Orthogonal control of expression mean and variance by epigenetic features at different genomic loci

While gene expression noise has been shown to drive dramatic phenotypic variations, the molecular basis for this variability in mammalian systems is not well understood. Gene expression has been shown to be regulated by promoter architecture and the associated chromatin environment. However, the exact contribution of these two factors in regulating expression noise has not been explored. Using a dual-reporter lentiviral model system, we deconvolved the influence of the promoter sequence to systematically study the contribution of the chromatin environment at different genomic locations in regulating expression noise. By integrating a large-scale analysis to quantify mRNA levels by smFISH and protein levels by flow cytometry in single cells, we found that mean expression and noise are uncorrelated across genomic locations. Furthermore, we showed that this independence could be explained by the orthogonal control of mean expression by the transcript burst size and noise by the burst frequency. Finally, we showed that genomic locations displaying higher expression noise are associated with more repressed chromatin, thereby indicating the contribution of the chromatin environment in regulating expression noise.

A concept for the control of kidney production of erythropoietin involving prostaglandins and cyclic nucleotides

Our hypothesis is that PGs released within the kidney play a role in the modulation of kidney production of Ep. PGs release probably at medullary and/or cortical sites following erythropoietic stimuli such as hypoxic hypoxia, anemic hypoxia, and ischemic hypoxia induced by renal artery constriction increase kidney production of Ep. PGs which are released probably activate a renal cortical adenylate cyclase thereby enhancing the production of intracellular cAMP. This initiates the cascade of events resulting in the production and/or secretion of Ep by the kidney. The endoperoxide analogs and PGE2 have been found to produce a dose-related and Ep-dependent increase in radioiron incorporation into newly formed red blood cells of exhypoxic polycythemic mice. Indomethacin, a potent PG cyclo-oxygenase inhibitior, attenuates Ep production and the appearance of PGE in the renal venous effluent of animals exposed to hypoxic hypoxia and renal artery constriction. Arachidonic acid (C20:4) and PGE2 infusion into the posthypoxic isolated perfused dog kidney produced a significant elevation in Ep titers in the perfusate. The increase in Ep production caused by arachidonate is blocked by indomethacin. It has been previously reported that PGs of the E series stimulate cAMP formation in several tissues. We have found that not only are renal cortical cAMP levels significantly elevated in rats following exposure to hypobaric hypoxia but that dibutyryl cAMP administration produces an increase in hematocrit and circulating red cell mass in normal mice. Our data thus far strongly support the hypothesis that the renal PGs and the cyclic nucleotides are intimately involved in the pharmacologic and/or pathophysiologic control of Ep production. Further work is necessary to determine whether the PGs and cyclic nucleotides are involved in the day-to-day control of Ep production by the mammalian kidney.

Study to determine the durability of glycaemic control with early treatment with a vildagliptin-metformin combination regimen vs. standard-of-care metformin monotherapy-the VERIFY trial: a randomized double-blind trial

AIMS

Durability of good glycaemic control (HbA1c ) is of importance as it can be the foundation for delaying diabetic complications. It has been hypothesized that early initiation of treatment with the combination of oral anti-diabetes agents with complementary mechanisms of action can increase the durability of glycaemic control compared with metformin monotherapy followed by a stepwise addition of oral agents. Dipeptidyl peptidase-4 inhibitors are good candidates for early use as they are efficacious in combination with metformin, show weight neutrality and a low risk of hypoglycaemia. We aimed to test the hypothesis that early combined treatment of metformin and vildagliptin slows β-cell deterioration as measured by HbA1c .

METHODS

Approximately 2000 people with Type 2 diabetes mellitus who were drug-naive or who were treated with metformin for less than 1 month, and who have HbA1c of 48-58 mmol/mol (6.5-7.5%), will be randomized in a 1:1 ratio in VERIFY, a 5-year multinational, double-blind, parallel-group study designed to compare early initiation of a vildagliptin-metformin combination with standard-of-care initiation of metformin monotherapy, followed by the stepwise addition of vildagliptin when glycaemia deteriorates. Further deterioration will be treated with insulin. The primary analysis for treatment failure will be from a Cox proportional hazard regression model and the durability of glycaemic control will be evaluated by assessing treatment failure rate and the rate of loss in glycaemic control over time as co-primary endpoints.

SUMMARY

VERIFY is the first study to investigate the long-term clinical benefits of early combination treatment vs. the standard-of-care metformin monotherapy with a second agent added by threshold criteria.

Glucagon dynamics during hypoglycaemia and food-re-challenge following treatment with vildagliptin in insulin-treated patients with type 2 diabetes

AIMS

To determine the effects of dipeptidyl peptidase-4 (DPP-4) inhibition on glucagon dynamics in patients with insulin-treated type 2 diabetes (T2D).

METHODS

The study was a single-centre, double-blind, randomized, placebo controlled crossover study in patients with T2D, mean age 59 ± 6 (s.d.) years and mean haemoglobin A1c 7.7 ± 0.8%, treated with exogenous insulin with or without oral antihyperglycaemic agents. Patients received vildagliptin (50 mg BID) or placebo as add-on to insulin for 4 weeks in random order with a 4-week washout in-between. On day 28 of the respective treatment, patients were served a standard meal (500 kcal) followed by a hyperinsulinaemic hypoglycaemic clamp (target 2.5 mmol/l) and a subsequent food re-challenge (700 kcal). The completers population (n = 29) was analysed.

RESULTS

Glucose levels were lower with vildagliptin than with placebo during the meal [areas under the curve (AUC) 1.23 ± 0.07 vs. 1.46 ± 0.05 mol/l min, P < 0.001] and similar between the groups during the clamp. During the meal, glucagon levels were lower with vildagliptin (AUC 1.98 ± 0.15 vs. 2.15 ± 0.17 nmol/l min, P = 0.016). In contrast, the glucagon counter-regulation to the insulin-induced hypoglycaemia was sustained by vildagliptin (6.05 ± 1.20 pmol/l during vildagliptin vs.6.94 ± 1.09 pmol/l during placebo, NS). During the food re-challenge after hypoglycaemia, glucagon levels were, again, significantly lower after vildagliptin (AUC 1.30 ± 0.11 vs. 1.52 ± 0.12 nmol/l min, P < 0.039). Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) levels were significantly elevated by vildagliptin compared to placebo during meal, hypoglycaemia and food re-challenge.

CONCLUSIONS

Vildagliptin action to block GLP-1 and GIP inactivation by DPP-4 improves glucagon dynamics during hypoglycaemia, hyperglycaemia and food re-challenge.

Enhanced beta cell function and anti-inflammatory effect after chronic treatment with the dipeptidyl peptidase-4 inhibitor vildagliptin in an advanced-aged diet-induced obesity mouse model

AIMS/HYPOTHESIS

Studies have shown that dipeptidyl peptidase-4 (DPP4) inhibitors stimulate insulin secretion and increase beta cell mass in rodents. However, in these models hyperglycaemia has been induced early on in life and the treatment periods have been short. To explore the long-term effects of DPP4 inhibition on insulin secretion and beta cell mass, we have generated a high-fat diet (HFD)-induced-obesity model in mice of advanced age (10 months old).

METHODS

After 1 month of HFD alone, the mice were given the DPP4 inhibitor vildagliptin for a further 11 months. At multiple time points throughout the study, OGTTs were performed and beta cell area and long-term survival were evaluated.

RESULTS

Beta cell function and glucose tolerance were significantly improved by vildagliptin with both diets. In contrast, in spite of the long treatment period, beta cell area was not significantly different between vildagliptin-treated mice and controls. Mice of advanced age chronically fed an HFD displayed clear and extensive pancreatic inflammation and peri-insulitis, mainly formed by CD3-positive T cells, which were completely prevented by vildagliptin treatment. Chronic vildagliptin treatment also improved survival rates for HFD-fed mice.

CONCLUSIONS/INTERPRETATION

In a unique advanced-aged HFD-induced-obesity mouse model, insulin secretion was improved and the extensive peri-insulitis prevented by chronic DPP4 inhibition. The improved survival rates for obese mice chronically treated with vildagliptin suggest that chronic DPP4 inhibition potentially results in additional quality-adjusted life-years for individuals with type 2 diabetes, which is the primary goal of any diabetes therapy.

Engineering customized TALE nucleases (TALENs) and TALE transcription factors by fast ligation-based automatable solid-phase high-throughput (FLASH) assembly

Customized DNA-binding domains made using transcription activator-like effector (TALE) repeats are rapidly growing in importance as widely applicable research tools. TALE nucleases (TALENs), composed of an engineered array of TALE repeats fused to the FokI nuclease domain, have been used successfully for directed genome editing in various organisms and cell types. TALE transcription factors (TALE-TFs), consisting of engineered TALE repeat arrays linked to a transcriptional regulatory domain, have been used to up- or downregulate expression of endogenous genes in human cells and plants. This unit describes a detailed protocol for the recently described fast ligation-based automatable solid-phase high-throughput (FLASH) assembly method. FLASH enables automated high-throughput construction of engineered TALE repeats using an automated liquid handling robot or manually using a multichannel pipet. Using the automated approach, a single researcher can construct up to 96 DNA fragments encoding TALE repeat arrays of various lengths in a single day, and then clone these to construct sequence-verified TALEN or TALE-TF expression plasmids in a week or less. Plasmids required for FLASH are available by request from the Joung lab (http://eGenome.org). This unit also describes improvements to the Zinc Finger and TALE Targeter (ZiFiT Targeter) web server (http://ZiFiT.partners.org) that facilitate the design and construction of FLASH TALE repeat arrays in high throughput.

