Self-gated, dynamic contrast-enhanced magnetic resonance imaging with compressed-sensing reconstruction for evaluating endothelial permeability in the aortic root of atherosclerotic mice

High-risk atherosclerotic plaques are characterized by active inflammation and abundant leaky microvessels. We present a self-gated, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) acquisition with compressed sensing reconstruction and apply it to assess longitudinal changes in endothelial permeability in the aortic root of Apoe-/- atherosclerotic mice during natural disease progression. Twenty-four, 8-week-old, female Apoe-/- mice were divided into four groups (n = 6 each) and imaged with self-gated DCE-MRI at 4, 8, 12, and 16 weeks after high-fat diet initiation, and then euthanized for CD68 immunohistochemistry for macrophages. Eight additional mice were kept on a high-fat diet and imaged longitudinally at the same time points. Aortic-root pseudo-concentration curves were analyzed using a validated piecewise linear model. Contrast agent wash-in and washout slopes (b1 and b2 ) were measured as surrogates of aortic root endothelial permeability and compared with macrophage density by immunohistochemistry. b2 , indicating contrast agent washout, was significantly higher in mice kept on an high-fat diet for longer periods of time (p = 0.03). Group comparison revealed significant differences between mice on a high-fat diet for 4 versus 16 weeks (p = 0.03). Macrophage density also significantly increased with diet duration (p = 0.009). Spearman correlation between b2 from DCE-MRI and macrophage density indicated a weak relationship between the two parameters (r = 0.28, p = 0.20). Validated piecewise linear modeling of the DCE-MRI data showed that the aortic root contrast agent washout rate is significantly different during disease progression. Further development of this technique from a single-slice to a 3D acquisition may enable better investigation of the relationship between in vivo imaging of endothelial permeability and atherosclerotic plaques' genetic, molecular, and cellular makeup in this important model of disease.

Modeling Spitz melanoma in zebrafish using sequential mutagenesis

Spitz neoplasms are a diverse group of molecularly and histologically defined melanocytic tumors with varying biologic potentials. The precise classification of Spitz neoplasms can be challenging. Recent studies have revealed recurrent fusions involving multiple kinases in a large proportion of Spitz tumors. In this study, we generated a transgenic zebrafish model of Spitz melanoma using a previously identified ZCCHC8-ROS1 fusion gene. Animals developed grossly apparent melanocytic proliferations as early as 3 weeks of age and overt melanoma as early as 5 weeks. By 7 weeks, ZCCHC8-ROS1 induced a histologic spectrum of neoplasms ranging from hyperpigmented patches to melanoma. Given the swift onset of these tumors during development, we extended this approach into adult fish using a recently described electroporation technique. Tissue-specific expression of ZCCHC8-ROS1 in adults led to melanocyte expansion without overt progression to melanoma. Subsequent electroporation with tissue-specific CRISPR, targeting only tp53 was sufficient to induce transformation to melanoma. Our model exhibits the use of sequential mutagenesis in the adult zebrafish, and demonstrates that ZCCHC8-ROS1 induces a spectrum of melanocytic lesions that closely mimics human Spitz neoplasms.

Summary: We describe the first animal model of Spitz neoplasms and demonstrate its use for modeling sequential mutagenesis and its potential for studying melanocyte development in vivo.

2379Endothelial cell derived extracellular vesicles mediate immune cell deployment from the spleen and transcriptional programming following acute myocardial infarction

Background

Acute myocardial infarction (AMI) induces transcriptional activation of monocyte en route to the injured myocardium, possibly through interactions involving plasma liberated extracellular vesicles (EVs), which are enriched for proteins and microRNAs (miRNAs) post-AMI. Neutrophils are the first immune cells to arrive at sites of injury and mediate further damage to the ischaemic myocardium. Here, we describe neutrophil-deployment from the spleen in AMI and by endothelial cell (EC) derived-EVs.

Methods

Patients presenting AMI provided informed consent as part of the Oxford Acute Myocardial Infarction Study (OxAMI). Plasma EV were isolated by differential ultra-centrifugation (120,000g, 2 hours) followed by washing and characterised for: morphology using transmission electron microscopy (TEM), size and concentration profiling by Nanoparticle Tracking Analysis, EV markers (TSG101, ALIX, CD9, HSP70) by western blot, and miRNAs by RT-qPCR. Mouse and human EC were used in vitro to derive EC-EV under control conditions or after inflammatory stimulation with tumour necrosis factor-alpha (TNF-α) (10ng/mL) and from CRISPR-edited miRNA-126 knock-out ECs. EC-EVs were tail vein injected into wild-type mice or exposed to primary human peripheral blood neutrophils in vitro.

