Nanoparticle-Hydrogel Systems Containing Platensimycin for Local Treatment of Methicillin-Resistant Staphylococcus aureus Infection.

Skin and soft tissue infections require effective and sustained topical administration. Platensimycin (PTM) is a natural drug lead that targets bacterial fatty acid synthases and has a great potential to treat infections caused by methicillin-resistant Staphylococcus aureus (MRSA). To facilitate the use of PTM against local MRSA infections, we prepared polyacrylamide hydrogels containing polyamidoamine (PAMAM)/PTM nanoparticles (NP-gel(PTM)) for the controlled release of PTM. NP-gel(PTM) can continuously inhibit the growth of MRSA and its biofilm formation in simulated drug flow models in vitro. In situ implantation of NP-gel(PTM) could treat MRSA-infected subcutaneous soft tissues without toxicity. For MRSA-infected skin wounds, NP-gel(PTM) not only showed strong anti-MRSA activity but also accelerated more wound healing than the widely used antibiotic mupirocin. Collectively, PTM is expected to be used in this safe and effective NP-gel delivery platform for the treatment of local infections, which might help to alleviate the current antibiotic resistance crisis.

Effect of stevia aqueous extract on the antidiabetic activity of saxagliptin in diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Stevia rebaudiana Bertoni is a perennial herb that belongs to the Asteraceae family. It is a natural sweetener plant known as "Sweet Leaf", "Sweet Herbs" and "Honey Leaf", which is estimated to be 300 times more sweetening than sugar cane. Stevia has been used as a traditional treatment for diabetes in many countries for hundreds of years. Several animal studies referred to the antihyperglycemic activity of stevia. However, the combined use of stevia with saxagliptin has not been studied so far, so this study has been done. The aim of the present study was to evaluate the antihyperglycemic effect of stevia alone and in combination with saxagliptin. MATERIALS AND METHODS: Diabetes was induced in rats by i.p. injection of streptozotocin and nicotinamide. Animals were divided into five groups, each contains eight rats. Group I: included negative controland group II: included diabetic control that received saline. Group III: included diabetic rats that received 400 mg/kg/day stevia aqueous extract. Group IV: included diabetic rats that received saxagliptin 10 mg/kg/day. Group V: included diabetic rats that received stevia 400 mg/kg + saxagliptin 10 mg/kg. Food and water intake were measured daily while body weight was measured weekly. After 3 weeks animals were sacrificed and blood and tissue samples were collected. Fasting blood glucose (FBG), serum insulin, serum dipeptidylepeptidase-4 (DPP-4), TC, TGs, LDL, HDL, GSH and MDA were measured in treated and control rats by colorimetric and ELISA methods. RESULTS: Both stevia and saxagliptin significantly reduced food, water intake, body weight and FBG. Stevia with saxagliptin produced more significant decrease in FBG. While serum insulin increased significantly in stevia, saxagliptin treated groups and their combination. Serum DPP-4 decreased significantly in all treated groups, concerning lipid profile, stevia and saxagliptin notably lowered TC, TGs, and LDL and increased HDL. Both stevia and saxagliptin remarkably decreased MDA and increased GSH compared to diabetic rats. In addition, stevia significantly improved the antidiabetic effects of saxagliptin. CONCLUSION: Stevia has an antihyperglycemic effect and could enhance the antidiabetic activity of saxagliptin. DPP-4 attenuation, antihyperlipidemic and antioxidant activity as well as improvement of insulin sensitivity may be involved in the antidiabetic action of stevia.

Impact of baseline characteristics on glycemic effects of add-on saxagliptin or acarbose to metformin therapy: Subgroup analysis of the SMART study in Chinese patients with type 2 diabetes mellitus.