Salmonella Oranienburg isolated from horses, wild turkeys and an edible home garden fertilized with raw horse manure

In July 2010, a horse from a rural farm (Farm A) in coastal Northern California was diagnosed with Salmonella Oranienburg infection following referral to a veterinary hospital for colic surgery. Environmental sampling to identify potential sources and persistence of Salmonella on the farm was conducted from August 2010 to March 2011. Salmonella was cultured using standard enrichment and selective plating. Pure colonies were confirmed by biochemical analysis, serotyped and compared by pulsed-field gel electrophoresis (PFGE) analysis. A total of 204 clinical and environmental samples at Farm A were analysed, and Salmonella spp. was isolated from six of eight (75%) horses, an asymptomatic pet dog, two of seven (28.6%) water samples from horse troughs, nine of 20 (45%) manure storage pile composites, 16 of 71 (22.5%) wild turkey faeces and four of 39 (10.3%) soil samples from the family's edible home garden. Well water and garden vegetable samples and horse faecal samples from a neighbouring ranch were negative. S. Oranienburg with a PFGE pattern indistinguishable from the horse clinical strain was found in all positive sample types on Farm A. The investigation illustrates the potential for widespread dissemination of Salmonella in a farm environment following equine infections. We speculate that a recent surge in the wild turkey population on the property could have introduced S. Oranienburg into the herd, although we cannot rule out the possibility wild turkeys were exposed on the farm or to other potential sources of Salmonella. Findings from the investigation indicated that raw horse manure applied as fertilizer was the most likely source of garden soil contamination. Viable S. Oranienburg persisted in garden soil for an estimated 210 days, which exceeds the 120-day standard between application and harvest currently required by the National Organic Program. The study underscores the need to educate the public about potential food safety hazards associated with using raw animal manure to fertilize edible home gardens.

Studies in rodents with the dipeptidyl peptidase-4 inhibitor vildagliptin to evaluate possible drug-induced pancreatic histological changes that are predictive of pancreatitis and cancer development in man

AIM

The present report summarizes rodent studies with vildagliptin, relevant to predicting pancreatitis or pancreatic cancer in man.

METHODS

As part of the regulatory development program for vildagliptin, a rodent toxicity program included two 104-week rodent (mouse and rat) carcinogenicity studies that were conducted according to guidelines assigned in Food and Drug Administration's Draft Guidance for Industry.

RESULTS

Vildagliptin exposure in animals was evaluated for its effects on endocrine and exocrine pancreas. Two-year carcinogenicity studies were conducted in rats at oral doses up to 900 mg/kg (approximately 200 times the human exposure at the maximum recommended dose) and in mice at oral doses up to 1000 mg/kg (up to 240 times the human exposure at the maximum recommended dose). The results from these studies show the expected preservation and growth of the endocrine β-cells with no significant findings in the exocrine acinar pancreas. There was no evidence of inflammatory infiltrates characteristic of pancreatitis, no palpable mass detection based on gross examination or any microscopic findings indicative of pancreatic islet cell (endocrine), acinar cell (exocrine) or ductal (exocrine) neoplasia in rat or mouse.

CONCLUSIONS

Evaluation of vildagliptin in 2-year preclinical carcinogenicity studies in both rats and mice indicates that while vildagliptin results in pharmacological benefits to the endocrine pancreas, this was not associated with any evidence of pancreatitis, pancreatic islet cell, acinar cell or ductal neoplasia. These data predict no increased risk of pancreatic cancer in man.

Chromatin accessibility at the HIV LTR promoter sets a threshold for NF-κB mediated viral gene expression

Higher order chromatin structure in eukaryotes can lead to differential gene expression in response to the same transcription factor; however, how transcription factor inputs integrate with quantitative features of the chromatin environment to regulate gene expression is not clear. In vitro models of HIV gene regulation, in which repressive mechanisms acting locally at an integration site keep proviruses transcriptionally silent until appropriately stimulated, provide a powerful system to study gene expression regulation in different chromatin environments. Here we quantified HIV expression as a function of activating transcription factor nuclear factor-κB RelA/p65 (RelA) levels and chromatin features at a panel of viral integration sites. Variable RelA overexpression demonstrated that the viral genomic location sets a threshold RelA level necessary to induce gene expression. However, once the induction threshold is reached, gene expression increases similarly for all integration sites. Furthermore, we found that higher induction thresholds are associated with repressive histone marks and a decreased sensitivity to nuclease digestion at the LTR promoter. Increasing chromatin accessibility via inhibition of histone deacetylation or DNA methylation lowered the induction threshold, demonstrating that chromatin accessibility sets the level of RelA required to activate gene expression. Finally, a functional relationship between gene expression, RelA level, and chromatin accessibility accurately predicted synergistic HIV activation in response to combinatorial pharmacological perturbations. Different genomic environments thus set a threshold for transcription factor activation of a key viral promoter, which may point toward biological principles that underlie selective gene expression and inform strategies for combinatorial therapies to combat latent HIV.

Mechanisms of action of the dipeptidyl peptidase-4 inhibitor vildagliptin in humans

Inhibition of dipeptidyl peptidase-4 (DPP-4) by vildagliptin prevents degradation of glucagon-like peptide-1 (GLP-1) and reduces glycaemia in patients with type 2 diabetes mellitus, with low risk for hypoglycaemia and no weight gain. Vildagliptin binds covalently to the catalytic site of DPP-4, eliciting prolonged enzyme inhibition. This raises intact GLP-1 levels, both after meal ingestion and in the fasting state. Vildagliptin has been shown to stimulate insulin secretion and inhibit glucagon secretion in a glucose-dependent manner. At hypoglycaemic levels, the counterregulatory glucagon response is enhanced relative to baseline by vildagliptin. Vildagliptin also inhibits hepatic glucose production, mainly through changes in islet hormone secretion, and improves insulin sensitivity, as determined with a variety of methods. These effects underlie the improved glycaemia with low risk for hypoglycaemia. Vildagliptin also suppresses postprandial triglyceride (TG)-rich lipoprotein levels after ingestion of a fat-rich meal and reduces fasting lipolysis, suggesting inhibition of fat absorption and reduced TG stores in non-fat tissues. The large body of knowledge on vildagliptin regarding enzyme binding, incretin and islet hormone secretion and glucose and lipid metabolism is summarized, with discussion of the integrated mechanisms and comparison with other DPP-4 inhibitors and GLP-1 receptor activators, where appropriate.

Beta cell function following 1 year vildagliptin or placebo treatment and after 12 week washout in drug-naive patients with type 2 diabetes and mild hyperglycaemia: a randomised controlled trial

AIMS/HYPOTHESIS

Traditional blood glucose lowering agents do not prevent the progressive loss of beta cell function in patients with type 2 diabetes. The dipeptidylpeptidase (DPP)-4 inhibitor vildagliptin improves beta cell function both acutely and chronically (up to 2 years). Whether this effect persists after cessation of treatment remains unknown. Here, we assessed the insulin secretory capacity in drug-naive patients with type 2 diabetes after a 52 week treatment period with vildagliptin or placebo, and again after a 12 week washout period.

METHODS

This study was conducted at a single university medical centre, and was a double-blind, randomised clinical trial in 59 drug-naive patients with type 2 diabetes and mild hyperglycaemia to either vildagliptin 100 mg (n = 29) or placebo (n = 30). Randomisation was performed by a validated 1:1 system. Neither patient, nor caregiver, was informed about the assigned treatment. Inclusion criteria were drug-naive patients ≥30 years, with HbA(1c) ≤7.5% and BMI of 22-45 kg/m(2). The mildly hyperglycaemic patient population was chosen to minimise glucose toxicity as a confounding variable. Beta-cell function was measured during an arginine-stimulated hyperglycaemic clamp at week 0, week 52 and after a 12 week washout period. All patients with at least one post-randomisation measure were analysed (intent-to-treat).

RESULTS

Fifty-two week vildagliptin 100 mg (n = 26) treatment increased the primary efficacy variable, combined hyperglycaemia and arginine-stimulated C-peptide secretion (AIR(arg)), by 5.0 ± 1.8 nmol/l × min, while it decreased by 0.8 ± 1.8 nmol/l × min with placebo (n = 25) (between-group difference p = 0.030). No significant between-group difference in AIR(arg) was seen after the 12 week washout period. The between-group difference adjusted mean 52 week changes from baseline was -0.19 ± 0.11, p = 0.098 and -0.22 ± 0.23%, p = 0.343 for HbA(1c) and fasting plasma glucose, respectively. There were no suspected drug treatment-related serious adverse events.

CONCLUSIONS/INTERPRETATION

One year treatment with vildagliptin significantly increased beta cell secretory capacity. This effect was not maintained after the washout, indicating that this increased capacity was not a disease modifying effect on beta cell mass and/or function.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00260156.

Comparison of diagnostic methods to detect piroplasms in asymptomatic cattle

This study was carried out to compare different diagnostic techniques to reveal the presence of piroplasms in asymptomatic cattle kept at pasture. Nineteen blood samples were collected from animals of two different areas of Emilia Romagna Region of Italy and processed for microscopic observation, PCR, serological test (IFAT) for Babesia bovis and Babesia bigemina antibodies and in vitro cultivation. The cultures were performed on both bovine and ovine erythrocytes. Seventeen blood smears (89%) were positive for piroplasms, while PCR was positive on 18 samples (95%). DNA sequencing of 18S rRNA identified the piroplasms as Theileria spp. In vitro cultures were successful for 6 samples (32%) cultured on bovine blood and subsequent identified these as Babesia major by PCR. On IFAT analyses of 16 samples, 36.8% resulted positive for B. bovis and 31.6% positive for B. bigemina. These results show, in the same animals, the co-infection with Babesia spp. and Theileria spp.; the detection of B. major was possible only using the in vitro cultures.

Clinical evidence and mechanistic basis for vildagliptin's action when added to metformin

Several new oral antidiabetic agents, known as 'gliptins' or 'enzyme dipeptidyl peptidase-IV (DPP-4) inhibitors', have been developed for the treatment of type 2 diabetes and a key clinical use of the gliptins is in combination with metformin. There are important differences in the kinetics of the interaction of different gliptins with the catalytic site of DPP-4, which may lead to varying pharmacokinetics, pharmacodynamics and dosing regimens. Therefore, individual gliptins need to be characterized and here we discuss the extensively studied DPP-4 inhibitor vildagliptin, which has binding characteristics that ensure inhibition of the enzyme beyond the presence of detectable drug levels in plasma. As vildagliptin has been used most often at doses of 50 mg once or twice daily, in combination with metformin, this review focuses on these dose regimens. All clinical trials employing vildagliptin (50 mg once or twice daily) as an add-on therapy to metformin (identified by MEDLINE search using keywords vildagliptin and metformin or known by authors to be in press) are reviewed, as is current knowledge of the mechanism of action of vildagliptin. Vildagliptin added to a stable dose of metformin elicits a dose-related decrease in both HbA1c and fasting plasma glucose. The additional efficacy seen with 50 mg twice daily [ΔHbA1c ∼- 1.1% (-12.1 mmol/mol)] relative to 50 mg once daily [ΔHbA1c ∼- 0.7% (-7.7 mmol/mol)] is attributable to an overnight effect of the evening dose of vildagliptin, with prolonged DPP-4 inhibition and elevated fasting levels of the intact and insulinotropic form of glucagon-like peptide-1 (GLP-1). Vildagliptin's therapeutic actions are primarily mediated by GLP-1 and metformin enhances vildagliptin's effect to raise plasma levels of intact GLP-1. Vildagliptin is weight-neutral and has a very low hypoglycaemic potential, explained by its remarkable ability to enhance both α-cell and β-cell sensitivity to glucose. Therefore, vildagliptin offers a clinically important outcome when added to metformin with a twice daily dose regimen, taking advantage of its tight binding and slow dissociation characteristics that lead to a sustained overnight effect.

