isotretinoin and Disease-Models--Animal

Rosacea is one of the most common dermatoses of adults. In recent years many studies have contributed to a better understanding of the pathophysiology of rosacea. They suggest that an altered innate immune response is involved in the vascular and inflammatory manifestations seen in rosacea. A good understanding of the disease and its special features is necessary for the differential diagnosis of the many clinical subtypes and for a stage- and phase-specific treatment approach. Topical treatments that are widely accepted are metronidazole and azelaic acid; agents under investigation that show promise include permethrin, calcineurin inhibitors and sulfur compounds. For systemic therapy antibiotics (tetracyclines, macrolides) and recently doxycycline in anti-inflammatory rather than anti-microbial dosages are used, as well as isotretinoin in severe cases. Findings such as rhinophyma and telangiectases can be treated using different laser systems or dermabrasion. This article gives an overview regarding rosacea, a challenging condition with multiple therapeutic options.

Topics: Adult; Animals; Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Cathelicidins; Dermatologic Agents; Diagnosis, Differential; Disease Models, Animal; Female; Humans; Isotretinoin; Male; Mice; Niacinamide; Rhinophyma; Risk Factors; Rosacea; Skin; Telangiectasis; Ultraviolet Rays

Current models of affective disorders implicate alterations in norepinephrine, serotonin, dopamine, and CRF/cortisol; however treatments targeted at these neurotransmitters or hormones have led to imperfect resolution of symptoms, suggesting that the neurobiology of affective disorders is incompletely understood. Until now retinoids have not been considered as possible contributors to affective disorders. Retinoids represent a family of compounds derived from vitamin A that perform a large number of functions, many via the vitamin A product, retinoic acid. This signaling molecule binds to specific retinoic acid receptors in the brain which, like the glucocorticoid and thyroid hormone receptors, are part of the nuclear receptor superfamily and regulate gene transcription. Research in the field of retinoic acid in the CNS has focused on the developing brain, in part stimulated by the observation that isotretinoin (13-cis retinoic acid), an isomer of retinoic acid used in the treatment of acne, is highly teratogenic for the CNS. More recent work has suggested that retinoic acid may influence the adult brain; animal studies indicated that the administration of isotretinoin is associated with alterations in behavior as well as inhibition of neurogenesis in the hippocampus. Clinical evidence for an association between retinoids and depression includes case reports in the literature, studies of health care databases, and other sources. A preliminary PET study in human subjects showed that isotretinoin was associated with a decrease in orbitofrontal metabolism. Several studies have shown that the molecular components required for retinoic acid signaling are expressed in the adult brain; the overlap of brain areas implicated in retinoic acid function and stress and depression suggest that retinoids could play a role in affective disorders. This report reviews the evidence in this area and describes several systems that may be targets of retinoic acid and which contribute to the pathophysiology of depression.

Topics: Adult; Animals; Brain; Corpus Striatum; Depressive Disorder, Major; Disease Models, Animal; Hippocampus; Humans; Isotretinoin; Mice; Mood Disorders; Neurotransmitter Agents; Prefrontal Cortex; Retrospective Studies; Signal Transduction; Suicide; Tretinoin

The marked efficacy of isotretinoin in the treatment of acne is undoubtedly due to its potential to inhibit sebaceous gland activity. The question arises if the anti-acne effect of new oral retinoids can be predicted by using the currently available experimental models.. We reviewed the effects of various oral retinoids on sebum excretion in humans and their efficacy in acne. The human data were compared to the results obtained from in vitro and animal models.. Oral retinoids such as etretinate, acitretin and the so-called arotinoids were not able to inhibit the sebum production in humans and were ineffective against acne. In various animal models (i.e. sebum production in rats, flank organ size in hamsters, ear sebaceous gland size in hamster, most of these retinoids were shown to be effective. Furthermore, in addition to isotretinoin, some retinoids were able to suppress the proliferation of human sebocytes in vitro.. The elucidation of the mechanism of action of isotretinoin on the sebocyte biology is critical for the search of more reliable models and for the discovery of new retinoids with anti-acne activity.

Topics: Acne Vulgaris; Administration, Oral; Animals; Cells, Cultured; Cricetinae; Dermatologic Agents; Disease Models, Animal; Humans; In Vitro Techniques; Isotretinoin; Rats; Retinoids; Sebaceous Glands; Sebum

In a phase II clinical trial, we sought to determine if combining celecoxib with 13-cis-retinoic acid (13-cRA, Accutane) was efficacious in the treatment of recurrent (progressive) glioblastoma multiforme (GBM). In parallel, we also sought to determine to what extent the outcomes from this clinical trial correlated with the findings from studies utilizing two murine intracerebral GBM models, U87MG and U251HF, to determine the predictive value of these murine models. In the clinical trial, 25 patients were studied at recurrence. Stable disease, which occurred in 44% of the patients, was the best response. The median progression-free survival (PFS) was 8 weeks, with a PFS at 6 months of only 19%. For the patients with stable disease, the median PFS was 24 weeks. The toxicity profile was unremarkable. The modest effect on PFS seen in this study agreed with the recent findings of another study, which showed a 19% PFS at 6 months in patients treated with 13-cRA alone. Thus, the combination of 13-cRA with celecoxib is not more effective than 13-cRA in the treatment of progressive GBM. In the murine model study, we found that long-term dosing with 13-cRA or celecoxib alone or in combination did not increase survival in animals with U87MG tumors but modestly increased survival in animals with U251HF tumors. There was no evidence of synergism between the two drugs. From this, we concluded that the animal studies generally predicted that the two agents would have only a modest effect alone and no additive effect when given in combination to patients.