Results

Patients presenting with AMI (N=15) have significantly more plasma EV at time of injury vs a 6-month follow-up measurement (2.2-fold more, P=0.008). Plasma EVs at the time of AMI presentation correlate significantly with the extent of ischaemic injury (R=0.046, P=0.006) and plasma neutrophils (R=0.37, P=0.017). Experimental AMI in wild-type mice induced a significant increase in peripheral blood neutrophils and a simultaneous reduction in splenic-neutrophils, suggesting splenic-neutrophil deployment (P=0.004). Human plasma EV are enriched for vascular cell adhesion molecule-1 (VCAM-1) and EC-associated miR-126 post-AMI (Akbar et al 2017). miRNA-126-mRNA targets are significantly over represented when compared to neutrophil Gene Ontology terms for: degranulation (P<0.001), activation (P<0.001), chemotaxis (P=0.008) and migration (P=0.008). Human and mouse EC release more EV after inflammatory stimulation and show enrichment for miRNA-126. CRISPR-edited miRNA-126 deficient human EC express more VCAM-1 (P<0.001) and release more EC-EVs (P<0.001). EC-EV exposure to primary human neutrophils alters inflammatory gene expression (IL-6 (P<0.05), CCL7 (P<0.001) and CCL18 (P<0.001)). EC-EV tail vein injected into wild-type mice mobilise splenic-neutrophils to peripheral blood (P<0.001).

Conclusions

Neutrophil deployment from the spleen is a novel finding in acute injury and interactions with EC-EV may mediate their splenic liberation and transcriptional programming following AMI, en route to the injured myocardium. The splenic neutrophil reserve may be a novel therapeutic target in AMI to modulate the inflammatory response before recruitment of cells to sites of injury.

Acknowledgement/Funding

British Heart Foundation Project Grant and Centre for Research Excellence Awards (RE/13/1/30181), Nuffield Benefaction for Medicine and ISSF

Ethyl Glucuronide as a Long-term Alcohol Biomarker in Fingernail and Hair. Matrix Comparison and Evaluation of Gender Bias

Aims

This work aimed to assess the performance of hair and fingernail ethyl glucuronide (EtG) measurement for use as a biomarker of alcohol consumption in persons with known drinking history across a range of drinking behaviours.

Methods

EtG concentrations were assessed from the hair and fingernails of 50 study participants. Alcohol consumption of the previous 90 days was assessed by participant interview using the alcohol timeline follow-back method. EtG concentration was determined using LC–MS-MS using a method which was validated and accredited to ISO/IEC 17025 standards.

Results

There was significant correlation between alcohol consumption and EtG concentrations found in hair and fingernail samples across the study group (n = 50). From participants testing positive for EtG (male n = 14, female n = 13) no significant difference was found between male and female EtG levels in either hair or fingernails. Across all participants there was no significant difference in hair or fingernail EtG concentration between male (n = 23) and females (n = 27).

Conclusions

Our results support the use of EtG to indicate alcohol consumption over the previous 90 days, or ~3 months as is the normal practice in hair analysis. The results confirm that fingernails can be a useful alternative matrix where hair samples are not available.

A national prevalence study of pressure ulcers in French hospital inpatients

OBJECTIVE

To ascertain pressure ulcer prevalence rate in French hospitals.

METHOD

In 2004, a cross-sectional study was conducted in all French hospitals, except university hospitals. The National Pressure Ulcer Advisory Panel (NPUAP) staging was used. Data were collected using two self-administered questionnaires.

RESULTS

A total of 37,307 inpatients in 1170 wards in 1149 hospitals were assessed, representing a response rate of 93.5%. Their mean age was 72.3 years and 62% were females. In all, 3314 patients had at least one pressure ulcer, giving a prevalence rate of 8.9%. A total of 4991 pressure ulcers were recorded; 64% of the patients had only one pressure ulcer. Fifty-five per cent of the patients had at least two concomitant diseases. When patients with only one ulcer were assessed, the most common locations were the heels (53%) and sacrum (29%). Heel pressure ulcers were more common in patients with obliterative arterial disease, and sacral pressure ulcers were more frequent in incontinent (urine, faecal and double incontinence) patients. Patients with multiple pressure ulcers had more severe lesions.

CONCLUSION

These results indicate that the prevalence of pressure ulcers in French hospital inpatients has remained stable since the last prevalence study undertaken 10 years before, when the rate was 8.9%. Such studies should be encouraged in all health-care settings as a means of improving the care provided.