Clinical experience with vildagliptin in the management of type 2 diabetes in a patient population ≥75 years: a pooled analysis from a database of clinical trials

AIM

To report the experience with vildagliptin in a patient population with type 2 diabetes mellitus (T2DM) ≥75 years.

METHODS

Efficacy data from seven monotherapy and three add-on therapy to metformin studies, respectively, of ≥24 weeks duration were pooled; effects of 24 weeks of treatment with vildagliptin (50 mg bid) in patients ≥75 years were assessed in these two pooled datasets. Safety data were pooled from 38 studies of ≥12 to ≥104 weeks duration; adverse events (AEs) profiles of vildagliptin (50 mg bid) were evaluated relative to a pool of comparators; 301 patients ≥75 years were analysed. Data in patients <75 years are provided as a reference.

RESULTS

Mean age of the elderly population was 77 years. Changes in haemoglobin A1c (HbA1c) with vildagliptin in the patient group ≥75 years were -0.9% from a baseline of 8.3% in monotherapy (p < 0.0001) and -1.1% from a baseline of 8.5% in add-on therapy to metformin (p = 0.0004), and these reductions were similar to those seen in the younger patients. The corresponding weight changes in the elderly patients were -0.9 kg (p = 0.0277) and -0.2 kg [not significant (NS)], respectively, and no confirmed hypoglycaemic events, including no severe events, were reported. AEs, drug-related AEs, serious adverse events (SAEs) and deaths were reported with a lower frequency in older patients receiving vildagliptin than comparators [133.9 vs. 200.6, 14.5 vs. 21.8, 8.8 vs. 16.5 and 0.0 vs. 1.7 events per 100 subject year exposure (SYE), respectively], and the incidence of discontinuations due to AEs was similar in the two groups (7.2 vs. 7.5 events per 100 SYE, respectively). The safety profile of vildagliptin was overall similar in younger and older patients.

CONCLUSIONS

Vildagliptin was effective and well-tolerated in type 2 diabetic patients ≥75 years (mean age 77 years).

Predicting success of oligomerized pool engineering (OPEN) for zinc finger target site sequences

BACKGROUND

Precise and efficient methods for gene targeting are critical for detailed functional analysis of genomes and regulatory networks and for potentially improving the efficacy and safety of gene therapies. Oligomerized Pool ENgineering (OPEN) is a recently developed method for engineering C2H2 zinc finger proteins (ZFPs) designed to bind specific DNA sequences with high affinity and specificity in vivo. Because generation of ZFPs using OPEN requires considerable effort, a computational method for identifying the sites in any given gene that are most likely to be successfully targeted by this method is desirable.

RESULTS

Analysis of the base composition of experimentally validated ZFP target sites identified important constraints on the DNA sequence space that can be effectively targeted using OPEN. Using alternate encodings to represent ZFP target sites, we implemented Naïve Bayes and Support Vector Machine classifiers capable of distinguishing "active" targets, i.e., ZFP binding sites that can be targeted with a high rate of success, from those that are "inactive" or poor targets for ZFPs generated using current OPEN technologies. When evaluated using leave-one-out cross-validation on a dataset of 135 experimentally validated ZFP target sites, the best Naïve Bayes classifier, designated ZiFOpT, achieved overall accuracy of 87% and specificity+ of 90%, with an ROC AUC of 0.89. When challenged with a completely independent test set of 140 newly validated ZFP target sites, ZiFOpT performance was comparable in terms of overall accuracy (88%) and specificity+ (92%), but with reduced ROC AUC (0.77). Users can rank potentially active ZFP target sites using a confidence score derived from the posterior probability returned by ZiFOpT.

CONCLUSION

ZiFOpT, a machine learning classifier trained to identify DNA sequences amenable for targeting by OPEN-generated zinc finger arrays, can guide users to target sites that are most likely to function successfully in vivo, substantially reducing the experimental effort required. ZiFOpT is freely available and incorporated in the Zinc Finger Targeter web server (http://bindr.gdcb.iastate.edu/ZiFiT).

HIV promoter integration site primarily modulates transcriptional burst size rather than frequency

Mammalian gene expression patterns, and their variability across populations of cells, are regulated by factors specific to each gene in concert with its surrounding cellular and genomic environment. Lentiviruses such as HIV integrate their genomes into semi-random genomic locations in the cells they infect, and the resulting viral gene expression provides a natural system to dissect the contributions of genomic environment to transcriptional regulation. Previously, we showed that expression heterogeneity and its modulation by specific host factors at HIV integration sites are key determinants of infected-cell fate and a possible source of latent infections. Here, we assess the integration context dependence of expression heterogeneity from diverse single integrations of a HIV-promoter/GFP-reporter cassette in Jurkat T-cells. Systematically fitting a stochastic model of gene expression to our data reveals an underlying transcriptional dynamic, by which multiple transcripts are produced during short, infrequent bursts, that quantitatively accounts for the wide, highly skewed protein expression distributions observed in each of our clonal cell populations. Interestingly, we find that the size of transcriptional bursts is the primary systematic covariate over integration sites, varying from a few to tens of transcripts across integration sites, and correlating well with mean expression. In contrast, burst frequencies are scattered about a typical value of several per cell-division time and demonstrate little correlation with the clonal means. This pattern of modulation generates consistently noisy distributions over the sampled integration positions, with large expression variability relative to the mean maintained even for the most productive integrations, and could contribute to specifying heterogeneous, integration-site-dependent viral production patterns in HIV-infected cells. Genomic environment thus emerges as a significant control parameter for gene expression variation that may contribute to structuring mammalian genomes, as well as be exploited for survival by integrating viruses.

Vildagliptin add-on to metformin produces similar efficacy and reduced hypoglycaemic risk compared with glimepiride, with no weight gain: results from a 2-year study

AIM

To show that vildagliptin added to metformin is non-inferior to glimepiride in reducing HbA1c levels from baseline over 2 years.

METHODS

A randomized, double-blind, active-comparator study of patients with type 2 diabetes mellitus inadequately controlled (HbA1c 6.5-8.5%) by metformin monotherapy. Patients received vildagliptin (50 mg twice daily) or glimepiride (up to 6 mg/day) added to metformin.

RESULTS

In all, 3118 patients were randomized (vildagliptin, n = 1562; glimepiride, n = 1556). From similar baseline values (7.3%), after 2 years adjusted mean (s.e.) change in HbA1c was comparable between vildagliptin and glimepiride treatment: -0.1% (0.0%) and -0.1% (0.0%), respectively. The primary objective of non-inferiority was met. A similar proportion of patients reached HbA1c <7% (36.9 and 38.3%, respectively), but with vildagliptin more patients reached this target without hypoglycaemia (36.0% vs. 28.8%; p = 0.004). The initial response (IR) was sustained for a mean (s.d.) of 309 (244) days with vildagliptin versus 270 (223) days for glimepiride (p < 0.001) (IR = nadir HbA1c where change from baseline > or =0.5% or HbA1c < or =6.5% within the first six months of treatment. After IR was detected, sustained response = time between nadir and an increase of >0.3% above IR). Independent of disease duration, age was a predictor of effect sustainability. Fewer patients experienced hypoglycaemia with vildagliptin (2.3% vs. 18.2% with glimepiride) with a 14-fold difference in the number of hypoglycaemic events (59 vs. 838). Vildagliptin had a beneficial effect on body weight [mean (s.e.) change from baseline -0.3 (0.1) kg; between-group difference -1.5 kg; p < 0.001]. Overall, both treatments were well tolerated and displayed similar safety profiles.

CONCLUSIONS

Vildagliptin add-on has similar efficacy to glimepiride after 2 years' treatment, with markedly reduced hypoglycaemia risk and no weight gain.

An assessment of adverse effects of vildagliptin versus comparators on the liver, the pancreas, the immune system, the skin and in patients with impaired renal function from a large pooled database of Phase II and III clinical trials

AIM

To assess the safety of vildagliptin versus all comparators (ACs) with regard to organs, systems or tissues of particular interest in type 2 diabetes (T2DM) and areas of potential concern with dipeptidyl peptidase-IV (DPP-4) inhibitors.

METHODS

Data were pooled from 38 studies where vildagliptin was given for > or =12 to > 104 weeks in patients with T2DM. Absolute and exposure-adjusted incidence rates and Peto odds ratios (ORs) versus ACs with corresponding 95% confidence intervals (CI) were calculated.

RESULTS

There were > 7000 subject-years of exposure (SYE) to vildagliptin 50 mg bid and > 6500 SYE to ACs. For mild hepatic enzyme elevations with and without elevated bilirubin levels, the ORs for vildagliptin 50 mg bid were 1.24 (95% CI: [0.80, 1.93]) and 1.19 (95% CI: [0.29, 4.90]), respectively. The exposure-adjusted incidences of markedly elevated hepatic enzymes and for enzyme elevations with bilirubin > or = 2x ULN with vildagliptin 50 mg bid were < or = those in the ACs group. For hepatic and pancreatitis-related AEs, the ORs for vildagliptin 50 mg bid were 0.87 (95% CI: [0.64, 1.19]) and 0.70 (95% CI: [0.26, 1.88]), respectively, and for any AE in the infections and infestations SOC, this was 1.04 (95% CI: [0.96, 1.13]). The incidences of skin-related AEs were low and the risk with vildagliptin 50 mg bid was not significantly different from ACs [(OR = 1.10 (95% CI: [0.80, 1.51])].

CONCLUSIONS

The present meta-analyses indicate that vildagliptin was not associated with increased risk of hepatic events or hepatic enzyme elevations indicative of drug-induced liver injury, pancreatitis, infections or skin-related toxicity.

Assessing the cardio-cerebrovascular safety of vildagliptin: meta-analysis of adjudicated events from a large Phase III type 2 diabetes population

AIM

To assess the cardiovascular and cerebrovascular (CCV) safety of the dipeptidyl peptidase-IV inhibitor vildagliptin.