Topics: Adult; Aged; Animals; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Celecoxib; Disease Models, Animal; Disease-Free Survival; Female; Glioblastoma; Humans; Isotretinoin; Male; Mice; Mice, Nude; Middle Aged; Pyrazoles; Sensitivity and Specificity; Sulfonamides; Survival Analysis

9-cis-Retinoic acid (9-cis-RA) is as active as 13-cis-retinoic acid (13-cis-RA) in inhibiting the proliferation of cultured human sebocytes and in reducing the size of sebaceous glands of hamsters.. Evaluate the anti-acne effect of 9-cis-RA compared to that of 13-cis-RA in a pilot study.. Four young male patients with acne were treated in an open study consecutively with 9-cis-RA and 13-cis-RA given at similar doses.. No beneficial effects were observed with 9-cis-RA in any of the patients whereas all responded favorably to 13-cis-RA.. For the two retinoids tested, the anti-acne effect correlates with the sebosuppressive effect in humans.

Topics: Acne Vulgaris; Administration, Oral; Adolescent; Adult; Alitretinoin; Animals; Cells, Cultured; Cricetinae; Disease Models, Animal; Humans; Isotretinoin; Keratolytic Agents; Male; Pilot Projects; Retinoids; Sebaceous Glands; Sebum; Treatment Outcome; Tretinoin

Benznidazole and nifurtimox are the drugs currently used for the treatment of Chagas disease, however its side effects may affect patient adherence. In the search for new alternative therapies, we previously identified isotretinoin (ISO), an FDA-approved drug widely used for the treatment of severe acne through a drug repurposing strategy. ISO shows a strong activity against Trypanosoma cruzi parasites in the nanomolar range, and its mechanism of action is through the inhibition of T. cruzi polyamine and amino acid transporters from the Amino Acid/Auxin Permeases (AAAP) family. In this work, a murine model of chronic Chagas disease (C57BL/6 J mice), intraperitoneally infected with T. cruzi Nicaragua isolate (DTU TcI), were treated with different oral administrations of ISO: daily doses of 5 mg/kg/day for 30 days and weekly doses of 10 mg/kg during 13 weeks. The efficacy of the treatments was evaluated by monitoring blood parasitemia by qPCR, anti-T. cruzi antibodies by ELISA, and cardiac abnormalities by electrocardiography. No parasites were detected in blood after any of the ISO treatments. The electrocardiographic study of the untreated chronic mice showed a significant decrease in heart rate, while in the treated mice this negative chronotropic effect was not observed. Atrioventricular nodal conduction time in untreated mice was significantly longer than in treated animals. Mice treated even with ISO 10 mg/kg dose every 7 days, showed a significant reduction in anti-T. cruzi IgG levels. In conclusion, the intermittent administration of ISO 10 mg/kg would improve myocardial compromise during the chronic stage.

Topics: Animals; Chagas Disease; Disease Models, Animal; Isotretinoin; Mice; Mice, Inbred C57BL; Nitroimidazoles; Pharmaceutical Preparations; Trypanocidal Agents; Trypanosoma cruzi

Koolen-de Vries syndrome (KdVS) is a rare disorder caused by haploinsufficiency of KAT8 regulatory NSL complex subunit 1 (KANSL1), which is characterized by intellectual disability, heart failure, hypotonia, and congenital malformations. To date, no effective treatment has been found for KdVS, largely due to its unknown pathogenesis. Using siRNA screening, we identified KANSL1 as an essential gene for autophagy. Mechanistic study shows that KANSL1 modulates autophagosome-lysosome fusion for cargo degradation via transcriptional regulation of autophagosomal gene, STX17. Kansl1

Topics: Abnormalities, Multiple; Animals; Autophagosomes; Cerebral Cortex; Chromosome Deletion; Chromosomes, Human, Pair 17; Disease Models, Animal; Female; Haploinsufficiency; HeLa Cells; Humans; Intellectual Disability; Isotretinoin; Lysosomes; Mice; Mice, Transgenic; Mitophagy; Neurons; Nuclear Proteins; Primary Cell Culture

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

To evaluate ocular side effects associated with systemic isotretinoin histopathologically.. In this multicenter study, a total of 15 male and 15 female rats were randomly divided into 3 equal groups according to the oral dose of isotretinoin they were administered: 0 mg/kg/d (group A), 7.5 mg/kg/d (group B), and 15 mg/kg/d (group C). Biopsy specimens were taken from the globe conjunctiva, cornea, and eyelid conjunctiva. Expression levels of human beta-defensin-1, human beta-defensin-2, toll-like receptor (TLR)-2, and TLR-4 were evaluated by immunohistochemical methods.. The number of goblet cells in eyelid conjunctiva was significantly lower in group B than that in group A and group C (P = 0.002). The sizes of meibomian gland acini were significantly smaller in group B and group C than those in group A (P < 0.001). Fibrosis of eyelid conjunctiva was significantly higher in group C and group B than that in group A (P = 0.002). The levels of staining of TLR-4 in the cornea with group B were significantly lower compared with group C (P = 0.035).. Our study suggests that isotretinoin in the early period affects eyelid conjunctiva and meibomian glands without affecting the globe conjunctiva and cornea. Occurrence of the initial symptoms of isotretinoin on the eyelids, especially on the meibomian glands, suggests that the symptoms of patients occur because of evaporative dry eye.