Zoledronate inhibits proliferation and induces apoptosis of imatinib-resistant chronic myeloid leukaemia cells

Although imatinib mesylate has revolutionized the treatment of chronic myeloid leukaemia (CML), resistance to the drug, manifesting as relapse after an initial response or persistence of disease, remains a therapeutic challenge. In order to overcome this, alternative or additional targeting of signaling pathways downstream of Bcr-Abl may provide the best option for improving clinical response. Bisphosphonates, such as zoledronate, have been shown to inhibit the oncogenicity of Ras, an important downstream effector of Bcr-Abl. In this study, we show that zoledronate is equally effective in inhibiting the proliferation and clonogenicity of both imatinib-sensitive and -resistant CML cells, regardless of their mechanism of resistance. This is achieved by the induction of S-phase cell cycle arrest and apoptosis, through the inhibition of prenylation of Ras and Ras-related proteins by zoledronate. The combination of imatinib and zoledronate also augmented the activity of either drug alone and this occurred in imatinib-resistant CML cells as well. Since zoledronate is already available for clinical use, these results suggest that it may be an effective addition to the armamentarium of drugs for the treatment of CML.

Canine large granular lymphocyte leukemia and its derived cell line produce infectious retroviral particles

We describe a case of large granular lymphocyte (LGL) leukemia in a dog that we followed over a period of 2 years. Analysis of a hematological profile revealed lymphocytosis (19,500 lymphocytes per microliter; reference values, 1,000-4,800 lymphocytes per microliter), with a majority of LGL on the blood smear. LGL is defined as a lymphoid subset comprising 10% of peripheral blood mononuclear cells and corresponding to either CD3- CD8- NK cells or CD3+ CD8+ T cells. The cells are characterized by abundant basophilic cytoplasm containing distinct granules of variable size and number. The characteristic phenotype of our leukemic LGL is of a cytotoxic T cell, CD3+ and CD8+. A new cell line, DLC 02, was established from the peripheral lymphocytes of the leukemic dog. Particles with type C retroviral morphology were found in ultrathin sections of DLC 02 cell pellets. These particles were found to have a sucrose gradient density of 1.17 g/liter and a reverse transcriptase activity with an Mn2+ preference, suggesting that they correspond to a mammalian type C oncovirus.

Characterization of a canine long-term T cell line (DLC 01) established from a dog with Sézary syndrome and producing retroviral particles

The canine DLC 01 cell line derives from a lymph node of a dog with Sézary syndrome. The DLC 01 cell phenotype is CD4-, CD8+, CD45+, DQ+, similar to that of original cells after treatment with dimethylsulfoxide or phorbol myristate. Canine cutaneous T cell lymphoma are usually CD4-, CD8+ in contrast to their human counterparts which are CD4+, CD8-. Therefore, the DLC 01 cell line appears to be a unique model to study the mechanism of all surface molecule expression in vitro. Viral particles with retrovirus type-C morphology were found in ultrathin sections of DLC 01 cell pellets. Retroviral particles are spontaneously produced after the 50th cell passage or after induction with 0.5% dimethylsulfoxide. This is the first description of a dog lymphoid cell line spontaneously growing and producing a retrovirus. It was found to share several features in common with feline and murine leukemia viruses.

Aminopyrimidines with high affinity for both serotonin and dopamine receptors

A series of [4-[2(4-arylpiperazin-1-yl)alkyl]cyclohexyl]pyrimidin-2-ylamine s was prepared and found to have receptor binding affinity for D2 and D3 dopamine (DA) receptors and serotonin 5-HT1A receptors. The structural contributions to D2/D3 and 5-HT1A receptor binding of the aminopyrimidine, cycloalkyl, and phenylpiperazine portions of the molecule were examined. From these studies compounds 14, 39, 42, 43, having potent affinity for both DA D2 and 5-HT1A receptors, were evaluated for intrinsic activity at these receptors, in vitro and in vivo. Compound 14 (PD 158771) had a profile indicative of partial agonist activity at both D2 and 5-HT1A receptors causing partially decreased synthesis of the neurotransmitters DA and 5-HT and their metabolites. This compound has a profile in behavioral tests that is predictive of antipsychotic activity, suggesting that mixed partial agonists such as 14 may have utility as antipsychotic agents with increased efficacy and decreased side effects.

TM domain swapping of murine leukemia virus and human T-cell leukemia virus envelopes confers different infectious abilities despite similar incorporation into virions