METHODS

Data were pooled from 25 Phase III studies of vildagliptin, used either as monotherapy or combination therapy, with durations of 12 weeks to > or = 2 years. The safety of vildagliptin [50 mg qd (N = 1393) or 50 mg bid (N = 6116)] was assessed relative to a pool of all comparators [both placebo and active comparators (N = 6061)]. CCV events were adjudicated in a prospective, blinded fashion by an independent CCV adjudication committee. Meta-analysis of confirmed CCV events was performed with Mantel-Haenszel risk ratios (RRs); categories included in the composite endpoint were acute coronary syndrome, transient ischaemic attack (with imaging evidence of infarction), stroke and CCV death. Subgroup analyses by age (< and > or = 65 years), gender and cardiovascular (CV) risk status [high CV risk status defined as a previous history of events in the Standard MedDRA Queries of ischaemic heart disease, cardiac failure, ischaemic cerebrovascular conditions and/or embolic/thrombotic events, arterial) were also carried out. In addition, unadjusted and exposure-adjusted incidences are presented for both the composite endpoint and its components.

RESULTS

Relative to all comparators, the RRs for the composite endpoint were < 1 for both vildagliptin 50 mg qd [RR = 0.88; 95% CI (0.37, 2.11)] and vildagliptin 50 mg bid [RR = 0.84; 95% CI (0.62, 1.14)]. The results were consistent across subgroups defined by age, gender and CV risk status, including the higher CV risk subgroups of elderly patients [RR for vildagliptin 50 mg bid vs. all comparators = 1.04; 95% CI (0.62, 1.73)], males [RR = 0.87; 95% CI (0.60, 1.24)] or patients with a high CV risk status [RR = 0.78; 95% CI (0.51, 1.19)]. The exposure-adjusted incidences of each component of the composite endpoint for vildagliptin 50 mg bid were also lower than or similar to those of all comparators.

CONCLUSIONS

In a large meta-analysis, vildagliptin was not associated with an increased risk of adjudicated CCV events relative to all comparators in the broad population of type 2 diabetes including patients at increased risk of CCV events.

Efficacy and safety comparison between the DPP-4 inhibitor vildagliptin and the sulfonylurea gliclazide after two years of monotherapy in drug-naïve patients with type 2 diabetes

This report is part of the overall evaluation of using vildagliptin in the treatment of type 2 diabetes. Here the results of a multi-center, double-blind, randomized, active-controlled study designed to compare the efficacy and safety of two years of monotherapy with vildagliptin 50 mg bid and gliclazide up to 320 mg/day in drug-naïve patients with type 2 diabetes are reported. A total of 546 patients were randomized and approximately 74% of patients completed the study in each group. HbA (1c) values were slightly higher in the gliclazide group (HbA (1c) of 8.7+/-0.1% vs. 8.5+/-0.1% in the vildagliptin group). The mean reduction in HbA (1c) from baseline to Week 104 was -0.5% in the vildagliptin group and -0.6% in the gliclazide group. The associated 95% confidence interval (CI) for the between-group difference (0.13%) in mean change was (-0.06%, 0.33%). Thus, noninferiority based on an upper limit of the CI of 0.3% was not met. In the vildagliptin group, weight increased by 0.8+/-0.2 kg compared to 1.6+/-0.2 kg in the gliclazide group (p<0.01). Mild hypoglycemia was recorded in 0.7% of patients in the vildagliptin group and in 1.7% in the gliclazide group. Both drugs were well tolerated. In summary, vildagliptin monotherapy resulted in improved glycemic control in drug-naïve patients with type 2 diabetes. Although the hypothesis of noninferiority to gliclazide was not borne out statistically, the reductions in HbA (1c) were similar over a two year period and vildagliptin had significant benefits in terms of less weight gain and less hypoglycemia.

Lack of detectable equine herpesviruses 1 and 2 in paraffin-embedded specimens of equine sarcoidosis

BACKGROUND

Equine sarcoidosis is a rare, multisystemic, noncaseating, granulomatous and lymphoplasmacytic disease of unknown etiology. A recent report described a horse with granulomatous skin disease displaying histologic, electron microscopic, and polymerase chain reaction (PCR) findings consistent with equine herpesvirus 2 (EHV-2).

OBJECTIVE

To investigate the presence of EHV-2 and equine herpesvirus 1 (EHV-1) in 8 horses with sarcoidosis.

ANIMALS

Eight horses with sarcoidosis, reported previously.

METHODS

Retrospective study. PCR assays of the tissues were performed to detect DNA associated with EHV-1 and EHV-2. For both herpesviruses the target was their respective glycoprotein B gene. Positive controls consisted of DNA from viral cultures of culturettes from naturally occurring respiratory infections of EHV-1 and EHV-2.

RESULTS

The PCR analyses for both equine herpesviruses' DNA were negative in all 8 horses.

CONCLUSION

The failure to detect DNA from EHV-1 and EHV-2 in paraffin-embedded skin of these 8 horses does not discount EHV-1 or EHV-2 as causing some cases of ES, but lends support to the presumably multifactorial etiologic nature of the disease.

Rapid mutation of endogenous zebrafish genes using zinc finger nucleases made by Oligomerized Pool ENgineering (OPEN)

BACKGROUND

Customized zinc finger nucleases (ZFNs) form the basis of a broadly applicable tool for highly efficient genome modification. ZFNs are artificial restriction endonucleases consisting of a non-specific nuclease domain fused to a zinc finger array which can be engineered to recognize specific DNA sequences of interest. Recent proof-of-principle experiments have shown that targeted knockout mutations can be efficiently generated in endogenous zebrafish genes via non-homologous end-joining-mediated repair of ZFN-induced DNA double-stranded breaks. The Zinc Finger Consortium, a group of academic laboratories committed to the development of engineered zinc finger technology, recently described the first rapid, highly effective, and publicly available method for engineering zinc finger arrays. The Consortium has previously used this new method (known as OPEN for Oligomerized Pool ENgineering) to generate high quality ZFN pairs that function in human and plant cells.

METHODOLOGY/PRINCIPAL FINDINGS

Here we show that OPEN can also be used to generate ZFNs that function efficiently in zebrafish. Using OPEN, we successfully engineered ZFN pairs for five endogenous zebrafish genes: tfr2, dopamine transporter, telomerase, hif1aa, and gridlock. Each of these ZFN pairs induces targeted insertions and deletions with high efficiency at its endogenous gene target in somatic zebrafish cells. In addition, these mutations are transmitted through the germline with sufficiently high frequency such that only a small number of fish need to be screened to identify founders. Finally, in silico analysis demonstrates that one or more potential OPEN ZFN sites can be found within the first three coding exons of more than 25,000 different endogenous zebrafish gene transcripts.

CONCLUSIONS AND SIGNIFICANCE

In summary, our study nearly triples the total number of endogenous zebrafish genes successfully modified using ZFNs (from three to eight) and suggests that OPEN provides a reliable method for introducing targeted mutations in nearly any zebrafish gene of interest.

Targeted mutagenesis in zebrafish using customized zinc-finger nucleases

Zebrafish mutants have traditionally been obtained by using random mutagenesis or retroviral insertions, methods that cannot be targeted to a specific gene and require laborious gene mapping and sequencing. Recently, we and others have shown that customized zinc-finger nucleases (ZFNs) can introduce targeted frame-shift mutations with high efficiency, thereby enabling directed creation of zebrafish gene mutations. Here we describe a detailed protocol for constructing ZFN expression vectors, for generating and introducing ZFN-encoding RNAs into zebrafish embryos and for identifying ZFN-generated mutations in targeted genomic sites. All of our vectors and methods are compatible with previously described Zinc-Finger Consortium reagents for constructing engineered zinc-finger arrays. Using these methods, zebrafish founders carrying targeted mutations can be identified within 4 months.

Adverse effects of dipeptidyl peptidases 8 and 9 inhibition in rodents revisited

AIM

To evaluate the association between inhibition of dipeptidyl peptidase (DPP)-8 and/or DPP-9 organ toxicities and mortality in rodents.

RESEARCH DESIGN AND METHODS

The relative selectivity of the DPP-4 inhibitor, vildagliptin, was determined by comparing its K(I) (concentration of compound yielding 50% inhibition of the enzyme) values for inhibition of recombinant human DPP-4, DPP-8 and DPP-9 assessed in vitro. In experiments performed in vivo, vildagliptin was administered by gavage for 13 weeks, at doses up to 1500 mg/kg/day in CD-1 mice and at doses up to 900 mg/kg/day in Wistar rats. Plasma concentrations of vildagliptin were assessed at week 12, and toxicities previously ascribed to inhibition of DPP-8 and/or DPP-9 were assessed at week 13.

RESULTS

The K(I) values for vildagliptin-induced inhibition of DPP-4, DPP-8 and DPP-9 were 3, 810 and 95 nM respectively. The mean plasma concentration 24 h after dose after 12-week daily dosing with 1500 mg/kg/day in mice was 2279 nM. The mean plasma drug level 24 h after dose after 12-week daily dosing with 900 mg/kg/day in rats was 5729 nM. These high doses maintained plasma drug levels well above the K(I) values for DPP-8 and DPP-9 throughout a 24-h period. At these high doses, the toxicities of a selective DPP-8/DPP-9 inhibitor that were reported previously (100% mortality in mice, alopecia, thrombocytopenia, reticulocytopenia, enlarged lymph nodes, splenomegaly and 20% mortality in rats) were not observed.

CONCLUSIONS

Inhibition of DPP-8 and DPP-9 per se does not lead to organ toxicities and mortality in rodents. Thus, a mechanism other than DPP-8/DPP-9 inhibition likely underlies the toxicity previously reported to be associated with a selective DPP-8/DPP-9 inhibitor.

Evidence that vildagliptin attenuates deterioration of glycaemic control during 2-year treatment of patients with type 2 diabetes and mild hyperglycaemia

AIM

To assess the 2-year efficacy and tolerability of vildagliptin (50 mg once daily) in patients with type 2 diabetes (T2DM) and mild hyperglycaemia.