AIMS/INTRODUCTION: This secondary analysis of the 24-week SMART study examined the efficacy of add-on saxagliptin or acarbose to metformin across different patient subgroups with type 2 diabetes mellitus, based on baseline characteristics. MATERIALS AND METHODS: Randomized patients (n = 481) were classified into subgroups based on their baseline age (<65, ≥65 years), body mass index (BMI; <24, 24-<28, ≥28 kg/m2 ), glycated hemoglobin (HbA1c; <8%, 8-<9%, 9-<10%, ≥10%) and renal function (creatinine clearance 50-<80, ≥80 mL/min). Treatment effects on primary outcome (HbA1c) and key secondary outcomes of fasting plasma glucose (FPG), 2-h postprandial glucose and homeostatic model assessment of ß-cell function were assessed across patient subgroups. RESULTS: For saxagliptin, reductions in HbA1c from baseline to week 24 were consistent across different subgroups regardless of baseline age, body mass index, HbA1c and renal function (range -0.66 to -1.16%). Saxagliptin was associated with consistent reductions in FPG (-0.60 to -1.33 mmol/L) and 2-h postprandial glucose (-0.48 to -1.95 mmol/L) across the majority of subgroups studied. The efficacy of acarbose on FPG attenuated progressively with increasing baseline HbA1c (+0.86 to -1.43 mmol/L); an increase from baseline FPG was observed in patients with HbA1c >9%. The effect of acarbose on postprandial glucose was also variable (+0.23 to -3.38 mmol/L). CONCLUSIONS: As add-on to metformin, both saxagliptin and acarbose reduced HbA1c regardless of baseline HbA1c, age, body mass index and renal function; however, only saxagliptin was effective at a stable glycemic control (FPG and PPG). The efficacy of acarbose on FPG and PPG was significantly attenuated in patients with higher baseline HbA1c (≥8%).

A novel JAK inhibitor, peficitinib, demonstrates potent efficacy in a rat adjuvant-induced arthritis model.

The Janus kinase (JAK) family of tyrosine kinases is associated with various cytokine receptors. JAK1 and JAK3 play particularly important roles in the immune response, and their inhibition is expected to provide targeted immune modulation. Several oral JAK inhibitors have recently been developed for treating autoimmune diseases, including rheumatoid arthritis (RA). Here, we investigated the pharmacological effects of peficitinib (formerly known as ASP015K), a novel, chemically synthesized JAK inhibitor. We found that peficitinib inhibited JAK1 and JAK3 with 50% inhibitory concentrations of 3.9 and 0.7 nM, respectively. Peficitinib also inhibited IL-2-dependent T cell proliferation in vitro and STAT5 phosphorylation in vitro and ex vivo. Furthermore, peficitinib dose-dependently suppressed bone destruction and paw swelling in an adjuvant-induced arthritis model in rats via prophylactic or therapeutic oral dosing regimens. Peficitinib also showed efficacy in the model by continuous intraperitoneal infusion. Area under the concentration versus time curve (AUC) at 50% inhibition of paw swelling via intraperitoneal infusion was similar to exposure levels of AUC at 50% inhibition via oral administration, implying that AUC might be important for determining the therapeutic efficacy of peficitinib. These data suggest that peficitinib has therapeutic potential for the oral treatment of RA.

Novel Oral Therapies for Psoriasis and Psoriatic Arthritis.

Several classes of new oral therapy are in use or in development for the treatment of psoriasis. Despite the high efficacy of biologics, new oral therapies remain important as patients generally prefer this mode of administration and they offer an alternative risk-benefit profile. In this review, we discuss the novel modes of action of these drugs, including modulation of cellular pathways involving diverse targets such as Janus kinase, phosphodiesterase 4, sphingosine 1-phosphate, A3 adenosine receptor and rho-associated kinase 2. We review the available evidence around licensed drugs (apremilast) and drugs that are advanced (tofacitinib) or early (ponesimod, baricitinib, peficitinib, INCB039110, CF101, KD025) in the development pipeline. The key limitations of these oral therapies are their modest efficacy profile (apremilast, ponesimod) and the limitations of their safety profile (tofacitinib, ponesimod), while the evidence for the early pipeline drugs are at phase II level only. Potential niches of current unmet needs include apremilast for patients with concomitant psoriatic arthritis, as combination treatments with biologic therapies, and/or for patients in whom multiple biologic therapies have failed due to immunogenicity and secondary inefficacy. The present knowledge gap regarding these novel drugs includes the need for longer clinical trials or observational studies to evaluate safety, and randomised phase III trials for the early pipeline drugs. We conclude that further research and data are necessary to conclusively establish the role of these agents in the current psoriasis treatment paradigm.

Saxagliptin is similar in glycaemic variability more effective in metabolic control than acarbose in aged type 2 diabetes inadequately controlled with metformin.

This study compared the effects on glycaemic variability and glucose control between saxagliptin and acarbose as add-on therapies for aged T2DM inadequately controlled with metformin alone. The results showed that compared with acarbose-metformin, saxagliptin-metformin was more effective in glucose control with similar glycaemic variability.