Topics: Administration, Oral; Animals; Biopsy; Conjunctiva; Cornea; Dermatologic Agents; Disease Models, Animal; Eye Diseases; Female; Immunohistochemistry; Isotretinoin; Male; Meibomian Glands; Rats; Rats, Wistar

To uncover the genetic basis of anthracycline-induced cardiotoxicity (AIC), we recently established a genetic suppressor screening strategy in zebrafish. Here, we report the molecular and cellular nature of

Topics: Animals; Bexarotene; Cardiotonic Agents; Cardiotoxicity; Disease Models, Animal; Endothelial Cells; Heart; Humans; Isotretinoin; Myocardium; Neoplasms; Pericardium; Retinoid X Receptor alpha; Zebrafish; Zonula Occludens-1 Protein

Topical isotretinoin is commonly used to treat acne. However, topical isotretinoin has side effects and can hardly permeate through the stratum corneum, the most important skin barrier. Therefore, this study aimed to demonstrate the efficacy of nanoparticles as stable carriers with great curative effects, low side effects, and strong transdermal ability.. In a rabbit model of hyperkeratinization, STCM-ATRA-NPs showed significant therapeutic efficacy. By contrast, negative therapeutic efficacy was observed in a golden hamster model of hyper sebum production. Scanning electron microscopy and Fourier transform infrared spectral analyses showed that nanoparticles could penetrate the stratum corneum. Western blotting demonstrated that the nanoparticles could enhance the transdermal efficacy of isotretinoin by reducing the effect of keratin and tight junction proteins. Further, nanoparticles enhanced endocytosis, thereby promoting drug penetration and absorption into the skin.. STCM-ATRA-NPs were demonstrated to control isotretinoin release, reducing its side effects, and efficiently permeating through the skin by reducing the effect of keratin and tight junction proteins and enhancing endocytosis.

Topics: Acne Vulgaris; Administration, Cutaneous; Animals; Cell Membrane; Dermatologic Agents; Disease Models, Animal; Drug Carriers; Human Umbilical Vein Endothelial Cells; Humans; Isotretinoin; Male; Mesocricetus; Nanoparticles; Rabbits; Skin; Skin Absorption; Stem Cells

This study was aimed to develop Isotretinoin (ITN) and α-tocopherol acetate (α-TA) loaded solid lipid nanoparticle topical gel for better skin sensitivity and potentiation of efficacy.. ITN and α-TA-loaded solid lipid nanoparticles (AE-SLN) were prepared by microemulsion method with glyceryl mono-stearate as lipid and tween 80: butanol as surfactant. AE-SLNs had mean particle size of 193.4 nm (zeta-potential -29 mV) and entrapment efficiency of 84%w/w for ITN and 77.4%w/w for α-TA. AE-SLN gel showed sustained drug release for 24 h with a final cumulative release of 95.8% w/w and 89.1%w/w for ITN and α-TA. AE-SLN gel showed no erythema or edoema in rabbits and potent efficacy in rat model of acne.. In conclusion, AE-SLN gel has the potential to use as a non-irritant topical formulation for the treatment of acne.

Topics: Acne Vulgaris; Administration, Cutaneous; Administration, Topical; alpha-Tocopherol; Animals; Butanols; Disease Models, Animal; Drug Carriers; Drug Delivery Systems; Drug Liberation; Female; Gels; Hydrogen-Ion Concentration; In Vitro Techniques; Isotretinoin; Lipids; Male; Microscopy, Electron, Scanning; Nanoparticles; Particle Size; Polysorbates; Rabbits; Rats; Rats, Wistar; Skin Absorption; Surface-Active Agents

Acne is a common inflammatory skin disease with the dysregulation of innate and adaptive immunity. However, the underlying mechanism of acne has not been completely elucidated. In this study, we identified gene signatures and the immune-related regulatory network in acne using integrated bioinformatics methods. Here, 303 Differentially expressed genes (DEGs) and 28 Hub genes were identified in acne (GSE53795 and GSE108110), which were associated with the inflammation-related signaling pathway. Subsequently, the CIBERSORT algorithm revealed the increased proinflammatory cells in acne. Moreover, we identified 3 kinases (FGR, HCK and LYN) and 2 transcription factors (TFs) (IRF8 and ZBTB16) from DEGs as the key genes, which regulated immune cell infiltration via targeting immune-related genes in acne. The upregulated 3 kinases (FGR, HCK and LYN) and IRF8, and the downregulated ZBTB16 were also confirmed in GSE6475 and in Acne mice. Based on the expression levels of these key genes, the tissues could be divided into 2 clusters using consensus cluster analysis. GSEA analysis showed that inflammation-related signaling pathways significantly enriched in cluster 2, indicating the important role of kinase and TFs on immune regulation in acne. Finally, we found that isotretinoin and trifarotene (CD5789) treatment repressed the expression of immune genes but not the expression of the kinases and TFs, indicating that kinases and TFs may be novel therapeutic target for acne. In conclusion, 3 kinases and 2 TFs were identified and validated as key regulators in the immune-related regulatory networks in acne, providing a more comprehensive understanding and novel therapeutic targets of acne.

Topics: Acne Vulgaris; Animals; Cluster Analysis; Computational Biology; Databases, Genetic; Dermatologic Agents; Disease Models, Animal; Gene Expression Regulation; Gene Ontology; Gene Regulatory Networks; Humans; Isotretinoin; Mice, Inbred BALB C; Phosphotransferases; Protein Interaction Maps; Retinoids; Signal Transduction; Skin; Transcription Factors; Transcriptome

There is a major clinical need for new therapies for the treatment of chronic itch. Many of the molecular components involved in itch neurotransmission are known, including the neuropeptide NPPB, a transmitter required for normal itch responses to multiple pruritogens in mice. Here, we investigated the potential for a novel strategy for the treatment of itch that involves the inhibition of the NPPB receptor NPR1 (natriuretic peptide receptor 1). Because there are no available effective human NPR1 (hNPR1) antagonists, we performed a high-throughput cell-based screen and identified 15 small-molecule hNPR1 inhibitors. Using in vitro assays, we demonstrated that these compounds specifically inhibit hNPR1 and murine NPR1 (mNPR1). In vivo, NPR1 antagonism attenuated behavioral responses to both acute itch- and chronic itch-challenged mice. Together, our results suggest that inhibiting NPR1 might be an effective strategy for treating acute and chronic itch.