METHODS

This was a multicentre, randomized, double-blind, placebo-controlled trial comprising a 52-week core study with a 4-week, active treatment-free washout followed by a 52-week extension study with another washout period conducted in 131 drug-naïve patients with T2DM and mild hyperglycaemia [glycosylated haemoglobin (HbA(1c)) 6.2-7.2%]. All patients received lifestyle counselling at each study visit. Efficacy and tolerability were assessed during visits at weeks 0 (core study baseline), 4, 8, 12, 16, 24, 32, 40 and 52 of active treatment; at week 56 (i.e. after the first washout period); at weeks 68, 80, 96 and 108 and at week 112 (i.e. after the second washout period). Standard meal tests were also performed at weeks 0, 24, 52, 56, 80, 108 and 112 to assess postprandial glycaemia and beta-cell function, which was quantified by glucose area under the curve (AUC(0-2) (h))/insulin secretory rate (ISR) AUC(0-2) (h) (ISR/G). Changes from baseline and between-treatment differences (placebo-adjusted changes from baseline during vildagliptin treatment) were analysed by ancova.

RESULTS

The placebo-adjusted change from week 0 in HbA(1c) was -0.3 +/- 0.1% after 1 year of vildagliptin treatment (p < 0.001) and -0.5 +/- 0.2% after 2 years (p = 0.008). The placebo-adjusted change from core study baseline in fasting plasma glucose, in glucose AUC(0-2) (h) and in the beta-cell function parameter, ISR/G, tended to be greater after 2 years than after 1 year of treatment with vildagliptin. Even after a 4-week washout, the placebo-adjusted change from week 0 to week 112 in ISR/G was 3.2 +/- 1.6 pmol/min/m(2)/mM (p = 0.058) and the placebo-adjusted difference in the change from week 0 to week 112 in HbA(1c) was -0.3 +/- 0.1% (p = 0.051). The incidences of adverse events (AEs), serious AEs and discontinuations because of AEs were similar in the two treatment groups, and hypoglycaemic episodes were reported by no patient receiving vildagliptin and by two patients receiving placebo.

CONCLUSIONS

In drug-naïve patients with mild hyperglycaemia, 2-year treatment with vildagliptin 50 mg once daily attenuated the progressive loss of glycaemic control seen in patients receiving only lifestyle counselling (and placebo). This appears to be because of a corresponding attenuation of the deterioration of beta-cell function as assessed by ISR/G.

Effects of vildagliptin on glucose control in patients with type 2 diabetes inadequately controlled with a sulphonylurea

AIM

To compare the efficacy and tolerability of vildagliptin vs. placebo in patients with type 2 diabetes mellitus (T2DM) who are inadequately controlled [haemoglobin A(1c) (HbA(1c)) 7.5 to 11%] with prior sulphonylurea (SU) monotherapy.

METHODS

This 24-week, multicentre, randomized, double-blind, placebo-controlled study assessed the effects of the dipeptidyl peptidase-4 inhibitor vildagliptin (50 mg given once or twice daily) vs. placebo added to glimepiride (4 mg once daily) in 515 patients with T2DM. Adjusted mean changes from baseline to end-point (AMDelta) in HbA(1c), fasting plasma glucose, fasting lipids and body weight were compared by analysis of covariance.

RESULTS

The between-group difference (vildagliptin - placebo) in AMDelta HbA(1c) was -0.6 +/- 0.1% in patients receiving vildagliptin 50 mg daily and -0.7 +/- 0.1% in those receiving 100 mg daily (p < 0.001 vs. placebo for both). Greater efficacy was seen in patients > or =65 years of age (-0.7 +/- 0.1% and -0.8 +/- 0.2% for 50 and 100 mg daily respectively) and in patients with baseline HbA(1c) > 9% (Delta = -1.0 +/- 0.2% and -0.9 +/- 0.2% for 50 and 100 mg daily respectively). Relative to placebo, patients receiving vildagliptin also had improvements in beta-cell function and postprandial glucose, with small changes in fasting lipids and body weight. The incidences of adverse events (AEs) (67.1, 66.3 and 64.2%) and serious AEs (2.9, 2.4 and 5.1%) were similar in patients receiving 50 mg vildagliptin, 100 mg vildagliptin or placebo respectively. The incidence of hypoglycaemic events was low but slightly higher in the group receiving vildagliptin 100 mg (3.6%) than in the group receiving vildagliptin 50 mg (1.2%) or placebo (0.6%).

CONCLUSIONS

In patients with T2DM inadequately controlled with prior SU monotherapy, addition of vildagliptin (50 or 100 mg daily) to glimepiride (4 mg once daily) improves glycaemic control and is well tolerated. Addition of vildagliptin 50 mg daily to SU monotherapy may be a particularly attractive therapy in elderly patients.

Robust improvements in fasting and prandial measures of beta-cell function with vildagliptin in drug-naïve patients: analysis of pooled vildagliptin monotherapy database

AIM

To assess the effects of 24-week treatment with vildagliptin on measures of beta-cell function in a broad spectrum of drug-naïve patients with type 2 diabetes (T2DM).

METHODS

Data from all double-blind, multicentre, randomized, placebo- or active-controlled trials conducted in drug-naïve patients with T2DM were pooled from all patients receiving monotherapy with vildagliptin (100 mg daily: 50 mg twice daily or 100 mg once daily, n = 1855) or placebo (n = 347). Fasting measures of beta-cell function [homeostasis model assessment of beta-cell function (HOMA-B) and proinsulin : insulin ratio] were assessed in the overall pooled monotherapy population. Standard meal tests were performed at baseline and week 24 in a subset of patients, and effects of vildagliptin (100 mg daily, n = 227) on dynamic (meal test-derived) measures of beta-cell function [insulin secretion rate relative to glucose (ISR/G) and insulinogenic indices] were assessed relative to baseline and vs. placebo (n = 29).

RESULTS

In the overall population, vildagliptin significantly increased HOMA-B both relative to baseline [adjusted mean change (AMDelta) = 10.3 +/- 1.5] and vs. placebo (between-treatment difference in AMDelta = 11.5 +/- 4.5, p = 0.01) and significantly decreased the proinsulin : insulin ratio relative to baseline (AMDelta = -0.05 +/- 0.01) and vs. placebo (between-treatment difference in AMDelta = -0.09 +/- 0.02, p < 0.001). Relative to baseline, vildagliptin monotherapy significantly increased all meal test-derived parameters, and ISR/G (between-treatment difference in AMDelta = 9.8 +/- 2.8 pmol/min/m(2)/mM, p < 0.001) and the insulinogenic index(0-peak glucose) (between-treatment difference in AMDelta = 0.24 +/- 0.05 pmol/mmol, p = 0.045) were significantly increased vs. placebo.

CONCLUSIONS

Vildagliptin monotherapy consistently produced robust improvements in both fasting and meal test-derived measures of beta-cell function across a broad spectrum of drug-naïve patients with T2DM. All Phase III trials described (NCT 00099905, NCT 00099866, NCT 00099918, NCT 00101673, NCT 00101803 and NCT 00120536) are registered with ClinicalTrials.gov.

Efficacy and tolerability of vildagliptin in drug-naïve patients with type 2 diabetes and mild hyperglycaemia*

AIM

This study was conducted to assess efficacy and tolerability of vildagliptin in drug-naïve patients with type 2 diabetes and mild hyperglycaemia.

METHODS

Multicentre, double-blind, randomized, placebo-controlled, parallel-group study of 52-week treatment with vildagliptin (50 mg q.d.) in 306 drug-naïve patients with type 2 diabetes (A1C = 6.2-7.5%). A1C, fasting plasma glucose (FPG) and measures of prandial glucose control and beta-cell function determined during standard meal tests were assessed.

RESULTS

Baseline A1C and FPG averaged 6.7% and 7.1 mmol/l, respectively, in patients randomized to vildagliptin (n = 156) and 6.8% and 7.2 mmol/l in those randomized to placebo (n = 150). A1C decreased modestly in vildagliptin-treated patients (Delta = -0.2 +/- 0.1%) and increased in patients receiving placebo (Delta = 0.1 +/- 0.1%). The between-group difference (vildagliptin - placebo) in adjusted mean change (AM Delta) in A1C was -0.3 +/- 0.1% (p < 0.001). FPG increased in patients receiving placebo (Delta = 0.5 +/- 0.1 mmol/l) and to a significantly lesser extent in vildagliptin-treated patients (between-group difference in AM Delta FPG = -0.4 +/- 0.2 mmol/l, p = 0.032). Relative to placebo, 2-h postprandial glucose (PPG) decreased (-0.9 +/- 0.4 mmol/l, p = 0.012), and insulin secretory rate (ISR) relative to glucose [ISR area under the curve (AUC)(0-2) (h)/glucose AUC(0-2) (h)] increased (+5.0 +/- 1.2 pmol/min/m(2)/mM, p < 0.001). Mean body weight decreased by 0.5 +/- 0.3 kg in vildagliptin-treated patients and by 0.2 +/- 0.3 kg in patients receiving placebo. The side-effect profile of vildagliptin was similar to that of placebo, and one hypoglycaemic episode occurred in one patient receiving placebo.

CONCLUSIONS

In drug-naïve patients with mild hyperglycaemia, relative to placebo, 52-week treatment with vildagliptin 50 mg q.d. significantly decreases A1C, FPG and PPG and improves beta-cell function without weight gain or hypoglycaemia.

The islet enhancer vildagliptin: mechanisms of improved glucose metabolism

Vildagliptin is a potent, selective and reversible inhibitor of dipeptidyl peptidase-4 (DPP-4), the enzyme responsible for rapid inactivation of the incretin hormones glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP). GLP-1 and GIP are important for the maintenance of normal glucose homeostasis as they enhance the sensitivity of insulin (beta-cell) and glucagon (alpha-cell) secretion to glucose. The delicate balance that is achieved by the incretin hormones is disturbed in type 2 diabetes mellitus (T2DM). Mechanistic studies of vildagliptin performed to characterise the effects of DPP-4 inhibition on pancreatic islet function and glucose metabolism have found that vildagliptin produces dose-dependent reductions in DPP-4; these result in persistent levels of active GLP-1 and GIP in the circulation leading to improved beta-cell sensitivity to glucose and glucose-dependent insulin secretion, and improved alpha-cell sensitivity to glucose and reduction in inappropriate glucagon secretion. These islet effects in turn lead to a reduction of the inappropriate endogenous glucose production and glucose utilisation during meals, resulting in improved glucose tolerance, and to a reduction of the inappropriate endogenous glucose production during the postabsorptive period that contributes to a reduced fasting hyperglycaemia. These islet effects are associated with improved insulin sensitivity and reduced meal-related hypertriglyceridaemia. In contrast, the GLP-1 effect of significantly delaying gastric emptying was not evident with vildagliptin treatment. The metabolic benefits of vildagliptin observed in T2DM are also evident in subjects with impaired glucose tolerance. Hence, vildagliptin improves glucose metabolism mainly by improving islet function.