Preclinical efficacy of the synthetic retinoid ST1926 for treating adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATL) is an aggressive neoplasm caused by human T-cell leukemia virus type 1 (HTLV-1). The HTLV-1 oncoprotein Tax plays an important role in ATL pathogenesis. ATL carries a poor prognosis due to chemotherapy resistance, stressing the need for alternative therapies. Here, we investigate the preclinical efficacy of the synthetic retinoid ST1926 in ATL and peripheral T-cell lymphomas. Clinically achievable concentrations of ST1926 induced a dramatic inhibition of cell proliferation in malignant T-cell lines and primary ATL cells with minimal effect on resting or activated normal lymphocytes. ST1926 induced apoptosis, DNA damage, and upregulation of p53 proteins in malignant T cells, whereas it caused an early downregulation of Tax proteins in HTLV-1-positive cells. In murine ATL, oral treatment with ST1926 prolonged survival and reduced leukemia cell infiltration, white blood cell counts, and spleen mass. In spleens of ST1926-treated animals, p53 and p21 proteins were upregulated, poly (ADP-ribose) polymerase was cleaved, and Tax transcripts were reduced. These results highlight the promising use of ST1926 as a targeted therapy for ATL.

Vascular origin of vildagliptin-induced skin effects in Cynomolgus monkeys: pathomechanistic role of peripheral sympathetic system and neuropeptide Y.

The purpose of this article is to characterize skin lesions in cynomolgus monkeys following vildagliptin (dipeptidyl peptidase-4 inhibitor) treatment. Oral vildagliptin administration caused dose-dependent and reversible blister formation, peeling and flaking skin, erosions, ulcerations, scabs, and sores involving the extremities at ≥5 mg/kg/day and necrosis of the tail and the pinnae at ≥80 mg/kg/day after 3 weeks of treatment. At the affected sites, the media and the endothelium of dermal arterioles showed hypertrophy/hyperplasia. Skin lesion formation was prevented by elevating ambient temperature. Vildagliptin treatment also produced an increase in blood pressure and heart rate likely via increased sympathetic tone. Following treatment with vildagliptin at 80 mg/kg/day, the recovery time after lowering the temperature in the feet of monkeys and inducing cold stress was prolonged. Ex vivo investigations showed that small digital arteries from skin biopsies of vildagliptin-treated monkeys exhibited an increase in neuropeptide Y-induced vasoconstriction. This finding correlated with a specific increase in NPY and in NPY1 receptors observed in the skin of vildagliptin-treated monkeys. Present data provide evidence that skin effects in monkeys are of vascular origin and that the effects on the NPY system in combination with increased peripheral sympathetic tone play an important pathomechanistic role in the pathogenesis of cutaneous toxicity.

Mechanisms of action of ladasten: activation of gene expression for neurotrophins and mitogen-activated kinases.

We studied the effects of single treatment with ladasten (50 mg/kg) on the content of effector kinases of the mitogen-activated cascade (ERK1/ERK2), pERK1/ERK2 activity (Thr202/Tyr204), and expression of genes for neurotrophic factors BDND and NGF in the striatum, hypothalamus, and hippocampus of rats.

[Effects of ionotropic glutamate receptor channel blockers on the development of audiogenic seizures in Krushinski-Molodkina rats].

The action of noncompetitive blockers of glutamate receptors has been investigated on Krushinski-Molodkina rats genetically-prone to audiogenic seizures. The selective blockers of NMDA receptor channels, memantine and IEM-1921, and their dicationic homologues, IEM-1925 and IEM-1754, capable of blocking in varying degrees both NMDA and Ca-permeable AMPA receptor channels, were studied. The drugs were injected intramuscularly to rats with the different time intervals (30 min, 1, 2 or 3 hours) before sound signal. The effects of the drugs on latent period of initial locomotor activity provoked by audio stimulation (8 kHz sine-wave tone, 90 dB volume), the appearance of clonic convulsions of different intensities, and, finally, tonic convulsions with limb and tail extension were evaluated. Within 30 min after injection IEM-1921 at a dose of 5 mg/kg, 33% of rats manifested a complete absence of convulsive reactions to sound, and in 59% of rats audiogenic seizures occured only in the form of motor excitation without a generalized clonic-tonic convulsions. Memantine at a dose of 5 mg/kg did not cause a complete blockade of seizures, but after 1 h of injection in 50% of the rats and after 2 h in 70% of rats a weakening of the audiogenic seizures to the level of motor excitation only was observed. After 3 hrs after administration of blockers its anticonvulsive action weakened significantly (p < 0.01). Dicationic blockers that block both NMDA and AMPA/kainate receptors, IEM-1925 (in doses of 0.001-20.0 mg/kg) and IEM-1754 (0.025-50.0 mg/kg), did not affect audiogenic clonic-tonic convulsive reactions. The involvement of activation of NMDA and calcium permeable AMPA/kainate receptors in the pathogenesis of audiogenic seizures is discussed.