Topics: Animals; Behavior, Animal; Cell-Free System; Dermatitis, Contact; Disease Models, Animal; Ganglia, Spinal; Humans; Mice, Inbred C57BL; Mice, Knockout; Neurons; Pruritus; Receptors, Atrial Natriuretic Factor; Reproducibility of Results; Signal Transduction; Small Molecule Libraries

Overactive bladder (OAB) coexists with depression in women. Here, we assessed the effects of a 1-week treatment with blebbistatin, a myosin II inhibitor, on changes in behavior and detrusor overactivity (DO) symptoms induced by a 6-week administration of 13-cis-retinoic acid (13-cis-RA), with the aid of the forced swim test (FST), spontaneous locomotor activity test, and in vivo cystometric investigations in female Wistar rats. 13-cis-RA-induced depressive-like behavior and DO symptoms were associated with increased corticotropin-releasing factor (CRF) level in the plasma, prefrontal cortex (PFC), hippocampus (Hp), Barrington's nucleus (BN), and urinary bladder. Moreover, 13-cis-RA decreased brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) levels in plasma, PFC, Hp, and BN, while it increased BDNF and NGF levels in urinary bladder. Blebbistatin exerted antidepressant-like effect and attenuated changes in the cystometric parameters as well as the central and peripheral levels of CRF, BDNF, and NGF that were induced by 13-cis-RA, while it did not affect urine production, mean, systolic or diastolic blood pressure, or heart rate. The results point to blebbistatin as a potential treatment option for OAB coexisting with depression.

Topics: Animals; Antidepressive Agents; Autonomic Agents; Brain; Brain-Derived Neurotrophic Factor; Corticotropin-Releasing Hormone; Depression; Disease Models, Animal; Female; Heterocyclic Compounds, 4 or More Rings; Isotretinoin; Myosin Type II; Nerve Growth Factor; Random Allocation; Rats, Wistar; Urinary Bladder; Urinary Bladder, Overactive

Topics: Animals; Antiviral Agents; Cell Survival; Disease Models, Animal; DNA, Viral; Down-Regulation; Gene Expression; Hepatitis B; Hepatitis B e Antigens; Hepatitis B Surface Antigens; Hepatitis B virus; Hepatocytes; Humans; Isotretinoin; Male; Mice; Mice, Inbred BALB C; Retinoids; RNA, Viral; Up-Regulation; Virus Replication

The precise molecular basis of retinoid embryopathy is yet unknown. This hypothesis predicts that isotretinoin (13-cis retinoic acid), the prodrug of all-trans retinoic acid (ATRA), exaggerates neural crest cell (NCC) apoptosis via upregulation of the pro-apoptotic transcription factor p53, the guardian of the genome. Increased p53 signalling is associated with Treacher Collins-, CHARGE- and fetal alcohol syndrome, which exhibit dysmorphic craniofacial features resembling retinoid embryopathy. In addition, developmental studies of NCC homeostasis in the zebrafish support the pivotal role of p53. Translational evidence implies that isotretinoin-stimulated overactivation of p53 during embryogenesis represents the molecular basis of isotretinoin's teratogenicity.

Topics: Animals; Apoptosis; CHARGE Syndrome; Disease Models, Animal; Embryonic Development; Fetal Alcohol Spectrum Disorders; Homeostasis; Humans; Isotretinoin; Mandibulofacial Dysostosis; Neural Crest; Signal Transduction; Teratogens; Translational Research, Biomedical; Tretinoin; Tumor Suppressor Protein p53; Up-Regulation; Zebrafish

Acne is the most common skin disorder and can directly affect the patients' self-esteem. Systemic treatment has been indicated for nodular, cystic or persistent acne rather than another type of treatment, such as a topic one. Isotretinoin is an analogue of vitamin A and by suppressing the sebaceous glands the disease can be controlled. This study was designed to mimic the treatment performed in young patients using the dosage of 1mg/kg, and a higher one of 10mg/kg, for 60days in young male Wistar rats. 24 Wistar rats were divided into four groups: control(water), D0(soybean oil, control group), D1(1mg/kg of Isotretinoin solution), D10(10mg/kg of Isotretinoin solution). Using the morphometry tool and histochemical techniques we evaluated the villus, intestinal crypts, and goblet cells to find signs of possible alterations of the duodenum, jejunum and ileum segments of the small intestine. We found no signs of changes in the jejunum mucosa after 60 days of treatment with 1mg/kg and 10mg/kg. The duodenum is also less affected, whereas significant modifications were found in the ileum. The goblet cell frequency was altered, indicating a proliferative potential for the substance. Although some patients have described intestinal symptoms, no important alterations were found with this protocol, reaffirming the security involved in the treatment with this substance.

Topics: Acne Vulgaris; Animals; Disease Models, Animal; Duodenum; Goblet Cells; Humans; Ileum; Intestinal Mucosa; Intestine, Small; Isotretinoin; Jejunum; Male; Rats; Rats, Wistar

