Preclinical evaluation of abuse potential of the peripherally-restricted kappa opioid receptor agonist HSK21542.

HSK21542 is a peripherally-restricted kappa opioid receptor (KOR) agonist developed for pain treatment. Because of the CNS pharmacological concern of opioid receptor activation, such as physical dependence and addiction potential, an assessment of abuse potential of HSK21542 was required prior to marketing approval. The preclinical abuse potential assessments for HSK21542 included the following studies: 1) intravenous self-administration study to explore the relative reinforcing efficacy in rats self-administering remifentanil; 2) rat drug discrimination study to examine the pharmacological similarity of the interoceptive or subjective effects of HSK21542 in rats discriminating pentazocine; 3) rat conditioned place preference (CPP) paradigm to test the rewarding effects; 4) rat natural physical dependence-spontaneous withdrawal study in rats chronically treated with HSK21542; 5) naloxone-precipitated withdrawal assay following chronic HSK21542 exposure to evaluate its physical dependence potential. The results showed that HSK21542 was devoid of behavioral evidence of positive reinforcing effect and did not share similar discriminative stimulus effects with pentazocine. HSK21542 also did not produce CPP in rats. In addition, HSK21542 did not produce spontaneous withdrawal or naloxone-precipitated withdrawal in rats with chronic treatments. Collectively, these preclinical findings suggest that HSK21542 has no abuse potential in animals, which demonstrate low abuse potential in humans.

The repeated administration of rhIL-12 for 14 weeks in rhesus monkeys: A toxicity assessment.

Interleukin-12 (IL-12) is known to exert antitumor immune effects by promoting the activation and proliferation of T cells and NK cells within the immune system. However, clinical trials have observed systemic toxicity associated with the administration of IL-12. This has shelved development plans for its use as a cancer therapeutic drug. Therefore, it is critical that we perform a systematic evaluation of the toxicity and safety of repeated IL-12 administration. In this study, we conducted a comprehensive evaluation of the toxicity and safety of repeated rhIL-12 (recombinant human interleukin-12) administration in rhesus monkeys by assessing its effects on the immune system, organ function, and vital signs. Rhesus monkeys were subcutaneously injected with 0.5, 2.5, and 12.5 µg/kg of rhIL-12 for up to for 14 consecutive weeks. The low dose exhibited no signs of toxicity, whereas animals receiving higher doses displayed symptoms such as loose stools, reduced activity, anemia, and elevated liver function indicators (AST and TBIL). Following three administrations of 12.5 µg/kg, high dosing was adjusted to 7.5 µg/kg due to manifestations of symptoms like loose stools, decreased activity, and huddling in the cage. Furthermore, rhesus monkeys exhibited marked immunogenic responses to recombinant human interleukin-12 (rhIL-12). However, based on overall study findings, the No Observed Adverse Effect Level (NOAEL) for the subcutaneous injection of rhIL-12, when repeatedly administered for 3 months in rhesus monkeys, was considered to be 0.5 µg/kg. The Highest Non-Severely Toxic Dose (HNSTD) was considered to be 7.5 µg/kg.

Zero-Order Release of Gossypol Improves Its Antifertility Effect and Reduces Its Side Effects Simultaneously.

Gossypol was considered a promising male contraceptive but finally failed due to two side effects: hypokalemia and the irreversibility of its contraceptive effect. Here we demonstrate that sustained zero-order release could be a solution for these problems. The in vitro release of gossypol from gossypol/PEG layer-by-layer films follows a perfect zero-order kinetics. In vivo tests indicate that the films can maintain the plasma drug concentration constant in male SD rats for ∼20 days for a 30-bilayer film. The plasma drug concentration is 2 orders of magnitude lower than the peak plasma drug concentration when administered orally and the daily dose is >50-fold lower than the commonly used contraceptive oral dose. However, significant antifertility effects were still observed. Furthermore, hypokalemia was not observed, and the antifertility effects can be reversed after a recovery period. The results suggest that zero-order release can significantly improve the desired antifertility effect of gossypol and, meanwhile, significantly reduce its side effects. We envision the drug could be developed to be an effective, safe, and reversible male contraceptive by zero-order release.