Rapid "open-source" engineering of customized zinc-finger nucleases for highly efficient gene modification

Custom-made zinc-finger nucleases (ZFNs) can induce targeted genome modifications with high efficiency in cell types including Drosophila, C. elegans, plants, and humans. A bottleneck in the application of ZFN technology has been the generation of highly specific engineered zinc-finger arrays. Here we describe OPEN (Oligomerized Pool ENgineering), a rapid, publicly available strategy for constructing multifinger arrays, which we show is more effective than the previously published modular assembly method. We used OPEN to construct 37 highly active ZFN pairs which induced targeted alterations with high efficiencies (1%-50%) at 11 different target sites located within three endogenous human genes (VEGF-A, HoxB13, and CFTR), an endogenous plant gene (tobacco SuRA), and a chromosomally integrated EGFP reporter gene. In summary, OPEN provides an "open-source" method for rapidly engineering highly active zinc-finger arrays, thereby enabling broader practice, development, and application of ZFN technology for biological research and gene therapy.

Comparison of vildagliptin and acarbose monotherapy in patients with Type 2 diabetes: a 24-week, double-blind, randomized trial

AIMS

To compare the efficacy and tolerability of the dipeptidyl peptidase-4 inhibitor, vildagliptin, with the alpha glucosidase inhibitor, acarbose, in drug-naive patients with Type 2 diabetes.

METHODS

This multi-centre, randomized, double-blind, parallel-arm study compared the efficacy and tolerability of vildagliptin (100 mg daily, given as 50 mg twice daily, n = 441) and acarbose (up to 300 mg daily, given as three equally divided doses, n = 220) during 24-week treatment in drug-naive patients with Type 2 diabetes.

RESULTS

Monotherapy with vildagliptin or acarbose decreased glycated haemoglobin (HbA(1c)) (baseline approximately 8.6%) to a similar extent during 24-week treatment. The adjusted mean change from baseline to end-point (AMDelta) in HbA(1c) was -1.4 +/- 0.1% and -1.3 +/- 0.1% in patients receiving vildagliptin and acarbose, respectively, meeting the statistical criterion for non-inferiority (upper limit of 95% confidence interval for between-treatment difference < or = 0.4%). The decrease in fasting plasma glucose was similar with acarbose (-1.5 +/- 0.2 mmol/l) and vildagliptin (-1.2 +/- 0.1 mmol/l). Body weight did not change in vildagliptin-treated patients (-0.4 +/- 0.1 kg) but decreased in acarbose-treated patients (-1.7 +/- 0.2 kg, P < 0.001 vs. vildagliptin). The proportion of patients experiencing any adverse event (AE) was 35% vs. 51% in patients receiving vildagliptin or acarbose, respectively; gastrointestinal AEs were significantly more frequent with acarbose (25.5%) than vildagliptin (12.3%, P < 0.001). No hypoglycaemia was reported for either group.

CONCLUSIONS

Vildagliptin is effective and well tolerated in patients with Type 2 diabetes, demonstrating similar glycaemic reductions to acarbose, but with better tolerability.

Evidence that vildagliptin attenuates deterioration of glycaemic control during 2-year treatment of patients with type 2 diabetes and mild hyperglycaemia

AIM

To assess the 2-year efficacy and tolerability of vildagliptin (50 mg once daily) in patients with type 2 diabetes (T2DM) and mild hyperglycaemia.

METHODS

This was a multicentre, randomized, double-blind, placebo-controlled trial comprising a 52-week core study with a 4-week, active treatment-free washout followed by a 52-week extension study with another washout period conducted in 131 drug-naïve patients with T2DM and mild hyperglycaemia [glycosylated haemoglobin (HbA(1c)) 6.2-7.2%]. All patients received lifestyle counselling at each study visit. Efficacy and tolerability were assessed during visits at weeks 0 (core study baseline), 4, 8, 12, 16, 24, 32, 40 and 52 of active treatment; at week 56 (i.e. after the first washout period); at weeks 68, 80, 96 and 108 and at week 112 (i.e. after the second washout period). Standard meal tests were also performed at weeks 0, 24, 52, 56, 80, 108 and 112 to assess postprandial glycaemia and beta-cell function, which was quantified by glucose area under the curve (AUC(0-2) (h))/insulin secretory rate (ISR) AUC(0-2) (h) (ISR/G). Changes from baseline and between-treatment differences (placebo-adjusted changes from baseline during vildagliptin treatment) were analysed by ancova.

RESULTS

The placebo-adjusted change from week 0 in HbA(1c) was -0.3 +/- 0.1% after 1 year of vildagliptin treatment (p < 0.001) and -0.5 +/- 0.2% after 2 years (p = 0.008). The placebo-adjusted change from core study baseline in fasting plasma glucose, in glucose AUC(0-2) (h) and in the beta-cell function parameter, ISR/G, tended to be greater after 2 years than after 1 year of treatment with vildagliptin. Even after a 4-week washout, the placebo-adjusted change from week 0 to week 112 in ISR/G was 3.2 +/- 1.6 pmol/min/m(2)/mM (p = 0.058) and the placebo-adjusted difference in the change from week 0 to week 112 in HbA(1c) was -0.3 +/- 0.1% (p = 0.051). The incidences of adverse events (AEs), serious AEs and discontinuations because of AEs were similar in the two treatment groups, and hypoglycaemic episodes were reported by no patient receiving vildagliptin and by two patients receiving placebo.

CONCLUSIONS

In drug-naïve patients with mild hyperglycaemia, 2-year treatment with vildagliptin 50 mg once daily attenuated the progressive loss of glycaemic control seen in patients receiving only lifestyle counselling (and placebo). This appears to be because of a corresponding attenuation of the deterioration of beta-cell function as assessed by ISR/G.

Improved meal-related insulin processing contributes to the enhancement of B-cell function by the DPP-4 inhibitor vildagliptin in patients with type 2 diabetes

The aim of this study was to evaluate the contribution of insulin processing to the improved meal-related B-cell function previously shown with the DPP-4 inhibitor vildagliptin. Fifty-five patients with type 2 diabetes (56.5+/-1.5 years; BMI=29.6+/-0.5 kg/m(2); FPG=9.9+/-0.2 mmol/l; HbA1c=7.7+/-0.1 %) were studied: 29 patients were treated with vildagliptin and 26 patients with placebo, both added to an ongoing metformin regimen (1.5-3.0 g/day). A standardized breakfast was given at baseline and after 52 weeks of treatment, and proinsulin related to insulin secretion was measured with C-peptide in the fasting and postprandial (over 4 h post-meal) states to evaluate B-cell function. The between-treatment difference (vildagliptin-placebo) in mean change from baseline in fasting proinsulin to C-peptide ratio (fastP/C) was -0.007+/-0.009 (p=0.052). Following the standard breakfast, 52 weeks of treatment with vildagliptin significantly decreased the dynamic proinsulin to C-peptide ratio (dynP/C) relative to placebo by 0.010+/-0.008 (p=0.037). Importantly, when the P/C was expressed in relation to the glucose stimulus (i.e., the fasting glucose and glucose AUC(0-240 min), respectively), the P/C relative to glucose was significantly reduced with vildagliptin vs. placebo, both in the fasting state (p=0.023) and postprandially (p=0.004). In conclusion, a more efficient B-cell insulin processing provides further evidence that vildagliptin treatment ameliorates abnormal B-cell function in patients with type 2 diabetes.

Comparison between vildagliptin and metformin to sustain reductions in HbA(1c) over 1 year in drug-naïve patients with Type 2 diabetes

AIMS

To evaluate the ability of vildagliptin and metformin to sustain reductions in HbA(1c) over a 1-year treatment period in drug-naïve patients with Type 2 diabetes (Type 2 DM).

METHODS

Double-blind, randomized, multicentre, active-controlled, parallel-group study of 52-week treatment with vildagliptin (100 mg daily, n = 526) or metformin (titrated to 2000 mg daily, n = 254) in drug-naïve patients (baseline HbA(1c) = 7.5-11.0%). HbA(1c) was measured periodically over 1 year.

RESULTS

Vildagliptin and metformin each rapidly decreased HbA(1c) from an equal baseline of 8.7%. Most of the HbA(1c) reduction was attained by week 12, and the efficacy was sustained throughout 1-year treatment with both agents. At the study end, significant HbA(1c) reductions from baseline were seen with both vildagliptin (-1.0 +/- 0.1%, P < 0.001) and metformin (-1.4 +/- 0.1%, P < 0.001); however, statistical non-inferiority of 50 mg vildagliptin twice daily to 1000 mg metformin twice daily was not established. Body weight did not change during the 1-year treatment with vildagliptin (0.3 +/- 0.2 kg, P = 0.17) and decreased in metformin-treated patients (-1.9 +/- 0.3 kg, P < 0.001). The proportion of patients experiencing an adverse event was 70.1 vs. 75.4% in patients receiving vildagliptin and metformin, respectively. The proportion of patients experiencing a gastrointestinal adverse event was twofold higher in the metformin group, driven by a 3-4-fold greater incidence of diarrhoea, nausea and abdominal pain. The incidence of hypoglycaemia was similarly low in both groups (< 1%).

CONCLUSIONS

A clinically meaningful decrease in HbA(1c) that was sustained throughout a 1-year treatment in drug-naïve patients with Type 2 DM was seen with both metformin and vildagliptin monotherapy.