The subjective measures used to study mood disorders in humans cannot be replicated in animals; however, the increasing application of objective neuropsychological methods provides opportunities to develop translational animal tasks. Here we describe a novel behavioral approach, which has enabled us to investigate similar affective biases in rodents. In our affective bias test (ABT), rats encounter two independent positive experiences--the association between food reward and specific digging substrate--during discrimination learning sessions. These are performed on separate days under either neutral conditions or during a pharmacological or affective state manipulation. Affective bias is then quantified using a preference test where both previously rewarded substrates are presented together and the rat's choices recorded. The absolute value of the experience is kept consistent and all other factors are counterbalanced so that any bias at recall can be attributed to treatment. Replicating previous findings from studies in healthy volunteers, we observe significant positive affective biases following acute treatment with typical (fluoxetine, citalopram, reboxetine, venlafaxine, clomipramine) and atypical antidepressants (agomelatine, mirtazapine), and significant negative affective biases following treatment with drugs associated with inducing negative affective states in humans (FG7142, rimonabant, 13-cis retinoic acid). We also observed that acute psychosocial stress and environmental enrichment induce significant negative and positive affective biases, respectively, and provide evidence that these affective biases involve memory consolidation. The positive and negative affective biases induced in our test also mirror the antidepressant and pro-depressant effects of these drugs in patients suggesting our test has both translational and predictive validity. Our results suggest that cognitive affective biases could contribute to drug- or stress-induced mood changes in people and support the hypothesis that a cognitive neuropsychological mechanism contributes to antidepressant drug efficacy.

Topics: Affect; Animals; Antidepressive Agents; Appetite Depressants; Cannabinoid Receptor Antagonists; Carbolines; Depression; Discrimination Learning; Disease Models, Animal; Environment; Isotretinoin; Male; Piperidines; Pyrazoles; Rats; Reward; Rimonabant; Stress, Psychological; Translational Research, Biomedical

The combination of isotretinoin (13-cis-retinoic acid) with antiestrogens seems to be a promising strategy for cancer chemotherapy. The aim of the study was to evaluate the effects of isotretinoin alone or in combination with 4-hydroxytamoxifen (OHTAM) and with its prodrug tamoxifen (TAM), on the functions of rat liver mitochondria, i.e., mitochondrial permeability transition (MPT), bioenergetic functions and adenine nucleotide translocase (ANT). Isotretinoin (5 nmol/mg protein) induced the Ca²⁺-dependent MPT pore opening in mitochondria energized with succinate, which was prevented by OHTAM, cyclosporine A, TAM and ANT ligands. When mitochondria were energized with glutamate/malate and in the absence of added Ca²⁺ isotretinoin decreased the state 3 respiration, the ATP levels, the active ANT content and increased the lag phase of the phosphorylation cycle, demonstrating that isotretinoin decreased the mitochondrial phosphorylation efficiency. These changes of isotretinoin in bioenergetic parameters were not significant in the presence of succinate. The effects of isotretinoin at 5 nmol/mg protein on the Ca²⁺-dependent MPT and phosphorylative efficacy may be related with interactions with the ANT. Above 10 nmol/mg protein isotretinoin strongly diminished the active ANT content, decreased the Δψ, inhibited the complex I and induced proton leak through the Fo fraction of complex V. The combination of OHTAM with isotretinoin only induced significant changes in the energy production systems at concentrations ≥5 nmol isotretinoin/mg protein. Therefore, our results suggest that isotretinoin-associated liver toxicity is possibly related with mitochondrial dysfunctions and that the combination with OHTAM may contribute to decrease its toxicity.

Topics: Animals; Antineoplastic Agents, Hormonal; Antineoplastic Combined Chemotherapy Protocols; Cell Membrane Permeability; Disease Models, Animal; Drug Interactions; Energy Metabolism; Estrogen Receptor Modulators; Isotretinoin; Membrane Potential, Mitochondrial; Mitochondria, Liver; Mitochondrial ADP, ATP Translocases; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Oxidative Phosphorylation; Rats; Rats, Wistar; Tamoxifen

In vitro and in vivo data have shown that retinoid treatment promotes an anti-inflammatory milieu with few adverse effects toward the gastrointestinal tract. The in vivo studies reported here further evaluate retinoid effects in 2 mouse models of inflammatory bowel disease.. Chronic dextran sulfate sodium colitis was induced in age- and weight-matched C57Bl/6 mice by 4 cycles of dextran sulfate sodium administration (6-8 animals/group). At cycle 4, animals were administered 13-cis-retinoic acid (isotretinoin, 30 mg/kg) or vehicle (oral gavage) or 4-oxo-13-cis-retinoic acid (15 mg/kg, intraperitoneal) daily. T-cell transfer colitis was induced in CB17 SCID mice by transfer of naive CD4CD62L T cells and treated by transfer of regulatory CD4CD25 T cells (4-6 animals/group); isolated from BALB/c mice after treatment with isotretinoin or vehicle, as above, for 2 weeks. Assessments included endoscopic and histological scores, myeloperoxidase activity, serum cytokines, and plasma isotretinoin levels.. Retinoid-treated animals with colitis showed comparable changes in myeloperoxidase activity, and endoscopic and histological scores, versus untreated animals with colitis. Modest and comparable changes were seen in body weight and colon length in animals injected with naive T cells from isotretinoin-treated donors versus those injected with T cells from vehicle-treated donors. Retinoid treatment was consistently associated with lower interleukin-12 levels, which, after the transfer of naive T cells from isotretinoin-treated donors, supported isotretinoin-mediated predisposition of naive T cells toward reduced proinflammatory cytokine expression. Colitis had no effect on isotretinoin exposure.. Retinoids attenuate the proinflammatory cytokine response in vivo, with only modest effects on body weight and parameters of gastrointestinal morphology.