We investigated the influence of transmembrane protein (TM) domains on incorporation of retroviral envelopes into virions and on infectivity. We introduced complete, truncated, or chimeric Friend murine leukemia virus (F-MuLV) and human T-cell leukemia virus type 1 (HTLV-1) envelopes into an MuLV particle-producing complementation cell line. As shown previously for HTLV-1 envelopes containing extracellular domains of F-MuLV TM (C. Denesvre, P. Sonigo, A. Corbin, H. Ellerbrok, and M. Sitbon, J. Virol. 69:4149-4157, 1995), reverse chimeric F-MuLV envelopes containing the extracellular domain of HTLV-1 TM were not processed. In contrast, a chimeric MuLV envelope containing the entire HTLV membrane-spanning and cytoplasmic domains (FHTMi) was efficiently processed, fusogenic as tested in a cell-to-cell assay, and efficiently incorporated into MuLV particles. However, these MuLV particles bearing FHTMi envelope proteins could not infect mouse or rat cells which are susceptible to wild-type F-MuLV. Therefore, envelopes which are readily fusogenic in cell-to-cell assays and also efficiently incorporated into virions may not necessarily confer virus-to-cell fusogenicity. HTLV envelopes, whether parental, chimeric (containing the MuLV cytoplasmic tail) or with a truncated cytoplasmic domain, were incorporated into MuLV particles with equal efficiencies, indicating that the cytoplasmic tails of these envelopes did not determine their incorporation into virions. In contrast to FHTMi envelope, HTLV-1 envelopes with F-MuLV membrane-spanning and cytoplasmic domains, as well as wild-type HTLV-1 envelopes, conferred virion infectivity. These results help to define requirements for envelope incorporation into retroviral particles and their cell-free infectivity.

Functions of the 5' leader of murine leukemia virus genomic RNA in virion structure, viral replication and pathogenesis, and MLV-derived vectors

Retroviruses are a family of widespread small animal viruses that can cause a variety of neoplastic and immunosuppressive diseases. Murine leukemia viruses (MuLV) have been used as model systems to investigate virion and genomic RNA structure, viral replication and variability, and pathogenesis. Detailed knowledge of the genetic structure of MuLV and of the viral life cycle has led to the development of MuLV-derived retroviral vectors for gene transfer with potential applications in human gene therapy. In this review we have summarized the properties and functions of the 5' domain, called the leader, of MuLV genomic RNA. The 5' leader is formed of small interspersed and superimposed genetic elements involved in every step of the viral life cycle. In addition, the 3' domain of the leader encodes the N-terminal part of glycosylated forms of the GAG polyprotein, also named Gross cell surface antigen (GCSA or glycoGAG) which is essential for full spreading and pathogenic abilities of the virus in the animal. Therefore, the 5' leader of MuLV genomic RNA appears to be a very attractive model to study structure-function relationships of a small and multifunctional genetic domain in vitro, in cell culture and in the animal.

Influence of transmembrane domains on the fusogenic abilities of human and murine leukemia retrovirus envelopes

The envelopes of two highly divergent oncoviruses, human T-cell leukemia virus type 1 (HTLV-1) and Friend murine leukemia virus (F-MuLV), have distinct patterns of cellular receptor recognition, fusion, and syncytium formation. To analyze the influence of the transmembrane envelope subunit (TM) on fusogenic properties, we substituted either the entire TM or distinct domains from F-MuLV for the corresponding domains in the HTLV-1 envelope. Parental, chimeric, and truncated envelopes cloned into a eukaryotic expression vector were monitored for fusogenic potential in human, rat, and murine indicator cell lines by using a quantitative assay. This highly sensitive assay allowed us to assess the fusogenic properties and syncytium-forming abilities of the HTLV-1 envelope in murine NIH 3T3 cells. All chimeric envelopes containing extracellular sequences of the F-MuLV TM were blocked in their maturation process. Although deletions of the HTLV-1 cytoplasmic domain, alone and in combination with the membrane-spanning domain, did not prevent envelope cell surface expression, they impaired and suppressed fusogenic properties, respectively. In contrast, envelopes carrying substitutions of membrane-spanning and cytoplasmic domains were highly fusogenic. Our results indicate that these two domains in F-MuLV and HTLV-1 constitute structural entities with similar fusogenic properties. However, in the absence of a cytoplasmic domain, the F-MuLV membrane-spanning domain appeared to confer weaker fusogenic properties than the HTLV-1 membrane-spanning domain.

Different abilities of Friend murine leukemia virus (MuLV) and Moloney MuLV to induce promonocytic leukemia are due to determinants in both psi-gag-PR and env regions

Moloney murine leukemia virus (M-MuLV) is capable of inducing promonocytic leukemia in 50% of adult BALB/c mice that have received peritoneal injections of pristane, but Friend MuLV strain 57 (F-MuLV) is nonleukemogenic under similar conditions. It was shown earlier that these differences could not be mapped to the U3 region of the virus long terminal repeat, indicating the probable influence of structural genes and/or R-U5 sequences. In this study, reciprocal chimeras containing exchanged structural genes and R-U5 sequences from these two closely related viruses were analyzed for differences in ability to induce disease. Results showed that two regions of F-MuLV, psi-gag-PR and env, when substituted for those of M-MuLV were dramatically disease attenuating. The 5'-most region, which is widely distributed, overlaps with the 5' end of the env intron and includes the RNA packaging region, psi, the entire gag coding region, and the viral protease coding region (PR) of pol. It was also found that reciprocal constructs having substitutions of both of these regions of M-MuLV in an F-MuLV background allowed full reestablishment of promonocytic leukemia. These leukemias were positive for c-myb rearrangements which are characteristic of M-MuLV-induced promonocytic leukemias. Neither region alone, however, was sufficient to produce disease with a greater incidence than 13%. Further studies demonstrated that the inability of viruses with psi, gag, PR, or env sequences from F-MuLV to induce leukemia in this model system was not due to their inability to replicate in hematopoietic tissue, to integrate into the c-myb locus early on after infection in vivo, or to express gag-myb mRNA characteristic of M-MuLV-induced preleukemic cells and acute leukemia.