CD26/DPP-4 inhibition recruits regenerative stem cells via stromal cell-derived factor-1 and beneficially influences ischaemia-reperfusion injury in mouse lung transplantation.

OBJECTIVES: The CD26 antigen is a transmembrane glycoprotein that is constitutively expressed on activated lymphocytes and in pulmonary parenchyma. This molecule is also identified as dipeptidyl peptidase-4 (DPP-4) that cleaves a host of biologically active peptides. Here, we aimed to identify an important substrate of CD26/DPP-4-stromal cell-derived factor-1 (SDF-1/CXCL12)-as a key modulator for stem-cell homing together with its receptor CXCR4 in response to ischaemic injury of the lung. METHODS: Orthotopic single lung transplantation (Tx) was performed between syngeneic C57BL/6 mice. Inhibition of CD26/DPP-4 activity in recipients was achieved using vildagliptin (10 mg/kg, every 12 h) subcutaneously, and 6 h ischaemia time was applied prior to implantation. Forty-eight hours after Tx, lung histology, SDF-1 levels (enzyme-linked immunosorbent assay) in lung, spleen and plasma, and expression of the SDF-1 receptor CXCR4 in blood and lung were assessed. Homing of regenerative progenitor cells to the transplanted lung was evaluated using fluorescent-activated cell sorting. RESULTS: Compared with untreated lung transplanted mice, systemic DPP-4 inhibition of Tx recipients resulted in an increase in protein concentration of SDF-1 in plasma, spleen and lung. Concordantly, the frequency of cells bearing the SDF-1 receptor CXCR4 rose significantly in the circulation and also in the lungs of DPP-4-inhibited recipients. We found co-expression of CXCR4/CD34 in the grafts of animals treated with vildagliptin, and the stem-cell markers Flt-3 and c-kit were present on a significantly increased number of cells. The morphology of grafts from DPP-4 inhibitor-treated recipients revealed less alveolar oedema when compared with untreated recipients. CONCLUSIONS: Targeting the SDF-1-CXCR4 axis through CD26/DPP-4 inhibition increased the intragraft number of progenitor cells contributing to the recovery from ischaemia-reperfusion lung injury. Stabilization of endogenous SDF-1 is achievable and may be a promising strategy to intensify sequestration of regenerative stem cells and thus emerges as a novel therapeutic concept.

Stability and bioactivity studies on dipeptidyl peptidase IV resistant glucogan-like peptide-1 analogues.

Glucagon-like peptide-1 (GLP-1) was once considered as an ideal anti-diabetic candidate for its important role in maintaining glucose homeostasis through the regulation of islet hormone secretion, as well as hepatic and gastric function. However, the major therapeutic obstacle for using native GLP-1 as a therapeutic agent is its very short half-life primarily due to their degradation by the enzyme dipeptidyl peptidase IV (DPP-IV). In this study, GLP-1 analogues with modifications in amino acid site 8, 22 and 23 were synthesized using solid phase peptide synthesis. Resistance of these analogues to DPP-IV cleavage was investigated in vitro by incubation of the peptides with DPP-IV or human plasma. Glucoregulating efficacy of the analogues was evaluated in normal Kunming mice using intraperitoneal glucose tolerance model. Glucose lowering effect of combination therapy (analogue plus Vildagliptin) has also been studied. In vitro studies showed that the modified analogues were much more stable than native GLP-1 (nearly 100% of the peptide keep intact after 4 h incubation). In vivo biological activity evaluation revealed that His8-EEE (the most potent GLP-1 analogues in this study) exhibited significantly improved glycemic control potency (approximately 4.1-fold over saline and 2.5-fold over GLP-1) and longer time of active duration (at least 5 h). Combination therapy also showed the trend of its superiority over mono-therapy. Modified analogues showed increased potency and biological half-time compared with the native GLP-1, which may help to understand the structure-activity relationship of GLP-1 analogues.