Topics: Animals; CD4-Positive T-Lymphocytes; Colitis; Cytokines; Dermatologic Agents; Dextran Sulfate; Disease Models, Animal; Female; Flow Cytometry; Gastrointestinal Tract; Isotretinoin; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, SCID; Peroxidase; T-Lymphocytes, Regulatory

Patients with pancreatic ductal adenocarcinoma are deficient in vitamin A, resulting in activation of pancreatic stellate cells (PSCs). We investigated whether restoration of retinol to PSCs restores their quiescence and affects adjacent cancer cells.. PSCs and cancer cell lines (AsPc1 and Capan1) were exposed to doses and isoforms of retinoic acid (RA) in 2-dimensional and 3-dimensional culture conditions (physiomimetic organotypic culture). The effects of all-trans retinoic acid (ATRA) were studied in LSL-KrasG12D/+;LSL-Trp53R172H/+;Pdx-1-Cre mice, a model of human pancreatic ductal adenocarcinoma.. After incubation with ATRA, PSCs were quiescent and had altered expression of genes that regulate proliferation, morphology, and motility; genes that encode cytoskeletal proteins and cytokines; and genes that control other functions, irrespective of culture conditions or dosage. In the organotypic model, and in mice, ATRA induced quiescence of PSCs and thereby reduced cancer cell proliferation and translocation of β-catenin to the nucleus, increased cancer cell apoptosis, and altered tumor morphology. ATRA reduced the motility of PSCs, so these cells created a "wall" at the junction between the tumor and the matrix that prevented cancer cell invasion. Restoring secreted frizzled-related protein 4 (sFRP4) secretion to quiescent PSCs reduced Wnt-β-catenin signaling in cancer cells and their invasive ability. Human primary and metastatic pancreatic tumor tissues stained strongly for cancer cell nuclear β-catenin but had low levels of sFRP4 (in cancer cells and PSCs).. RA induces quiescence and reduces motility of PSCs, leading to reduced proliferation and increased apoptosis of surrounding pancreatic cancer cells. RA isoforms might be developed as therapeutic reagents for pancreatic cancer.

Topics: Alitretinoin; Animals; Antineoplastic Agents; Apoptosis; beta Catenin; Carcinoma, Pancreatic Ductal; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cellular Senescence; Disease Models, Animal; Disease Progression; Dose-Response Relationship, Drug; Gene Expression Regulation, Neoplastic; Humans; Isotretinoin; Mice; Mice, Mutant Strains; Pancreatic Neoplasms; Pancreatic Stellate Cells; Paracrine Communication; Proto-Oncogene Proteins; RNA Interference; Signal Transduction; Time Factors; Transcription, Genetic; Tretinoin; Wnt Proteins

Retinoids, vitamin A related compounds, have an established role in the development of the nervous system and are increasingly recognized to play a role in adult brain function. The synthetic retinoid, 13-cis-retinoic acid (13-cis-RA, Roaccutane) is widely used to treat severe acne but has been linked to an increased risk of neuropsychiatric side effects, including depression. Here we report that chronic administration with 13-cis-RA (1 mg/kg i.p. daily, 7-14 days) in adult rats reduced aggression- and increased flight-related behaviours in the resident-intruder paradigm. However, in the forced swim, sucrose consumption and open field tests treatment for up to 6 weeks with 13-cis-RA did not modify behaviour in adult or juvenile animals. The behavioural change observed in the resident-intruder paradigm is directly opposite to that observed with chronic antidepressant administration. These findings indicate that when a suitably sensitive behavioural test is employed then chronic administration of 13-cis-RA in adult rats induces behavioural changes consistent with a pro-depressant action.

Topics: Age Factors; Aggression; Analysis of Variance; Animals; Depression; Dermatologic Agents; Disease Models, Animal; Drug Administration Schedule; Escape Reaction; Exploratory Behavior; Food Preferences; Isotretinoin; Male; Motor Activity; Rats; Rats, Wistar; Sucrose; Sweetening Agents; Swimming; Time Factors

Redox imbalance elicited by oxidative stress contributes to pathogenic remodeling of ion channels that underlies arrhythmogenesis and contractile dysfunction in the failing heart. This study examined whether the expression of K(+) channels in the remodeled ventricle is controlled by the thioredoxin system, a principal oxidoreductase network regulating redox-sensitive proteins. Ventricular dysfunction was induced in rats by coronary artery ligation, and experiments were conducted 6-8 wk postinfarction. Biochemical assays of tissue extracts from infarcted hearts showed that thioredoxin reductase activity was decreased by 32% from sham-operated controls (P < 0.05), whereas thioredoxin activity was 51% higher postinfarction (P < 0.05). These differences in activities paralleled changes in protein abundance as determined by Western blot analysis. However, whereas real-time PCR showed thioredoxin reductase mRNA levels to be significantly decreased postinfarction, thioredoxin mRNA was not altered. In voltage-clamp studies of myocytes from infarcted hearts, the characteristic downregulation of transient-outward K(+) current density was reversed by exogenous pyruvate (5 mmol/l), and this effect was blocked by the specific inhibitors of the thioredoxin system: auranofin or 13-cis-retinoic acid. Real-time PCR and Western blot analyses of myocyte suspensions from infarcted hearts showed that pyruvate increased mRNA and protein abundance of Kv4.2 and Kv4.3 channel alpha-subunits as well as the accessory protein KChIP2 when compared with time-matched, untreated cells (P < 0.05). The pyruvate-induced increase in Kv4.x expression was blocked by auranofin, but the upregulation of KChIP2 expression was not affected. These data suggest that the expression of Kv4.x channels is redox-regulated by the thioredoxin system, which may be a novel therapeutic target to reverse or limit electrical remodeling of the failing heart.