The envelopes of two ecotropic murine leukemia viruses display distinct efficiencies in retroviral vaccination by interference

In cell cultures infected with a retrovirus, the expression of the viral envelope interferes with superinfection by retroviruses which recognize the same receptor. We have previously demonstrated that vaccination of susceptible strains of mice (of the Mus musculus species) with the attenuated ecotropic Friend murine leukemia virus (F-MuLV) B3 efficiently protects against the early hemolytic anemia and the erythroleukemia induced by a challenge with the virulent F-MuLV 57 through a similar in vivo mechanism of interference to superinfection (A. Corbin and M. Sitbon, J. Virol. 67, 5146-5152, 1993). Vaccination with the heterologous ecotropic Moloney-MuLV (M-MuLV) efficiently protects against the early hemolytic anemia but has a weak protective effect on the F-MuLV 57-induced erythroleukemia. Furthermore, vaccination with the attenuated F-MuLV B3 had only a transient protective effect on M-MuLV-induced thymomas. These different efficiencies of F- and M-MuLV to confer protection in this model of vaccination by interference were mostly due to envelope sequences, indicative of distinct in vivo interference properties of the two ecotropic envelopes.

A nonstructural gag-encoded glycoprotein precursor is necessary for efficient spreading and pathogenesis of murine leukemia viruses

In addition to the Gag-Pol and Env precursors whose translation initiates at AUG codons, murine, feline, and simian type C oncoviruses also express glycosylated Gag-Pol precursors (glycoGag), glycoGag translation is initiated at CUG codons located upstream of the Gag AUG initiation codon. In contrast to Gag, glycoGag is translocated into the endoplasmic reticulum and is absent from virions. Since glycoGag has been described to be dispensable ex vivo, we investigated the in vivo effects of a glycoGag- mutation in the Friend murine leukemia virus (F-MuLV). F-MuLV induces severe early hemolytic anemia and subsequent erythroleukemia within 2 months after inoculation of newborn mice. We obtained a glycoGag- F-MuLV, strain H5, by inserting an octanucleotide linker downstream of the CUG codon leading to the reading of a stop codon in all reading frames upstream of the Gag AUG. F-MuLV H5 did not induce severe early hemolytic anemia, and latency of erythroleukemia was significantly increased most likely because of an approximately 1-week delay in the in vivo spreading. Accordingly, induction of recombinant polytropic viruses was also significantly delayed. Close examination of ex vivo spreading kinetics also showed a slower dissemination of F-MuLV H5. Western blot (immunoblot) performed after inoculation of newborn mice with this glycoGag- virus indicated the emergence of new glycoGag+ viruses. PCR analyses with F-MuLV-specific primers demonstrated in vivo pseudoreversions restoring the glycoGag reading frame. Our results demonstrated that glycoGag expression is positively selected and essential for full spreading and pathogenic abilities.

Sequences responsible for the distinctive hemolytic potentials of Friend and Moloney murine leukemia viruses are dispersed but confined to the psi-gag-PR region

Friend and Moloney murine leukemia viruses (F- and M-MuLV) induce distinct diseases in hematopoietic tissues following inoculation of newborn mice of susceptible strains. F-MuLV induces erythroleukemia preceded by severe early hemolytic anemia; M-MuLV induces thymomas and only very mild hemolysis. The major viral determinant of severe early hemolytic anemia residues in the env gene, but sequences located outside this gene can modulate this effect. By means of genetic chimeras of F- and M-MuLV, we have found that although they are confined to the 5' portion of the env gene intron, sequences that determine the distinctive hemolytic potentials of F- and M-MuLV are widely distributed over a region spanning the RNA encapsidation domain, the gag gene, and the portion of the pol gene encoding the viral protease. Within this large region, two fragments of M-MuLV, a 1.3-kb region encoding the matrix, pp12, and capsid proteins and a 0.8-kb region encoding the nucleocapsid and the viral protease, were capable, individually, of partially attenuating the capacity of F-MuLV for induction of severe early hemolytic anemia. In association, these two fragments conferred complete attenuation. Moreover, a second pair of adjacent fragments within this large region appeared to behave cooperatively to confer complete attenuation; a 0.36-kb region roughly corresponding to the encapsidation domain, although not detectably altering hemolytic potential on its own, deepened the attenuation conferred by the adjacent 1.3-kb region. Whether capable of inducing severe early hemolytic anemia or not and despite different efficiencies of induction of recombinant polytropic viruses, all chimeric viruses retained the erythroleukemogenicity of the F-MuLV parent.