[Efficient method for analyzing absorbed ingredients of traditional Chinese medicine genitana macrophyllae radix].

In present study, a method for analyzing the absorbed ingredients of traditional Chinese medicine QinJiao has been developed. A rat everted gut sac (EGS) model has been established, and the transporting capacity of gut sacs was identified by histological examinations. The ingredients including loganic acid, sweroside, gentiopicroside, and swertiamarian in serosal solution absorbed by active transport of rat everted ileum and jejunum from Qinjiao extraction were determined using an HPLC method. Histological integrality of the gut sacs remains perfect and the active transport activity of them is normal within 45 min of the experiment. The HPLC method employed in this study presents high specificity and good correlation. The relative standard deviation of precision of this method is less than 5.5%. Extraction recovery of samples is more than 90%. And stability of the samples in room temperature is perfect. Eight ingredients of Qinjiao absorbed in serosal solution are identified. Furthermore, concentration of Qinjiao extraction significantly affects accumulated absorption and absorption coefficient of the ingredients. However, there is no significant impact on the accumulated absorption and absorption coefficient by diverse of everted gut sections. From above, the EGS techniques might be an efficient method, which can be employed for investigation of absorbed ingredients of Traditional Chinese Medicines.

Reducing Hinge Flexibility of CAR-T Cells Prolongs Survival In Vivo With Low Cytokines Release.

Chimeric antigen receptor (CAR)-modified T cells targeting CD19 demonstrate unparalleled responses in B cell malignancies. However, high tumor burden limits clinical efficacy and increases the risk of cytokine release syndrome and neurotoxicity, which is associated with over-activation of the CAR-T cells. The hinge domain plays an important role in the function of CAR-T cells. We hypothesized that deletion of glycine, an amino acid with good flexibility, may reduce the flexibility of the hinge region, thereby mitigating CAR-T cell over-activation. This study involved generating a novel CAR by deletion of two consecutive glycine residues in the CD8 hinge domain of second-generation (2nd) CAR, thereafter named 2nd-GG CAR. The 2nd-GG CAR-T cells showed similar efficacy of CAR expression but lower hinge flexibility, and its protein affinity to CD19 protein was lower than that of 2nd CAR-T cells. Compared to the 2nd CAR-T cells, 2nd-GG CAR-T cells reduced proinflammatory cytokine secretion without diminishing the specific cytotoxicity toward tumor cells in vitro. Furthermore, 2nd-GG CAR-T cells prolonged overall survival in an immunodeficient mouse model bearing NALM-6 when tumor burden was high. This study demonstrated that a lower-flexibility of CD8α hinge improved survival under high tumor burden and reduced proinflammatory cytokines in preclinical studies. While there is potential for improved safety and efficacy, yet this needs validation with clinical trials.

Supramolecular trap for catching polyamines in cells as an anti-tumor strategy.

Polyamines are essential for the growth of eukaryotic cells and can be dysregulated in tumors. Here we describe a strategy to deplete polyamines through host-guest encapsulation using a peptide-pillar[5]arene conjugate (P1P5A, P1 = RGDSK(N3)EEEE) as a supramolecular trap. The RGD in the peptide sequence allows the molecule to bind to integrin αvß3-overexpressing tumor cells. The negative charged glutamic acid residues enhance the inclusion affinities between the pillar[5]arene and cationic polyamines via electrostatic interactions and facilitate the solubility of the conjugate in aqueous media. The trap P1P5A efficiently encapsulates polyamines with association constants of 105-106 M-1. We show that P1P5A has a wide spectrum of antitumor activities, and induces apoptosis via affecting the polyamine biosynthetic pathway. Experiments in vivo show that P1P5A effectively inhibits the growth of breast adenocarcinoma xenografts in female nude mice. This work reveals an approach for suppressing tumor growth by using supramolecular macrocycles to trap polyamines in tumor cells.