Vildagliptin in drug-naïve patients with type 2 diabetes: a 24-week, double-blind, randomized, placebo-controlled, multiple-dose study

This 24-week double-blind, randomized, multicenter, placebo-controlled, parallel-group study was performed in 632 drug-naïve patients with type 2 diabetes to assess efficacy and tolerability of vildagliptin (50 mg qd, 50 mg bid, or 100 mg qd). HbA1c decreased modestly in patients receiving placebo (Delta=-0.3+/-0.1%) and to a significantly greater extent in patients receiving vildagliptin 50 mg qd (Delta=-0.8+/-0 .1%), 50 mg bid (Delta=-0.8+/-0.1%), or 100 mg qd (Delta=-0.9+/-0.1%, p<0.01 for all groups VS. placebo) from an average baseline of 8.4%. In patients diagnosed >or=3 months before enrollment, HbA1c increased with placebo (Delta=+0.2+/-0.2%) and between-treatment differences (vildagliptin-placebo) were -0.8+/-0.2% (p<0.001), -0.7+/-0.2% (p=0.003), and -0.9+/-0.2% (p<0.001) with vildagliptin 50 mg qd, 50 mg bid, and 100 mg qd, respectively. There was no apparent dose-response in the overall population; however, in patients with high baseline HbA1c, there were greater reductions with either 100 mg dose regimen (Delta=-1.3+/-0.2% and -1.4+/-0.2%) compared to 50 mg qd (Delta=-0.8+/-0.1%). Body weight decreased modestly in all groups (by 0.3 to 1.8 kg). The incidence of adverse events was similar across all groups and <or=1.2% of patients in any treatment group reported mild hypoglycemia. In conclusion, vildagliptin monotherapy decreases HbA1c in drug-naïve patients without weight gain and is well tolerated with minimal hypoglycemia.

Characterization of Anaplasma phagocytophilum major surface protein 5 and the extent of its cross-reactivity with A. marginale

Major surface protein 5 (Msp5) of Anaplasma marginale is highly conserved in the genus Anaplasma and the antigen used in a commercially available competitive enzyme-linked immunosorbent assay (cELISA) for serologic identification of cattle with anaplasmosis. This study analyzes the degrees of conservation of Msp5 among various isolates of Anaplasma phagocytophilum and the extent of serologic cross-reactivity between recombinant Msp5 (rMsp5) of Anaplasma marginale and A. phagocytophilum. The msp5 genes from various isolates of A. phagocytophilum were sequenced and compared. rMsp5 proteins of A. phagocytophilum and A. marginale were used separately in an indirect ELISA to detect cross-reactivity in serum samples from humans and dogs infected with A. phagocytophilum and cattle infected with A. marginale. Serum samples were also tested with a commercially available competitive ELISA that uses monoclonal antibody ANAF16C1. There were 100% sequence identities in the msp5 genes among all of the A. phagocytophilum isolates from the United States and a horse isolate from Sweden. Sheep isolates from Norway and dog isolates from Sweden were 99% identical to one another but differed in 17 base pairs from the United States isolates and the horse isolate. Serologic cross-reactivity was identified when serum samples from cattle infected with A. marginale were reacted with rMsp5 of A. phagocytophilum and when serum samples from humans and dogs infected with A. phagocytophilum were reacted with rMsp5 of A. marginale in an indirect-ELISA format. Serum samples from dogs or humans infected with A. phagocytophilum did not cross-react with rMsp5 of A. marginale when tested with the commercially available cELISA. These results suggest that rMsp5 of A. phagocytophilum is highly conserved among United States and European isolates and that serologic distinction between A. phagocytophilum and A. marginale infections cannot be accomplished if rMsp5 from either organism is used in an indirect ELISA.

Vildagliptin therapy reduces postprandial intestinal triglyceride-rich lipoprotein particles in patients with type 2 diabetes

AIMS/HYPOTHESIS

We assessed the effects of vildagliptin, a novel dipeptidyl peptidase IV inhibitor, on postprandial lipid and lipoprotein metabolism in patients with type 2 diabetes.

SUBJECTS, MATERIALS AND METHODS

This was a single-centre, randomised, double-blind study in drug-naive patients with type 2 diabetes. Patients received vildagliptin (50 mg twice daily, n=15) or placebo (n=16) for 4 weeks. Triglyceride, cholesterol, lipoprotein, glucose, insulin, glucagon and glucagon-like peptide-1 (GLP-1) responses to a fat-rich mixed meal were determined for 8 h postprandially before and after 4 weeks of treatment.

RESULTS

Relative to placebo, 4 weeks of treatment with vildagliptin decreased the AUC(0-8h) for total trigyceride by 22+/-11% (p=0.037), the incremental AUC(0-8h) (IAUC(0-8h)) for total triglyceride by 85+/-47% (p=0.065), the AUC(0-8h) for chylomicron triglyceride by 65+/-19% (p=0.001) and the IAUC(0-8h) for chylomicron triglyceride by 91+/-28% (p=0.002). This was associated with a decrease in chylomicron apolipoprotein B-48 (AUC(0-8h), -1.0+/-0.5 mg l(-1) h, p=0.037) and chylomicron cholesterol (AUC(0-8h), -0.14+/-0.07 mmol l(-1) h, p=0.046). Consistent with previous studies, 4 weeks of treatment with vildagliptin also increased intact GLP-1, suppressed inappropriate glucagon secretion, decreased fasting and postprandial glucose, and decreased HbA(1c) from a baseline of 6.7% (change, -0.4+/-0.1%, p<0.001), all relative to placebo.

CONCLUSIONS/INTERPRETATION

Treatment with vildagliptin for 4 weeks improves postprandial plasma triglyceride and apolipoprotein B-48-containing triglyceride-rich lipoprotein particle metabolism after a fat-rich meal. The mechanisms underlying the effects of this dipeptidyl peptidase IV inhibitor on postprandial lipid metabolism remain to be explored.

Malassezia species isolated from the intermammary and preputial fossa areas of horses

BACKGROUND

Malassezia-type yeasts previously have been observed on cytologic examination of the intermammary region of mares that presented with tail-head pruritus; topical antiyeast treatment resolved the pruritus. Further, Malassezia dermatitis has been observed in horses in intertriginous areas such as the udder and prepuce; the species of yeast was not confirmed. It is not known whether healthy mares or male horses can be carriers of this yeast in these body areas.

HYPOTHESIS

Malassezia spp. are present in the intermammary region in healthy mares and the preputial fossa in healthy geldings.

ANIMALS

Eleven healthy horses (5 mares and 6 geldings).

METHODS

Samples of surface material were taken digitally from the intermammary area of 5 mares and the preputial fossa region of 6 geldings. The samples were examined cytologically and were cultured on modified Sabouraud's dextrose agar. The DNA from yeast colonies grown on the agar was extracted, and samples were assayed using fungal generic polymerase chain reaction (PCR) analysis. Amplicons with positive PCR results were sequenced and compared with sequences in the BLAST database search program.

RESULTS

Of 44 attempts at culture, 5 yielded a species identified as Malassezia equi, and 2 yielded M slooffiae. In contrast, of 44 cytologic examinations, yeasts with the morphology of Malassezia spp. were seen in 40 samples.

CONCLUSIONS AND CLINICAL IMPORTANCE

Due to its presence in healthy horses, finding of Malassezia-type yeast on cytologic examination may not incriminate it as a pathogen. Despite difficulty in culturing, cytologic examination was an effective tool to rapidly demonstrate the organism.

Environmental factors associated with Bartonella vinsonii subsp. berkhoffii seropositivity in free-ranging coyotes from northern California

Bartonella vinsonii subsp. berkhoffii is a newly recognized pathogen of domestic dogs and humans. Coyotes (Canis latrans) are considered an important reservoir of this bacterium in the western United States, but its vectors are still unknown. Our objective was to identify environmental factors associated with Bartonella antibody prevalence in 239 coyotes from northern California, using an enzyme-linked immunosorbent assay. In addition, associations were evaluated between B. v. berkhoffii and two pathogens with known vectors and habitat requirements, Dirofilaria immitis and Anaplasma phagocytophilum. Overall, B. v. berkhoffii seroprevalence was 28% (95% confidence interval [CI], 22.3%, 33.7%) and Bartonella seropositive coyotes were more likely than seronegative coyotes to be positive for Anaplasma phagocytophilum (Odds ratio = 3.3; 95% CI = 1.8, 5.9) and Dirofilaria immitis (Odds ratio = 2.1; 95% CI = 1.2, 3.8). The most likely geographic clusters of Bartonella and Dirofilaria overlapped. Bartonella seropositivity was associated with higher precipitation (p = 0.003) and proximity to the coast (p = 0.007) in univariate analysis. The association with precipitation varied with season, based on a logistic regression model.

Alpha cell function in health and disease: influence of glucagon-like peptide-1

Although there is abundant evidence that hyperglucagonaemia plays a key role in the development of hyperglycaemia in type 2 diabetes, efforts to understand and correct this abnormality have been overshadowed by the emphasis on insulin secretion and action. However, recognition that the incretin hormone glucagon-like peptide-1 (GLP-1) exerts opposing effects on glucagon and insulin secretion has revived interest in glucagon, the neglected partner of insulin, in the bihormonal hypothesis. In healthy subjects, glucagon secretion is regulated by a variety of nutrient, neural and hormonal factors, the most important of which is glucose. The defect in alpha cell function that occurs in type 2 diabetes reflects impaired glucose sensing. GLP-1 inhibits glucagon secretion in vitro and in vivo in experimental animals, and suppresses glucagon release in a glucose-dependent manner in healthy subjects. This effect is also evident in diabetic patients, but GLP-1 does not inhibit glucagon release in response to hypoglycaemia, and may even enhance it. Early clinical studies with agents acting through GLP-1 signalling mechanisms (e.g. exenatide, liraglutide and vildagliptin) suggest that GLP-1 can improve alpha cell glucose sensing in patients with type 2 diabetes. Therapeutic approaches based around GLP-1 have the potential to improve both alpha cell and beta cell function, and could be of benefit in patients with a broad range of metabolic disorders.

Vildagliptin, a dipeptidyl peptidase-IV inhibitor, improves model-assessed beta-cell function in patients with type 2 diabetes

AIMS/HYPOTHESIS

The dipeptidyl peptidase IV inhibitor, vildagliptin, increases levels of intact glucagon-like peptide-1 (GLP-1) and improves glycemic control in patients with type 2 diabetes. Although GLP-1 is known to stimulate insulin secretion, vildagliptin does not affect plasma insulin levels in diabetic patients, suggesting that more sophisticated measures are necessary to ascertain the influence of vildagliptin on beta-cell function.

METHODS

This study examined the effects of 28-d treatment with vildagliptin (100 mg, twice daily; n = 9) vs. placebo (n = 11) on beta-cell function in diabetic patients using a mathematical model that describes the insulin secretory rate as a function of glucose levels (beta-cell dose response), the change in glucose with time (derivative component), and a potentiation factor, which is a function of time and may reflect the actions of nonglucose secretagogues and other factors.