Protection against retroviral diseases after vaccination is conferred by interference to superinfection with attenuated murine leukemia viruses

Cell cultures expressing a retroviral envelope are relatively resistant to superinfection by retroviruses which bear envelopes using the same receptor. We tested whether this phenomenon, known as interference to superinfection, might confer protection against retroviral diseases. Newborn mice first inoculated with the attenuated strain B3 of Friend murine leukemia virus (F-MuLV) were protected against severe early hemolytic anemia and nonacute anemiant erythroleukemia induced by the virulent strain 57 of F-MuLV. Vaccinated animals were also protected as adults against acute polycythemic erythroleukemia induced upon inoculation with the viral complex containing the defective spleen focus-forming virus and F-MuLV 57 as helper virus. Animals were inoculated as newborns, which is known to induce immune tolerance in mice, and the rapid kinetics of protection, incompatible with the delay necessary for the immune response to develop, indicated that protection was not due to an immune mechanism but rather was due to the rapid and long-lasting phenomenon of interference. This result was confirmed by combining parental and envelope chimeric MuLV from different interference groups as vaccinal and challenge viruses. Although efficient protection could be provided by vaccination by interference, we observed that attenuated replication-competent retroviruses from heterologous interference groups might exert deleterious synergistic effects.

Pharmacological characterization of PD 118717, a putative piperazinyl benzopyranone dopamine autoreceptor agonist

PD 118717 (7-[3-[4-(2-pyrimidinyl)-1-piperazinyl]-propoxy]-2H-1- benzopyran-2-one sulfate) proved to be a dopamine (DA) D-2 autoreceptor agonist in biochemical and electrophysiological studies in rats and to exhibit an antipsychotic-like profile in behavioral tests in rodents and monkeys. In vitro binding studies indicated that PD 118717 bound selectively to DA D-2 vs. D-1 receptors and exhibited agonist binding properties (biphasic inhibitory curves and GTP shift) similar to DA. It also had significant affinity for serotonin-(5-HT)1A but not 5-HT1B and 5-HT2 receptors. PD 118717 was active in antagonizing the tau-butyrolactone-induced accumulation of dopa in rat striatum and mesolimbic regions. PD 118717 also depressed the firing of DA neurons in substantia nigra pars compacta of rats. In both of the latter tests the effects of PD 118717 were reversed by haloperidol. PD 118717 decreased brain DA metabolism, decreased DA utilization, decreased accumulation of dopa after inhibition of L-aromatic amino acid decarboxylase, stimulated serum corticosterone and inhibited stimulated serum prolactin levels. PD 118717 did not alter striatal acetylcholine levels; nor did it induce locomotor stimulation or stereotypy in normal animals, suggesting a lack of postsynaptic DA stimulation of normosensitive DA receptors. In tests designed to reveal even weak postsynaptic DA agonist effects, PD 118717 stimulated locomotor activity in 6-hydroxydopamine-lesioned animals and relatively higher doses induced a low degree of stereotyped behavior when combined with the DA D-1 agonist SKF 38393. PD 118717 decreased the accumulation of 5-hydroxytryptophan in brain, an effect probably due to an agonist action at 5-HT1A receptors. PD 118717 decreased spontaneous locomotor activity in rodents, antagonized amphetamine-stimulated hyperactivity in mice and inhibited Sidman avoidance in monkeys, effects seen with antipsychotic agents. Unlike DA antagonist antipsychotics, PD 118717 did not induce extrapyramidal dysfunction in monkeys. PD 118717 displayed behavioral activity after p.o. dosing and its effects did not show tolerance on repeated dosing. In conclusion, PD 118717 has the profile of a DA autoreceptor agonist in neurochemical and neurophysiological tests and produces effects suggestive of antipsychotic efficacy without neurological side effect liability in preclinical behavioral tests.

The relevance of the pharmacologic properties of a progestational agent to its clinical effects as a combination oral contraceptive

Levonorgestrel (LNg) is known for its marked progestational/contraceptive activity. As shown in animal experiments, however, high doses of LNg are required to elicit an androgenic response; in contrast, considerably lower doses of LNg are required for antiovulatory (contraceptive) action. Thus, a large dose separation exists between androgenic and contraceptive activity. When LNg is combined with an estrogen, as in the contraceptive formulations, the androgenic response is attenuated or negated. The results of recent clinical trials have demonstrated that the androgenic activity of LNg is not expressed at contraceptive doses, particularly when LNg is combined with ethinyl estradiol (EE), as in the low-dose monophasic/triphasic formulations (monophasic [Nordette]: 150 mcg LNg/30 mcg EE; triphasic [Triphasil/Trinordiol]: six days, 50 mcg LNg/30 mcg EE; five days, 75 mcg LNg/40 mcg EE; ten days, 125 mcg LNg/30 mcg EE). Clinical evidence from several trials confirms that sex hormone-binding globulin levels are increased, plasma androgen levels are decreased, and acne is markedly improved with the use of Triphasil and Nordette, suggesting a non-androgenic profile.

