (Vz/F, 19.2 - 22.3 l), and apparent clearance (CL/F, range 11.4 - 13.5 l/h) remained consistent between single and multiple doses and across the two dose levels. Both the accumulation ratios and linearity index approached 1.0. The most common adverse events were gastrointestinal in nature and mild in severity. The frequency of adverse events increased with dose, such that 8% of subjects who received 5 microg and 42% of subjects who received 10 microg experienced adverse events. CONCLUSIONS: Exenatide was rapidly absorbed, with similar pharmacokinetic properties following single and multiple doses. Exenatide exposure after multiple doses approximately doubled from 5 microg to 10 microg.

Exenatide effects on statin pharmacokinetics and lipid response.

OBJECTIVE: Exenatide is an adjunctive treatment for type 2 diabetes. Many patients with type 2 diabetes have dyslipidemia, which requires treatment with three hydroxy-3-methyl glutaryl coenzyme (HMG-CoA) reductase inhibitors (statins), hence, concurrent use of exenatide and statins is likely. Exenatide slows gastric emptying, which may alter the absorption rate of co-administered oral medications. Thus, the potential interaction between exenatide and statins was evaluated in two study settings. METHODS: In an open-label, fixed-sequence, clinical pharmacology study, the plasma pharmacokinetics of lovastatin (40 mg after breakfast) in the presence and absence of exenatide (10 microg before breakfast and dinner) was evaluated in 21 healthy subjects. In a second clinical setting, changes in lipid profiles and statin dosage over 30 weeks in patients with type 2 diabetes were retrospectively compared (n = 180 exenatide 10 microg twice daily (BID), n = 168 placebo BID) in a combined analysis of three placebo-controlled, randomized exenatide Phase 3 trials. RESULTS: In healthy subjects, exenatide decreased mean lovastatin area under the plasma concentration time curve from zero to infinity (AUC0-infinity) and maximum plasma concentration (Cmax) by 40 and 28%, respectively, and increased median time to maximum plasma concentration (tmax) by 4 hours. In the exenatide Phase 3 trials, 30-week changes from baseline for low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol, triglycerides and statin dosage were not significantly different between the exenatide and placebo groups treated with statins. CONCLUSIONS: Despite observed changes in lovastatin bioavailability in the pharmacokinetic drug interaction study, exenatide did not negatively affect long-term lipid profiles or statin dosage in patients with concurrent statin therapy. Thus, co-administration of exenatide does not require adjustment in statin dosage.

Alterations in murine host defense functions by adriamycin or liposome-encapsulated adriamycin.

Peritoneal exudate cells (PEC) from C57BL/6 mice were collected on different days following an i.p. injection of Adriamycin (10 mg/kg) as free drug (ADM) or encapsulated in multilamellar liposomes (ADM/Lip). Macrophages harvested from mice at various times (Days 4-14) after either drug treatment were responsive to in vitro lipopolysaccharide induction of tumoricidal activity, maximum response being seen on Day 7. In addition, 18 days after treatment, significant macrophage tumoricidal activity was observed only in the ADM/Lip-treated group. When supernatants from cultures of PEC obtained 7 days after treatment were assayed for interleukin 1 following lipopolysaccharide stimulation, activity was found with both ADM- and ADM/Lip-treated cells. Without lipopolysaccharide stimulation, only PEC from ADM-treated mice elaborated factor(s) with interleukin 1-like activity. Both ADM and ADM/Lip induced significant PEC-natural killer (PEC-NK) activity by Day 4, while the ADM/Lip treatment sustained PEC-NK activity more effectively than free drug at later time points (7 or 11 days posttreatment). Drug-induced PEC-NK activity (Day 7) was (a) ablated by treatment in vitro with anti-asialo GM1 antibody and complement, and (b) associated with a population of PEC nonadherent to plastic. A transient suppression of splenic NK activity was seen 4 days following either ADM or ADM/Lip administration with recovery to control level by Day 7. These data demonstrate that following ADM or ADM/Lip administration some of the changes necessary for macrophage tumoricidal activation must have occurred in vivo. Liposome encapsulation of ADM extended the duration of ADM-induced augmentation of certain host defenses.