Angle Stable Interlocking Intramedullary Nails for Tibial Plateau Fractures.

OBJECTIVE: Angle stable interlocking intramedullary nail (ASIN), a novel technique, has rarely been used for treatment of tibial plateau fractures (TPF). This retrospective study was designed to introduce this novel technique, ASIN, as well as to describe the initial experience and verify the effectiveness when ASIN was used for the management for TPF. METHODS: A cohort of 19 cases with closed TPF aged from 18-70 years with at least 23 months follow-up from November 2008 to September 2013 was analyzed retrospectively. All patients underwent the ASIN procedure, which was performed by the same group of surgeons. Perioperative and postoperative parameters like the measurement of radiographic pictures, surgical data, and clinical function were recorded including the changes in treatment. A modified Hohl-Luck radiological and functional score combined with the Hospital for Special Surgery (HSS) score were applied to evaluate the final results and to provide reliable data through the whole procedure when applying the ASIN procedure. RESULTS: The patients were followed up regularly for an average of 26.3 (range, 23-34) months. All patients achieved a bony union at an average of 15.1 weeks with no incidences of malunion, nonunion, or infection. Anatomical reduction of the articular surface was obtained in 16 patients. No secondary failure of fixation occurred. The mean postoperative knee flexion was 122.9°. The modified Hohl-Luck radiological and functional score was excellent and good, respectively, in 16 patients. The mean HSS score was 89.4. CONCLUSION: The angle stable interlocking intramedullary nail system turned out to be a viable alternative protocol in the treatment of tibia plateau fractures and provided satisfactory results, with good fracture reduction, biomechanical fixation, low rates of complications, and passable postoperative knee function.

Toxic effects of Fusarium mycotoxin butenolide on rat myocardium and primary culture of cardiac myocytes.

Mycotoxin toxicosis has been implicated in the etiopathogenesis of Keshan disease (KD), an endemic cardiomyopathy prevailing in some regions of China. Butenolide (4-acetamido-4-hydroxy-2-butenoic acid gamma-lactone, CAS No. 16275-44-8), a mycotoxin produced by several Fusarium species such as Fusarium tricinctum and Fusarium graminearum, is frequently detected from the cereals in the endemic areas of KD. The present study is undertaken to investigate whether this mycotoxin can induce myocardial damage. Exposure of primary culture of cardiac myocytes to butenolide resulted in significant cytotoxicity, manifested by changes in cell morphology and decreases in cell viability. Consistent with the in vitro findings, distinct myocardial toxicity in vivo was observed after administration of rats by gavage with butenolide (10 and 20 mg/kg/day) for 2 months, and the myocardial injuries were characterized by focal necrosis of myocardium and fragmentation of myofiber. Butenolide also induced significant oxidative damage to the myocardium in vitro evidenced by a concentration-dependent lipid peroxidation in the myocardial homogenates, whereas antioxidants superoxide dismutase (SOD), N-acetylcysteine (NAC) and glutathione (GSH) provided significant protections against this oxidative effect. Taken together, these results clearly reveal that butenolide possesses the potential to induce myocardial toxicity. The present findings may reinforce the hypothesis that toxicosis by mycotoxins is one of the etiological factors for KD.

Metallothionein protects against doxorubicin-induced cardiomyopathy through inhibition of superoxide generation and related nitrosative impairment.