Topics: Animals; Auranofin; Blotting, Western; Disease Models, Animal; Heart Failure; Isotretinoin; Kv Channel-Interacting Proteins; Male; Membrane Potentials; Myocardial Infarction; Myocardium; Oxidation-Reduction; Oxidative Stress; Patch-Clamp Techniques; Potassium; Pyruvic Acid; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Shal Potassium Channels; Thioredoxin-Disulfide Reductase; Thioredoxins; Ventricular Remodeling

13-cis-retinoic acid (13-cis-RA, isotretinoin) is used to treat severe recalcitrant acne. Other retinoids have adverse effects on bone. Recent studies of human patients treated with 13-cis-RA have had varying results, perhaps because of variability among patients and the lack of control groups. The effects of retinoids have been studied in rodents, but little information is available regarding the effects of clinically relevant retinoid doses as evaluated by use of bone densitometric techniques. We treated rats for 15 or 20 wk with 13-cis-RA, all-trans-RA, or soybean oil (control) by gavage. We used dual-energy X-ray absorptiometry, histomorphometry, and histologic evaluation to evaluate effects on bone. Spontaneous long bone fractures occurred in some rats treated with 15 mg/kg all-trans-RA daily. Bone mineral density, bone mineral content, bone diameter, and cortical thickness of the femur were reduced in rats treated daily with 10 or 15 mg/kg all-trans-RA or 30 mg/kg 13-cis-RA. The lumbar spine was not affected. Although the effects of 13-cis-RA were not as dramatic as those of all-trans-RA, further study of the effects of 13-cis-RA on long bones is warranted.

Topics: Absorptiometry, Photon; Administration, Oral; Animals; Bone Density; Bone Resorption; Dermatologic Agents; Disease Models, Animal; Female; Humans; Isotretinoin; Male; Osteoporosis; Rats; Rats, Sprague-Dawley; Species Specificity; Tretinoin

Recessive Stargardt's macular degeneration is an inherited blinding disease of children caused by mutations in the ABCR gene. The primary pathologic defect in Stargardt's discase is accumulation of toxic lipofuscin pigments such as N-retinylidene-N-retinylethanolamine (A2E) in cells of the retinal pigment epithelium (RPE). This accumulation appears to be responsible for the photoreceptor death and severe visual loss in Stargardt's patients. Here, we tested a novel therapeutic strategy to inhibit lipofuscin accumulation in a mouse model of recessive Stargardt's disease. Isotretinoin (Accutane) has been shown to slow the synthesis of 11-cis-retinaldehyde (11cRAL) and regeneration of rhodopsin by inhibiting 11-cis-retinol dehydrogenase (11cRDH) in the visual cycle. Light activation of rhodopsin results in its release of all-trans-retinaldehyde (atRAL), which constitutes the first reactant in A2E biosynthesis. Accordingly, we tested the effects of isotretinoin on lipofuscin accumulation in abcr-/- knockout mice. Isotretinoin blocked the formation of A2E biochemically and the accumulation of lipofuscin pigments by electron microscopy. We observed no significant visual loss in treated abcr-/- mice by electroretinography. Isotretinoin also blocked the slower, age-dependent accumulation of lipofuscin in wild-type mice. These results corroborate the proposed mechanism of A2E biogenesis. Further, they suggest that treatment with isotretinoin may inhibit lipofuscin accumulation and thus delay the onset of visual loss in Stargardt's patients. Finally, the results suggest that isotretinoin may be an effective treatment for other forms of retinal or macular degeneration associated with lipofuscin accumulation.

Topics: Animals; Disease Models, Animal; Enzyme Inhibitors; Esters; Isotretinoin; Lipofuscin; Macular Degeneration; Mice; Retinaldehyde; Time Factors

To investigate the effect of transcription-modulating drugs, fenofibrate and isotretinoin, on metabolic profile, insulin sensitivity of adipose and muscle tissues and gene expression in a genetic model of insulin resistance syndrome, polydactylous rat strain (PD/Cub).. Administration of fenofibrate (100 mg/kg/day), isotretinoin (30 mg/kg/day) or vehicle to adult male PD/Cub rats fed standard laboratory chow for 15 days.. Parameters of lipid and carbohydrate metabolism-oral glucose tolerance test, serum concentrations of insulin, triglycerides (TG), free fatty acids (FFA), glycerol, total cholesterol (CH); morphometric variables, in vitro insulin sensitivity of adipose and muscle tissues, catecholamine-stimulated lipolysis and the expression of ApoC-III and Hnf-4 genes in liver.. Both experimental groups displayed an increase in adiposity with contrasting effects on TG (lowered by fenofibrate and increased by isotretinoin) and gene expression (no change in fibrate-treated rats and increased expression of ApoC-III and Hnf-4 in isotretinoin-treated group). Fenofibrate-treated rats also showed decreased concentrations of FFA and CH with concomitant decrease of catecholamine-induced lipolysis in adipocytes, but also hyperinsulinemia and the highest insulin/glucose ratio. Isotretinoin increased glycerol concentrations and decreased the insulin sensitivity of peripheral tissues.. The PD/Cub rat showed a distinct pharmacogenetic reaction to fenofibrate and isotretinoin administration. Several lines of evidence now implicate specific variant(s) of ApoC-III and/or ApoA-V alleles as responsible for the dyslipidemia observed in this genetic model. The PD/Cub strain may also serve as a pharmacogenetic model for dissection of the retinoid-induced hypertriglyceridemia.