Effect of recombinant tumor necrosis factor on tumoricidal activation of murine macrophages: synergism between tumor necrosis factor and gamma-interferon.

The activation of tumoricidal murine macrophages by recombinant human tumor necrosis factor (rH-TNF) alone or in combination with recombinant murine gamma-interferon (rM-IFN-gamma) was examined. When used alone, rH-TNF (10(-1)-10(5) units/ml) did not induce macrophage tumoricidal activity against TNF-insensitive P815 mastocytoma cells. Combining rH-TNF with rM-IFN-gamma resulted in the synergistic induction of tumoricidal activity in resident peritoneal macrophages. This synergistic effect was not due to contaminating bacterial lipopolysaccharide. A comparative study using recombinant murine tumor necrosis factor (rM-TNF) showed that rM-TNF alone also could not stimulate murine macrophages and there was no significant difference between effects of rM-TNF and rH-TNF on macrophage activation in the presence of rM-IFN-gamma. In experiments comparing sequential to simultaneous exposure of macrophages to rH-TNF and rM-IFN-gamma, it was found that: (a) when macrophages are primed with rM-IFN-gamma, rH-TNF serves only as a very weak triggering signal for tumoricidal activation; and (b) marked activation is obtained only when macrophages are exposed to the two cytokines simultaneously. These results suggest that TNF has an autocrine regulatory function in concert with lymphokines in macrophage-mediated host defense against tumors.

Modification of host antitumor defense mechanisms in mice by progressively growing tumor.

The EL4 lymphoma in C57BL/6 mice was used as a model to examine the effect of progressive tumor growth on a variety of cell mediated cytolytic effector functions which have been shown in other systems to have antitumor potential. The functions examined were those of cytolytic T-lymphocyte, lymphokine activated killer cells, natural killer cells, and tumoricidal macrophage (MO). The kinetics of each function displayed a unique pattern as a consequence of tumor growth, but all were inhibited in animals bearing large tumors (late tumor bearers). In cell mixing experiments it was shown that spleen cells from individual late tumor bearers were suppressive for cytotoxic T-lymphocytes, lymphokine activated killer cells, and splenic MO but not peritoneal MO or splenic natural killer cells. The suppression was nonspecific and was mediated primarily by nonadherent cells and/or their soluble products. Suppression appeared to be mediated, in part, by tumor cells in the spleen since the degree of suppressor activity associated with a particular spleen cell preparation correlated with the number of tumor cells present. Furthermore, the direct addition of viable ascites EL4 cells to response cultures or assays had similar suppressive effects as late TBM spleen cells, i.e., inhibited cytotoxic T-lymphocytes, lymphokine activated killer cells, and splenic MO but had no effect on natural killer cells or peritoneal MO. The mechanism of suppression by ascites EL4 was not determined but it was mediated by viable cells only and not due to contaminating viruses or other microorganisms.

Correlation between in vivo induction of cytokine gene expression by flavone acetic acid and strict dose dependency and therapeutic efficacy against murine renal cancer.

The investigational chemotherapeutic drug flavone acetic acid (FAA) acts as an immunomodulator by augmenting natural killer activity in both humans and rodents after in vivo administration. The accumulated data derived from a series of experiments also demonstrates that FAA synergizes with interleukin 2 (IL-2) for the treatment of murine renal cancer. The immunomodulatory and immunotherapeutic effects of FAA are strictly dose dependent with doses of FAA greater than 150 mg/kg effectively synergizing with IL-2, and doses less than 150 mg/kg exhibiting very little therapeutic effect. The antitumor and immunomodulatory effects of FAA are more pronounced in vivo than in vitro. Collectively, these results suggested that cytokines induced by FAA may contribute to these effects, and that the induction of such cytokines may also be very dose dependent. Studies were therefore initiated to investigate whether the in vivo administration of FAA would alter the expression of cytokine mRNA in leukocytes. Splenic leukocytes or liver nonparenchymal cells from untreated and FAA-treated mice were used as a source of RNA for Northern blot analysis. Interferon alpha and interferon gamma mRNA in the spleen was upregulated within 1.5 h after FAA administration, with peak induction occurring by about 2 h. An upregulation of tumor necrosis factor alpha mRNA was detected in the spleen by 0.5-1 h after treatment with peak induction occurring by 1-1.5 h. Induction of tumor necrosis factor alpha mRNA was also detected in hepatic nonparenchymal cells. No up-regulation of splenic mRNA for tumor necrosis factor beta, IL-1 alpha or beta, or IL-2 was detected after FAA administration. IFN and TNF activities were detectable in the serum by bioassay immediately following the appearance of mRNA in FAA mice. The observed up-regulation by FAA of cytokine mRNA and the corresponding serum protein was strictly dose dependent with substantial induction of both mRNA and proteins occurring only at FAA doses greater than or equal to 150 mg/kg, a dose range also shown to be the minimum required for immunomodulatory and immunotherapeutic effects. In summary, these results demonstrate that FAA acts as a potent inducer of at least three cytokines in vivo, and suggest that the immunomodulatory and immunotherapeutic effects of FAA may be partially mediated by these induced cytokines.