Metallothionein (MT) has been shown to be an effective protector against DOX-induced cardiomyopathy, however the involved precise mechanisms are still unknown. The present study was undertaken to clarify whether the inhibition of superoxide generation and related nitrosative damage were involved in the metallothionein attenuation of DOX-induced cardiac injury. MT-I/II null (MT-/-) mice and corresponding wild-type mice (MT+/+) were pretreated with either saline or zinc (300 micromol/kg, s.c., once a day for 2 days) prior to a single dose of DOX (15 mg/kg, i.p.) or equal volume of saline. Animals were sacrificed on the 4th day after DOX administration and samples were collected for further analyses. DOX caused remarkable cardiac damage in both MT+/+ and MT-/- mice as demonstrated by biochemical and histopathological alterations. Zinc pretreatment significantly increased the cardiac MT levels and therefore inhibited the cardiac toxic effects of DOX only in MT+/+ mice, but not in MT-/- mice. Furthermore, elevated formation of superoxide and peroxynitrite were obviously observed after DOX treatment, while these elevation were prevented by MT induction by zinc in MT+/+ mice, but not in MT-/- mice. These findings suggest that metallothionein induction by zinc exhibits protective effects on the cardiac toxicology of DOX, which might be mediated through the prevention of superoxide generation and related nitrosative impairment.

Direct effects of lead (Pb2+) on the relaxation of in vitro cultured rat aorta to acetylcholine.

Lead (Pb(2+)) exposure is related to increased blood pressure or hypertension of human or animals. Abnormal vascular relaxant responses of low level Pb(2+) exposed animals were reported by several studies. However, it is difficult to tell whether these effects were induced directly by Pb(2+) or not. In this study we hypothesized that Pb(2+) can directly affect the relaxation of vessels. Male Wistar rat aortae were removed and cultured in PMRI 1640 with 1 ppm Pb(2+) (4.8 microM lead acetate) for 0.5, 6, 12 and 24h, and then their responses to acetylcholine (ACh) and sodium nitroprusside (SNP) were examined. After incubated for 24h, the relaxation induced by ACh was significantly decreased in Pb(2+) exposed aortic rings. However, there was not significant difference in relaxation induced by SNP between Pb(2+) exposed and control group. The nitrite in the culture media of aortic rings cultured for 24h, measured with Griess method, was significantly decreased in the Pb(2+) exposed group. The expression of endothelial NOS (eNOS) and isoform NOS (iNOS) in the homogenate of aortic rings cultured for 24h was measured by Western blot. The expression of eNOS of the Pb(2+) exposed group was significantly upregulated compared with that of the control group. However, there was no significant difference in the expression of iNOS in control and Pb(2+) exposed group. In conclusion, Pb(2+) was able to directly affect the relaxation of rat aorta. This effect may have some relation with the lower level of NO in the media, though the expression of eNOS was upregulated.

A Drug Carrier for Sustained Zero-Order Release of Peptide Therapeutics.

Peptides have great potential as therapeutic agents, however, their clinic applications are severely hampered by their instability and short circulation half-life. Zero-order release carriers could not only extend the circulation lifetime of peptides, but also maintain the plasma drug level constant, and thus maximize their therapeutic efficacy and minimize their toxic effect. Here using PEGylated salmon calcitonin (PEG-sCT)/tannic acid (TA) film as an example, we demonstrated that hydrogen-bonded layer-by-layer films of a PEGylated peptide and a polyphenol could be a platform for zero-order peptide release. The films were fabricated under mild conditions. The second component, TA, is a natural product and presents potential therapeutic activities itself. Unlike common carriers, the new carrier releases the peptide via gradual disintegration of the film because of its dynamic nature. The release of PEG-sCT follows a perfect zero-order kinetics without initial burst release. In addition the release rate could be tuned via external stimuli, such as pH and temperature. When implanted in rats, the films could remain the plasma level of PEG-sCT constant over an extended period. Accordingly, the serum calcium level was reduced and maintained constant over the same period, suggesting an improved therapeutic efficacy of the released drug.

A pH responsive complexation-based drug delivery system for oxaliplatin.