Cyclic response of hypophysectomized rats to ovulation induced by LHRH agonist: mediation by prostaglandins

Further confirmation that the LHRH/LHRH agonist-induced ovulation in the hypophysectomized (hypx) rat is due to a direct ovarian effect and not mediated by LH release from residual pituitary tissue or other CNS sites is provided by the persistence of this effect despite concomitant median eminence lesion or passive immunization to LH. Adrenalectomy did not affect the ovulatory activity of the LHRH agonist, D-Trp6-N alpha MeLeu7-DesGly10-Pro9-NHEt-LHRH (Wy-40,972), in the hypx rat. Prior administration of a potent LHRH antagonist blocked ovulation induced in hypx proestrous rats by Wy-40,972 but not by LH-S19. Ovulation can be induced by Wy-40,972 one day earlier (e.g. metestrus) in the intact rat than it can in the hypx rat. Results in the hypx metestrous rat indicate that the ovulatory responsiveness of the intact rat at this stage of the cycle may occur by complementary action of Wy-40,972-stimulated endogenous LH release and a direct ovarian effect of the agonist. Prostaglandins (PG) are involved in the ovulatory mechanism of Wy-40,972 in the hypx proestrous rat as evidenced by the dose-dependent inhibition of this effect by PG synthetase inhibitors, indomethacin and Fentiazac. Moreover, there were significant increases in ovarian concentrations of PGF2 alpha and PGE2-PGE1 in response to Wy-40,972 that could be prevented by indomethacin. However, exogenous administration of either of these PG's was not effective in inducing ovulation in the hypx rat.

Resistance of the mouse to the antifertility effects of LHRH agonists

In the mouse, the LH-releasing activity of the LHRH agonist, D-Trp6-N alpha-MeLeu7-DesGly10-Pro9-NHEt-LHRH (Wy-40,972), was established by its ability both to induce ovulation when administered at 1600 hours on the the second day of diestrus and to elevate serum LH in adult males. While Wy-40,972 was only slightly less active in terms of these and points than it was in the rat, the predictive and possibly causal association between LH-releasing and antifertility activity established for this LHRH analog in the rat could not be clearly identified in the mouse. A total daily dose of 1000 microgram Wy-40,972/mouse was required to completely inhibit pregnancy during days 1-7 of pregnancy and produced only partial inhibition during days 7-12. This dose represents, on a body weigh basis, 8250 times the 100 percent effective pregnancy-terminating dose for the rat during equivalent intervals. The resistance of the mouse to the antifertility activity of Wy-40,972 was found not to be restricted to this particular LHRH analog or to the reproductive state. Administration of another potent LHRH analog, D-Ala6-DesGly10-Pro9-NHEt-LHRH (Wy-18,481), to adult male mice at a dose of 100 microgram/mouse/day for up to 14 days had no inhibitory effect on the weights of the testes or sex accesory organs. This dose of Wy-18,481 is 7500 times that necessary for significant reduction of these reproductive organ weights in rats within 7 days of treatment. Investigation as to the nature of the mouse's apparently divergent response to the LHRH agonists may further elucidate the antifertility mechanism of such compounds in susceptible species.

From contraception to cancer: a review of the therapeutic applications of LHRH analogues as antitumor agents

LHRH and its analogues produce profound antireproductive effects in both sexes of a variety of animal species. Although the LHRH agonists induce gonadotropin release, gonadal steroid secretion, ovulation, and spermatogenesis as an expression of their traditional profertility pharmacologic profile, they paradoxically and characteristically cause predominant antifertility effects which have been extensively evaluated for potential contraceptive purposes. These agonists produce their antireproductive effects in both males and females by common mechanisms, ultimately resulting in disruption of pituitary-gonadal function, depression of steroidogenesis, and inhibition of target organs dependent on such gonadal support. Similar antireproductive effects have been observed with the LHRH antagonists which competitively inhibit LHRH-induced gonadotropin secretion resulting in reduced blood gonadal steroid levels. Use of the inhibitory properties has been extended to cancer therapy based on the ability of the LHRH analogues (particularly the agonists) to inhibit the growth of steroid-dependent (responsive) tumors (e.g., mammary, prostate) similar to that produced by gonadectomy and antisteroid treatments. The use of these peptides for selected hormone-sensitive tumors presents a novel pharmacotherapeutic application for this class of drug.