Effect of recombinant human tumor necrosis factor on the induction of murine macrophage tumoricidal activity.

The ability of recombinant human tumor necrosis factor (rH-TNF) alone or in combination with lymphokines (LK) to induce the in vitro activation of murine macrophages was evaluated. The treatment of C57BL/6 mouse resident peritoneal exudate cells (PEC) with rH-TNF and LK was found to induce the activation of macrophages to a tumoricidal state against P815 mastocytoma cells. Neither rH-TNF nor LK alone induced macrophage cytotoxic activity. Furthermore, the macrophage activation seen was not due to small amounts of contaminating lipopolysaccharide. The TNF plus LK-mediated macrophage activation could be totally ablated by rabbit antiserum to murine gamma-interferon, thus suggesting a role for gamma-interferon in this system. Since adherent cells (greater than or equal to 95% macrophages) only marginally responded to stimulation with rH-TNF plus LK and the addition of nonadherent PEC caused a marked augmentation of rH-TNF plus LK-mediated macrophage activation, the involvement of nonadherent PEC was suggested. In addition, using antibodies and complement to deplete subsets of cells from the nonadherent PEC, the requirement for cells bearing Thy 1.2 and asialo GM1 surface markers was demonstrated. These results suggest that TNF may play an autocrine regulatory role in concert with lymphokines in macrophage-mediated host defense against malignant neoplasia.

Role of tumor necrosis factor in macrophage activation and tumoricidal activity.

Tumor necrosis factor (TNF)-sensitive (LM) and -insensitive (P815) target cell lines were used to examine the role of TNF in both the activation and lytic phases of macrophage-mediated lysis. LM cells were lysed spontaneously by thioglycolate-elicited macrophages in an 18-h assay (media or activating agents added with targets) or 36-h assay (macrophages cultured with media or activating agents for 18 h, washed, and targets added for a subsequent 18 h). In contrast, P815 cells were lysed only in the 36-h assay by macrophages exposed to appropriate activation signals. Using antibody to murine TNF, it was shown that lysis of LM cells but not P815 cells was TNF mediated. The addition of lipopolysaccharide (LPS) to the 18-h assay resulted in augmented LM killing. This was probably due to the fact that LPS stimulates macrophages to produce TNF. Conversely, when macrophages were pretreated with LPS for 18 h, washed, and assessed for lytic activity during the subsequent 18 h, lysis of LM cells was reduced relative to the endogenous level. Although macrophage lysis of P815 was not mediated by TNF, the addition of TNF to macrophage activation cultures facilitated LPS triggering of cytolytic activity against P815. Similarly, the addition of TNF to the activation cultures partially prevented the LPS-induced reduction in macrophage-mediated LM cell lysis. Taken together, these data suggest that TNF may act as an autocrine signal during macrophage activation, in addition to being directly lytic to a select number of sensitive target cell lines.

Adriamycin-induced modulation of host defenses in tumor-bearing mice.