A responsive drug delivery system (DDS) for oxaliplatin (OX) has been designed with a view to overcoming several drawbacks associated with this anticancer agent, including fast degradation/deactivation in the blood stream, lack of tumor selectivity, and low bioavailability. The present approach is based on the direct host-guest encapsulation of OX by a pH-responsive receptor, carboxylatopillar[6]arene (CP6A). The binding affinities of CP6A for OX were found to be pH-sensitive at biologically relevant pH. For example, the association constant (Ka) at pH 7.4 [Ka = (1.02 ± 0.05) × 104 M-1] is 24 times larger than that at pH 5.4 [Ka = (4.21 ± 0.06) × 102 M-1]. Encapsulation of OX within the CP6A cavity did not affect its in vitro cytotoxicity as inferred from comparison studies carried out in several cancer cells (e.g., the HepG-2, MCF-7, and A549 cell lines). On the other hand, complexation by CP6A serves to increase the inherent stability of OX in plasma by 2.8-fold over a 24 h incubation period. The formation of a CP6A⊃OX host-guest complex served to enhance in a statistically significant way the ability of OX to inhibit the regrowth of sarcoma 180 (S180) tumors in Kunming (KM) mice xenografts. The improved anticancer activity observed in vivo for CP6A⊃OX is attributed to the combined effects of enhanced stability of the host-guest complex and the pH-responsive release of OX. Specifically, it is proposed that OX is protected as the result of complex formation and then released effectively in the acidic tumor environment.

A simple method for the formalin fixation of lungs in toxicological pathology studies.

Optimized lung preparation for detailed structural evaluation is required to improve consistency in preclinical safety evaluation, differences of opinion exist among regulatory agency personnel regarding the optimal methods for routine formalin fixation of lungs from rodent toxicology studies. The simple tracheal ligation fixation method emphasizes tracheal ligation before opening the thorax instead of attempting to re-inflate after lung collapse when opening the thorax. Photomicrographs of this method demonstrated an unprecedented ability to maintain the natural lung architecture, in contrast to the unavoidable changes in the alveolar environment by the intratracheal instillation and vascular perfusion methods. In addition, a comparison of fixation methods on lung morphology in a rodent model of LPS-induced acute lung injury demonstrated that the tracheal ligation fixation method may provide a standard approach for morphometry. Additionally, a TUNEL assay was used to determine the degree of autolysis, which revealed that the autolysis was insignificant in the central areas of each lobe of the lung compared to the lung periphery by tracheal ligation fixation. In conclusion, our novel modified method, which avoids the disadvantages of generating artifacts, fulfills the requirement of preserving the clear, natural morphology of the lung making it suitable and worthy of recommendation for toxicological studies in a good laboratory practice (GLP) lab.

ResSeq: Enhancing Short-Read Sequencing Alignment By Rescuing Error-Containing Reads.

UNLABELLED: Next-generation short-read sequencing is widely utilized in genomic studies. Biological applications require an alignment step to map sequencing reads to the reference genome, before acquiring expected genomic information. This requirement makes alignment accuracy a key factor for effective biological interpretation. Normally, when accounting for measurement errors and single nucleotide polymorphisms, short read mappings with a few mismatches are generally considered acceptable. However, to further improve the efficiency of short-read sequencing alignment, we propose a method to retrieve additional reliably aligned reads (reads with more than a pre-defined number of mismatches), using a Bayesian-based approach. In this method, we first retrieve the sequence context around the mismatched nucleotides within the already aligned reads; these loci contain the genomic features where sequencing errors occur. Then, using the derived pattern, we evaluate the remaining (typically discarded) reads with more than the allowed number of mismatches, and calculate a score that represents the probability that a specific alignment is correct. This strategy allows the extraction of more reliably aligned reads, therefore improving alignment sensitivity. IMPLEMENTATION: The source code of our tool, ResSeq, can be downloaded from: https://github.com/hrbeubiocenter/Resseq.

Subchronic toxicological study of two artemisinin derivatives in dogs.