Time course of histone deacetylase 1 and acetylated H3 and H4 histones in the brain of rats treated with ladasten.

We studied the effects of single intragastric administration of ladasten in a dose of 50 mg/kg on the time course of histone deacetylase 1 (HDAC1) and levels of acetylated histones H3 (Lys9) and H4 (Lys8) in the striatum, hippocampus, and hypothalamus. Ladasten reduced HDAC1 level in rat striatum and hippocampus and modified H3acK9 and H4acK8 levels in various structures of rat brain.

Synthesis and structure-activity relationships of potent and orally active 5-HT4 receptor antagonists: indazole and benzimidazolone derivatives.

A series of indole-3-carboxamides, indazole-3-carboxamides, and benzimidazolone-3-carboxamides was synthesized and evaluated for antagonist affinity at the 5-HT4 receptor in the rat esophagus. The endo-3-tropanamine derivatives in the indazole and benzimidazolone series possessed greater 5-HT4 receptor affinity than the corresponding indole analogues. 5-HT4 receptor antagonist affinity was further increased by alkylation at N-1 of the aromatic heterocycle. In a series of 1-isopropylindazole-3-carboxamides, replacement of the bicyclic tropane ring system with the monocyclic piperidine ring system or an acyclic aminoalkylene chain led to potent 5-HT4 receptor antagonists. In particular, those systems in which the basic amine was substituted with groups capable of forming hydrogen bonds showed increased 5-HT4 receptor antagonist activity. While some of these compounds displayed high affinity for other neurotransmitter receptors (in particular, 5-HT3, alpha1, and 5-HT2A receptors), as the conformational flexibility of the amine moiety increased, the selectivity for the 5-HT4 receptor also increased. From this series of compounds, we identified LY353433 (1-(1-methylethyl)-N-[2-[4-[(tricyclo[3.3.1.1(3, 7)]dec-1-ylcarbonyl)amino]-1-piperidinyl]ethyl]-1H-indazole-3- carboxamide) as a potent and selective 5-HT4 receptor antagonist with clinically suitable pharmacodynamics.

K-ATP-blocking diuretic PNU-37883A reduces plasma renin activity in dogs.

We determined the effects of the K-adenosine triphosphate (ATP)-blocking diuretic PNU-37883A on plasma renin activity (PRA) in conscious and anesthetized dogs. In conscious dogs, oral PNU-37883A (6-60 mg/kg) was less potent than hydrochlorothiazide (0.15-1.5 mg/kg) and furosemide (FURO; 0.3-3.0 mg/kg) but exhibited high natriuretic efficacy with little kaliuresis. Unlike the standard diuretics, PNU-37883A reduced PRA by 46-76%, and its high dose minimally affected 24-h urinary aldosterone excretion. PNU-37883A, 1 mg/kg i.v., also blunted the hyperreninemia induced by 1 mg/kg i.v. FURO. In cannulated dogs, 10 mg/kg i.v. PNU-37883A maximally increased fractional Na+ clearance 140% and reduced PRA 76%, but these effects were accompanied by a mean 13 mm Hg pressor effect. In anesthetized dogs, renal artery-infused PNU-37883A (3 mg/kg/h i.r.a.) increased Na+ excretion and reduced renal venous PRA independent of hemodynamics, whereas half this dosage selectively reduced renal venous PRA and renin release, independent of hemodynamics and natriuresis. These data demonstrate that the K-ATP blocker diuretic PNU-37883A reduces PRA in dogs after oral, i.v., and i.r.a. administration and could be a useful pharmacologic agent for exploring the role of K-ATP channels in regulating renin release.

[Effect of lipid emulsifiers on the properties of organoperfluorine emulsions]. / Vliianie lipidnykh émul'gatorov na svoistva émul'sii perftor- organicheskikh soedinenii.

The preparation and application of a new type of organoperfluorine (OPF) emulsions with lipids serving as emulsifiers, their biological and physicochemical properties are discussed. The first-generation emulsions with the nonionic emulsifier, ethylene and propylene oxide blockpolymer, were found to be complementary active and to affect the system's biological properties. Interactions between OPF and phospholipids are analysed. The compositions of the new type OPF emulsions are given, of which perfluoroctyl bromide and perfluoromethyl adamantine emulsions are shown to be currently of most interest, since they are stable at room temperature and exhibit somewhat superior physicochemical and biological parameters. A conclusion is derived that the developed lipid-based OPF emulsions have good clinical prospects.