Using the C57BL/6/EL4 tumor model, studies were carried out to demonstrate the feasibility of administering Adriamycin (ADM) in therapeutic doses and schedules such that the host antitumor defenses would not be suppressed and in some cases might be stimulated by treatment. ADM treatment caused prolongation of survival and, in general, either stimulated host cytolytic activities above untreated control levels or had no effect. These effects by ADM were observed with the ADM-sensitive parent EL4 line as well as with an ADM-resistant subline, indicating that the effects did not result entirely from direct antitumor activity. The cytolytic activities examined were those of cytolytic T-lymphocytes, lymphokine-activated killer cells, and splenic and peritoneal macrophages. All activities were assessed against the syngeneic EL4 target line. The information obtained in this investigation provides a rational basis for the future development of curative protocols with ADM plus biological response modifiers, which would depend on a functional immune system for optimum efficacy and would also exploit synergistic immunomodulating effects of the agents used in combination.

Reconstitution of telomerase activity combined with HPV-E7 expression allow human preadipocytes to preserve their differentiation capacity after immortalization.

Overexpression of SV40 T-antigen (SV40 T-Ag) has been widely used to overcome replicative senescence of human primary cells and to promote cell immortalization. However, in the case of certain cell types, such as preadipocytes, the differentiation process of immortalized cells is blocked by SV40 T-Ag expression. In this study, human telomerase reverse transcriptase (hTERT) and papillomavirus E7 oncoprotein (HPV-E7) genes were coexpressed in human preadipocytes to test whether this combination could maintain cell differentiation capacity after immortalization. We demonstrated that the HPV-E7/hTERT expressing preadipocytes displayed an indefinite life span. Interestingly, immortalized cells were diploid and presented no chromosomic alterations. These immortalized cells were able to accumulate and hydrolyze intracellular triglycerides and to express adipocyte markers. These data demonstrate, for the first time, that coexpression of hTERT and HPV-E7 in human preadipocytes allows cells not only to display an indefinite life span but also to retain their capacity to differentiate.

Differential inhibition of platelet aggregation induced by adenosine diphosphate or a thrombin receptor-activating peptide in patients treated with bolus chimeric 7E3 Fab: implications for inhibition of the internal pool of GPIIb/IIIa receptors.

OBJECTIVES: This study sought to describe in detail the pharmacokinetics and pharmacodynamics of chimeric monoclonal 7E3 Fab (c7E3 Fab) and to compare platelet responses to adenosine diphosphate (ADP) and the 11-amino acid thrombin receptor-activating peptide (TRAP [SFLLRNPNDKY-NH2]) in patients undergoing elective coronary angioplasty. BACKGROUND: Inhibition of platelet aggregation with monoclonal antibody c7E3 Fab directed against glycoprotein (GP) IIb/IIIa has been shown to reduce ischemic complications after angioplasty and is being considered for treatment of other acute ischemic syndromes. METHODS: Patients undergoing elective coronary angioplasty received aspirin (325 mg orally), heparin (12,000 U intravenously) and a bolus of c7E3 Fab (0.25 mg/kg body weight). Surface GPIIb/IIIa receptor blockade and aggregation in response to 20 mumol/liter ADP, 5 micrograms/ml collagen and 7.5 and 15 mumol/liter TRAP were assessed. RESULTS: Surface GPIIb/IIIa receptor blockade by c7E3 Fab was 80% 2 h after injection and decreased to 50% at 24 h. Platelet aggregation in response to 20 mumol/liter ADP was inhibited by 73% at 2 h, and this inhibition decreased to 27% at 24 h. Platelet aggregation in response to 7.5 mumol/liter TRAP was inhibited by 53% at 2 h and 30% at 24 h. In contrast, aggregation in response to 15 mumol/liter TRAP was inhibited only 37% at 2 h and 10% at 24 h (p < 0.001 and p = 0.006, respectively vs. 20 mumol/liter ADP). Addition of exogenous c7E3 Fab to platelet-rich plasma led to more complete inhibition of 7.5 mumol/liter TRAP-induced aggregation. CONCLUSIONS: After c7E3 Fab treatment, inhibition of platelet aggregation depends on the agonist and can be overcome by increased thrombin activity but is restored if additional c7E3 Fab is added to block additional GPIIb/IIIa receptors. This phenomenon may be related to an internal pool of GPIIb/IIIa receptors joining the surface membrane and has implications concerning the duration of therapy with c7E3 Fab for patients with unstable angina or acute myocardial infarction.