The objective of our study was to profile and compare the systematic changes between orally administered artesunate and intramuscularly injected artemether at a low dose over a 3-month period (92 consecutive days) in dogs. Intramuscular administration of 6 mg kg-1 artemether induced a decreased red blood cell (RBC) count (anemia), concurrent extramedullary hematopoiesis in the spleen and inhibition of erythropoiesis in the bone marrow. We also observed a prolonged QT interval and neuropathic changes in the central nervous system, which demonstrated the cortex and motor neuron vulnerability, but no behavioral changes. Following treatment with artesunate, we observed a decreased heart rate, which was most likely due to cardiac conduction system damage, as well as a deceased RBC count, extramedullary hematopoiesis in the spleen and inhibition of erythropoiesis in the bone marrow. However, in contrast to treatment with artemether, neurotoxicity was not observed following treatment with artesunate. In addition, ultra-structural examination by transmission electron microscopy showed mitochondrial damage following treatment with artesunate. These findings demonstrated the spectrum of toxic changes that result upon treatment with artesunate and artemether and show that the prolonged administration of low doses of these derivatives result in diverse toxicity profiles.

Global gene expression profiles of MT knockout and wild-type mice in the condition of doxorubicin-induced cardiomyopathy.

Increasing evidence from in vivo and in vitro studies has indicated that MT exerts protective effects against DOX-induced cardiotoxicity; however the underlying precise mechanisms still remain an enigma. Therefore, the present study was designed using MT knockout mice in concert with genomic approaches to explore the possible molecular and cellular mechanisms in terms of the genetic network changes. MT-I/II null (MT⁻/⁻) mice and corresponding wild-type mice (MT+/+) were administrated with a single dose of DOX (15 mg/kg, i.p.) or equal volume of saline. Animals were sacrificed on the 4th day after DOX administration and samples were collected for further analyses. Global gene expression profiles of cardiac mRNA from two genotype mice revealed that 381 characteristically MT-responsive genes were identified between MT+/+ mice and MT⁻/⁻ mice in response to DOX, including fos, ucp3, car3, atf3, map3k6, etc. Functional analysis implied MAPK signaling pathway, p53 signaling pathway, Jak-STAT signaling pathway, PPAR signaling pathway, Wnt signaling pathway, etc. might be involved to mediate the protection of DOX cardiomyopathy by MT. Results from the present study not only validated the previously reported possible mechanisms of MT protection against DOX toxicity, but also provided new clues into the molecular mechanisms involved in this process.

Apoptosis in microencapsulated juvenile rabbit chondrocytes induced by ofloxacin: role played by beta(1)-integrin receptor.

Quinolone(s) (QNs) is widely used in infection therapy due to its good antimicrobial characteristics. However, QNs-induced arthropathy of immature animals has led to restrictions on the therapeutic use of these antimicrobial agents. The exact mechanism(s) of QNs-induced chondrotoxicity remain unknown. In the present study, we investigated the possible mechanism of ofloxacin (one typical QNs)-induced injuries of chondrocytes. Juvenile rabbit joint chondrocytes cultured in alginate microspheres were incubated with ofloxacin at concentrations of 0, 2, 5, 10, 20, and 40 microg/ml for up to 96 h. Concentration of 10 microg/ml ofloxacin induced apoptosis of chondrocyte with visible apoptotic signs, including degradation of poly(ADP-ribose) polymerase, caspase-3 activation, and DNA ladder formation. Furthermore, extracellular signal-regulated kinase 1/2 (phospho-ERK1/2) and growth factor receptor-bound protein 2 (Grb2) were significantly reduced, and similar changes were also observed in the beta(1)-integrin receptor as assessed by immunoblotting. However, the mRNA level of beta(1)-integrin obtained from reverse transcription-polymerase chain reaction remained unchanged. Results of beta(1)-integrin immunoprecipitation have also shown that beta(1)-integrin did not interact with activated intracellular signaling proteins. In addition, ofloxacin did not induce apoptosis and decrease beta(1)-integrin expression in chondrocytes supplemented with Mg(2+), and the ofloxacin-induced apoptosis was caspase-8-dependent, inhibition of which did not affect the expression mode of phospho-ERK1/2 and beta(1)-integrin. Our results demonstrate that ofloxacin affects beta(1)-integrin receptor functions and the ERK mitogen-activated protein kinase signaling pathway, causing caspase-8-dependent apoptosis after exposure of 48 h.