Luteinising hormone-releasing and anti-fertility properties of a glucagon-selective somatostatin analogue

The hypothalamic tetradecapeptide, somatostatin (SRIF), inhibits the secretion of growth hormone (GH) and numerous other hormones, including insulin and glucagon. Attempts to use SRIF as an adjunct in the treatment of diabetes mellitus met with limited success due to its short biological half-life and the undesirable diabetogenic activity of its insulin-lowering properties. Efforts at synthesis have yielded SRIF derivatives with prolonged GH-lowering activity which did not suppress glucagon or had equivalent insulin-inhibiting activity as well as several short-acting compounds with the appropriate glucagon specificity. A dodecapeptide analogue [des-Ala, Gly] His-D-Trp-SRIF (Wy-41, 747) has been identified that combines selective inhibition of GH and glucagon release with prolonged activity. However, in routine pharmacological tests chronic treatment of mature rats with Wy-41, 747 produced anti-reproductive effects resembling those described for luteinising hormone (LH)-releasing hormone (RH) and its agonists. We report here that Wy-41, 747, unlike SRIF and other of its analogues tested, releases LH, induces ovulation and inhibits pregnancy when administered before or after implantation; these properties are traditionally associated with the separate LH-releasing class of peptides.

Peptide contraception: antifertility properties of LH-RH analogues

A prototype LH-RH antagonist dampened the proestrous gonadotropin surge and blocked ovulation but had no effect on pregnant animals. In contrast, LH-RH and two highly potent LH-RH agonists terminated pregnancy when administrated prior to or following implantation. This contragestational effect, as well as other antireproductive properties of the agonists, coupled with the reversibility of their effects, strongly suggest that peptides may provide a new basis for contraception.

Agonist (ovulation induction) and post-coital contraceptive properties of [D-Ala6] and [D-Trp6]-LHRH series

Seven derivatives of LH-RH, representing the [D-Ala6] or [D-Trp6] series, with or without a Fujino modification, were evaluated for ovulation-inducing (agonist and post-coital contraceptive activity in rats. Six of these analogues had a high degree of agonist and pregnancy-terminating potency. In general, several modifications can result in a particular series of composite molecules that possess a biologic potency greater than each of its predecessors; this correlation of structure with activity was more consistent in the [D-Ala6]-series than in the [D-Trp6]-series. The relationship between structural modifications, resistance to enzyme degradation (based on literature reports) and increased biologic potency is discussed.

Effect of an LH-RH antagonist on reproductive status of immature female rats

Administration of the LH-RH antagonist, D-Phe2-D-Ala6-LH-RH (Wy-18, 185) to immature female rats from days 25--35 of age was without significant effect on day of vaginal opening (puberal onset), weights of the ovaries, uteri and anterior pituitary, and on ovarian histology on autopsy day 39.

Postcoital contraceptive effects of agonist analogs of luteinizing hormone-releasing hormone

Various analogs of synthetic hypothalamic luteinizing hormone-releasing hormone (LH-RH) were evaluated for agonistic (ovulation-inducing), postcoital contraceptive, and direct uterotrophic activities. All analogs showing agonistic activity also possessed the ability to terminate pregnancy, as did LH-RH; there appeared to be a direct relationship between agonistic and postcoital potency and activity. The highly potent and active LH-RH agonist, D-[Ala]6-des-[Gly]10-pro9-ethylamide-LH-RH, proved to be the most potent and active postcoital preimplantational and postimplantational antifertility agent. In contrast to LH-RH, none of the analogs tested in the hypophysectomized animal produced a uterotrophic effect, revealing a selective extrapituitary effect of the parent hormone. The collective data demonstrate that peptides derived from LH-RH and bearing agonistic properties can terminate pregnancy postcoitally, via disruption of the pituitary-ovarian reproductive complex. Possible mechanisms are discussed, and the use of members of this neurohormonal class as potential profertility agents should be weighed with caution.

Post-coital contraceptive effects of an agonistic analogue of luteinizing hormone releasing hormone

An analogue of synthetic hypothalamic LRH, D-[ALA]6-DES-[GLY]10-PRO9-ethylamide-LRH (Wy-18,481) was evaluated for agonistic (in vivo LH-releasing and ovulation-inducing), post-coital contraceptive and reproductive target organ effects. Both LRH and the analogue terminated pregnancy; there appeared to be a direct relationship between agonistic and post-coital contraceptive potency and activity. The analogue proved to be a potent agonist and both a pre-and post-implantational post-coital anti-fertility agent. In contrast to LRH, the congener did not produce a uterotrophic effect in the hypophysectomized rat. The data suggest that agonist analogue(s) of LRH can terminate pregnancy via hyperstimulation of the pituitary-ovarian-reproductive complex and the use of members of this neurohormonal class as potential clinical pro-fertility agents should be weighted with caution.