RESULTS

Vildagliptin significantly increased the insulin secretory rate at 7 mmol/liter glucose (secretory tone), calculated from the dose response; the difference in least squares mean (deltaLSM) was 101 +/- 51 pmol.min(-1).m(-2) (P = 0.002). The slope of the beta-cell dose response, the derivative component, and the potentiation factor were not affected. Vildagliptin also significantly decreased mean prandial glucose (deltaLSM, -1.2 +/- 0.4 mmol/liter; P = 0.01) and glucagon (deltaLSM, -10.7 +/- 4.8 ng/liter; P = 0.03) levels and increased plasma levels of intact GLP-1 (deltaLSM, +10.8 +/- 1.6 pmol/liter; P < 0.0001) and gastric inhibitory polypeptide (deltaLSM, +43.4 +/- 9.4 pmol/liter; P < 0.0001) relative to placebo.

CONCLUSION

Vildagliptin is an incretin degradation inhibitor that improves beta-cell function in diabetic patients by increasing the insulin secretory tone.

Common virus infections in cats, before and after being placed in shelters, with emphasis on feline enteric coronavirus

The purpose of this study was to determine the origin and subsequent spread of feline calicivirus (FCV), feline herpesvirus (FHV), and feline enteric coronavirus (FECV) in cats relinquished to shelters. FCV was isolated from the oral fauces of 11% of healthy cats upon entry, and isolation rates were highest for kittens (33%). FHV shedding was very low (4%) at the time of entry and occurred mainly in juveniles. FECV shedding was also common among newly relinquished cats (33%), especially older kittens and juveniles (90%). The subsequent spread of all three viruses was rapid and efficient in the shelter environment. Fifteen percent of cats were shedding FCV, 52% FHV, and 60% FECV after 1 week. More detailed studies were done with FECV shedding, which could be accurately quantitated. The amounts of FECV shed by infected cats ranged from 10²to 10¹⁶particles/swab of feces. FECV shedding was several logs higher in young kittens with primary infection than adult cats with primary infections. The mean levels of FECV shedding among adults were the same for primary and chronic infections. Although shelters were not the primary source of these viruses for many relinquished cats, factors intrinsic to the shelter environment were critical in amplifying shedding and spread to susceptible individuals. Extrinsic factors were especially important for the spread of FHV and FECV. FHV shedding rates increased from 4% to 50% in 1 week's time. The speed and magnitude of the increase in FHV shedding suggested that there was reactivation of latent infections as well as acquisition of new infections. FECV shedding increased 10 to 1,000,000 fold in 1 week among cats that were already infected at entry, and more than one-half of initially negative cats were shedding FECV a week later. Feline calicivirus infection was the least likely to spread in the shelter. The infection rate only increased from 11 to 15% in 1 week.

Inflammation and changes in cytokine levels in neurological feline infectious peritonitis

Feline infectious peritonitis (FIP) is a progressive, fatal, predominantly Arthus-type immune-mediated disease that is triggered when cats are infected with a mutant enteric coronavirus. The disease presents variably with multiple organ failure, seizures, generalized effusion, or shock. Neurological FIP is clinically and pathologically more homogeneous than systemic 'wet' or 'dry' FIP; thus, comparison of cytokine profiles from cats with neurological FIP, wet FIP, and non-FIP neurological disease may provide insight into some baseline characteristics relating to the immunopathogenesis of neurological FIP. This study characterizes inflammation and changes in cytokines in the brain tissue of FIP-affected cats. Cellular infiltrates in cats with FIP included lymphocytes, plasma cells, neutrophils, macrophages, and eosinophils. IL-1 beta, IL-6, IL-12, IL-18, TNF-alpha, macrophage inhibitory protein (MIP)-1 alpha, and RANTES showed no upregulation in the brains of control cats, moderate upregulation in neurological FIP cats, and very high upregulation in generalized FIP cats. Transcription of IFN-gamma appeared upregulated in cats with systemic FIP and slightly downregulated in neurological FIP. In most cytokines tested, variance was extremely high in generalized FIP and much less in neurological FIP. Principal components analysis was performed in order to find the least number of 'components' that would summarize the cytokine profiles in cats with neurological FIP. A large component of the variance (91.7%) was accounted for by levels of IL-6, MIP-1 alpha, and RANTES. These findings provide new insight into the immunopathogenesis of FIP and suggest targets for immune therapy of this disease.

Acarologic risk of exposure to emerging tick-borne bacterial pathogens in a semirural community in northern California

An acarologic study was conducted in a semirural community in northern California to determine the relative abundance of, and the prevalence of infection with, three emerging bacterial pathogens in the western black-legged tick (Ixodes pacificus). These included the agents causing Lyme disease (Borrelia burgdorferi), human granulocytic ehrlichiosis [Ehrlichia phagocytophila (formerly Ehrlichia equi)], and human monocytic ehrlichiosis (Ehrlichia chaffeensis). The study area in Sonoma County consisted of two properties each with four residents and an uninhabited adjacent comparison area. Six of the eight residents had been either physician-diagnosed or serodiagnosed previously with Lyme disease, and, of these, one also had been serodiagnosed with human monocytic ehrlichiosis. Direct immunofluorescent/culture assays and bacterial species-specific polymerase chain reaction assays were used to test whole ticks individually for presence of B. burgdorferi and Ehrlichia spp., respectively. Overall, 6.5% of the nymphal (n = 589) and 1.6% of the adult ticks (n = 318) from the same generational cohort were found to contain B. burgdorferi. In contrast, none of 465 nymphs and 9.9% of 202 adults were infected with E. phagocytophila. Excised tissues from another 95 adult ticks yielded a comparable E. phagocytophila infection prevalence of 13.7%. E. chaffeensis was not detected in either nymphal or adult ticks. Using a combination of culture and polymerase chain reaction assays, coinfection of I. pacificus adults with B. burgdorferi and E. phagocytophila was demonstrated for the first time. The marked disparity in the infection prevalence of these pathogens in nymphal and adult ticks suggests that their maintenance cycles are inherently different.

Pharmacologic restoration of the early insulin response in pre-diabetic monkeys controls mealtime glucose excursions without peripheral hyperinsulinaemia

AIMS/HYPOTHESIS

This study sought first to compare the pharmacodynamics and pharmocokinetics of two rapid-onset, rapidly-reversible insulinotropic agents, nateglinide and repaglinide, in pre-diabetic Cynomolgus monkeys and second to use these agents to assess the metabolic effects of early insulin secretion on prandial glucose control.

METHODS

First, equipotent doses of nateglinide (20 mg/kg) and repaglinide (0.1 mg/kg) or vehicle were given intragastrically to overnight-fasted ketamine-anesthetized pre-diabetic Cynomolgus monkeys and samples were obtained for measurement of plasma glucose, insulin, glucagon, NEFA and drug concentrations. Second, nateglinide, repaglinide or vehicle were administered 10 min before a glucose-supplemented liquid meal and prandial glucose and insulin profiles were compared.

RESULTS

Although oral administration of nateglinide and repaglinide elicited similar maximum increments of plasma insulin (+403 and +448 pmol/l, respectively), the effects of nateglinide were more rapidly manifest and less prolonged. With nateglinide, insulin increased within 10 min and returned to baseline within 50 min. After repaglinide, the first increase occurred at 30 min and insulin concentrations remained increased for 3.5 h post-dose. When given 10 min before a meal, nateglinide increased early, but not total insulin release (AUC(0-210)=108 vs 150 nmol/l min for nateglinide and vehicle, respectively) and reduced prandial glucose excursions by 78%. Repaglinide increased total insulin release (AUC(0-210)=298 nmol/l min) and reduced glucose excursions by 53%.

CONCLUSION/INTERPRETATION

Nateglinide is more rapid-acting and rapidly-reversible than is repaglinide. By restoring a more physiologic insulin profile, nateglinide is more effective than repaglinide in controlling prandial glucose excursions with less hyperinsulinaemia.

Evidence for modulated immune response to Anaplasma phagocytophila sensu lato in cats with FIV-induced immunosuppression

Human granulocytic ehrlichiosis (HGE) is an emerging infectious disease in which some patients experience unusual opportunistic infections. In this study, cats infected with the HGE agent, Anaplasma phagocytophila s.l., had clinical granulocytic ehrlichiosis (GE), anti-nuclear antibodies and increased IFN-gamma mRNA. In FIV-immunosuppressed cats with GE, there was upregulated IL-10 transcription but not IFN-gamma. Cats with FIV had poor response to vaccines, regardless of GE status. This preliminary report demonstrates that cats with FIV-infection make a good model of ehrlichiosis in an immunocompromised host, and that viral immunosuppression may not increase the severity of ehrlichiosis but may attenuate immune responses to the pathogen.

Feline inflammatory polyps: historical, clinical, and PCR findings for feline calici virus and feline herpes virus-1 in 28 cases

Inflammatory polyps are associated with significant aural or nasopharyngeal disease in cats. It has been proposed that chronic viral infection may induce the masses. Ventral bulla osteotomy (VBO) is usually recommended for definitive therapy but removal of masses from the nasopharynx or external ear canal by traction/avulsion is also used. A retrospective study of 28 cats with inflammatory polyps was conducted to correlate recurrence with mode of therapy. Tissues from 41 polyps were assayed for feline calicivirus and feline herpesvirus-1 by RT-PCR and PCR, respectively. Of the 14 cats initially treated by traction/avulsion, recurrence was detected in five of nine cats with radiographic evidence of bulla disease but none of the cats with normal bullae. Traction/avulsion is a reasonable treatment for inflammatory polyps if the bullae are radiographically normal. Failure to detect feline calicivirus and feline herpesvirus-1 suggests that tissue persistence of these viruses is not associated with the development of inflammatory polyps.

Clinical, microscopic, and molecular aspects of canine leproid granuloma in the United States

Leproid granulomas from seven dogs in the United States were evaluated. Gross characteristics included nodular and ulcerated dermal and subcutaneous lesions primarily on the caudal aspects of the pinnae and to a lesser extent on the muzzle, face, and forelimbs. In all except one dog, there was complete regression of the lesions within 6 months, either with no therapy or after surgical resection. Cytology or histopathology revealed pyogranulomatous inflammation with few to many acid-fast mycobacterial bacilli within macrophages. The organisms could not be cultivated in vitro. DNA sequencing of part of the 16S ribosomal RNA gene region revealed 99-100% homology among fragments from five of these dogs and fragments from dogs in the south Pacific. This syndrome occurs in dogs in North America and the prognosis is excellent, in contrast to the prognosis for rapid-growing or tuberculous mycobacteriosis.