Topics: Adipose Tissue; Animals; Apolipoprotein C-III; Apolipoproteins C; Disease Models, Animal; DNA-Binding Proteins; Fenofibrate; Gene Expression Regulation; Glucose Tolerance Test; Hepatocyte Nuclear Factor 4; Hypertriglyceridemia; Hypolipidemic Agents; Insulin; Insulin Resistance; Isotretinoin; Lipids; Lipolysis; Male; Muscle, Skeletal; Obesity; Organ Size; Phosphoproteins; Rats; Rats, Inbred Strains; Transcription Factors

Recessive Stargardt's macular degeneration is a blinding disease of children caused by mutations in the ABCA4 (ABCR) gene. Mice with a knockout mutation in abcr accumulate toxic lipofuscin pigments in ocular tissues, similar to affected humans. The major fluorophore of lipofuscin is the bis-retinoid, N-retinylidene-N-retinylethanolamine (A2E). In the current study, we sought to define the effect of increasing light on A2E accumulation. We crossed the abcr(-/-) mutation onto an albino background. The retinoid profiles in albino mice indicated higher retinal illuminance than in pigmented mice exposed to similar ambient light. Unexpectedly, A2E levels were not higher in the albino mice. Also, A2E levels in abcr(-/-) mice reared under cyclic light at 30, 120, or 1,700 lux were similar. Thus, increased retinal illuminance was not correlated with higher A2E. A2E has been shown to undergo light-dependent oxidation to yield a series of A2E epoxides or oxiranes. These oxiranes react with DNA in vitro, suggesting a potential mechanism for A2E cytotoxicity. We analyzed ocular tissues from abcr(-/-) mice for A2E oxiranes by mass spectrometry. Unlike A2E, the oxiranes were more abundant in albino vs. pigmented abcr(-/-) mice, and in abcr(-/-) mice exposed to increasing ambient light. These observations suggest that both the biosynthesis of A2E and its conversion to oxiranes are accelerated by light. Finally, we showed that the formation of A2E oxiranes is strongly suppressed by treating the abcr(-/-) mice with Accutane (isotretinoin), an inhibitor of rhodopsin regeneration.

Topics: Adaptation, Physiological; Animals; ATP-Binding Cassette Transporters; Chromatography, High Pressure Liquid; Disease Models, Animal; Ethylene Oxide; Isotretinoin; Light; Macular Degeneration; Mass Spectrometry; Mice; Mice, Inbred BALB C

The present paper assesses the chemopreventive potential of retinoic acid on benzoyl peroxide (BPO)-induced cutaneous tumor promotion response and oxidative stress in murine skin. In this study, we have shown the activities of cutaneous antioxidant enzymes and phase II metabolizing enzymes and the glutathione content were decreased while epidermal ornithine decarboxylase (ODC) activity and DNA synthesis were induced in benzoyl peroxide treated animals. Topical application of retinoic acid resulted in significant inhibition of benzoyl peroxide-induced epidermal ornithine decarboxylase activity and DNA synthesis. Application of retinoic acid at three different doses prior to the application of benzoyl peroxide recovered the depleted level of glutathione, inhibited activities of antioxidant and phase II metabolizing enzymes, thus resulting in significant inhibition of oxidative stress in dose dependent manner. Enhanced susceptibility of cutaneous microsomal lipid peroxidation and xanthine oxidase activity were significantly reduced (P > 0.05). The antimutagenic effect of retinoic acid was tested against benzoyl peroxide mediated mutagenicity in Salmonella typhimurium strain TA-98 and TA-100 using 3-methyl cholanthrene-induced murine skin (S9 fraction) as the metabolic activation system. Indeed, with the addition of various concentrations of retinoic acid there was significant reduction in the number of revertants per plate in concentration dependent manner. In summary, our data indicates that retinoic acid may exhibit cancer chemopreventive activity in skin tumorigenesis model.

Topics: Administration, Topical; Animals; Benzoyl Peroxide; Biomarkers, Tumor; Cell Division; Disease Models, Animal; Glutathione Peroxidase; Glutathione Reductase; Isotretinoin; Male; Mice; Oxidative Stress; Sensitivity and Specificity; Skin; Skin Neoplasms

Recessive Stargardt's macular degeneration is an inherited blinding disease of children caused by mutations in the ABCR gene. The primary pathologic defect in Stargardt's disease is accumulation of toxic lipofuscin pigments such as N-retinylidene-N-retinylethanolamine (A2E) in cells of the retinal pigment epithelium. This accumulation appears to be responsible for the photoreceptor death and severe visual loss in Stargardt's patients. Here, we tested a therapeutic strategy to inhibit lipofuscin accumulation in a mouse model of recessive Stargardt's disease. Isotretinoin (Accutane) has been shown to slow the synthesis of 11-cis-retinaldehyde and regeneration of rhodopsin by inhibiting 11-cis-retinol dehydrogenase in the visual cycle. Light activation of rhodopsin results in its release of all-trans-retinaldehyde, which constitutes the first reactant in A2E biosynthesis. Accordingly, we tested the effects of isotretinoin on lipofuscin accumulation in abcr(-/-) knockout mice. Isotretinoin blocked the formation of A2E biochemically and the accumulation of lipofuscin pigments by electron microscopy. We observed no significant visual loss in treated abcr(-/-) mice by electroretinography. Isotretinoin also blocked the slower, age-dependent accumulation of lipofuscin in wild-type mice. These results corroborate the proposed mechanism of A2E biogenesis. Further, they suggest that treatment with isotretinoin may inhibit lipofuscin accumulation and thus delay the onset of visual loss in Stargardt's patients. Finally, the results suggest that isotretinoin may be an effective treatment for other forms of retinal or macular degeneration associated with lipofuscin accumulation.

Topics: Animals; ATP-Binding Cassette Transporters; Dark Adaptation; Disease Models, Animal; Genes, Recessive; Humans; Isotretinoin; Lipofuscin; Macular Degeneration; Mice; Mice, Knockout; Microscopy, Electron; Models, Biological; Pigment Epithelium of Eye; Pyridinium Compounds; Retinal Pigments; Retinoids; Rod Cell Outer Segment

Histopathological evaluation of the mammary gland tumours of Sprague-Dawley rats induced with 1-methyl-1-nitrosourea (MNU), and treated with either CpG oligodeoxynucleotides (CpG-ODN) and/or 13-cis retinoic acid has been performed in this work. Since, the treatment of animals with CpG-ODN induced a significant decrease of tumour burden and volume in comparison with MNU treated control group (Macejova et al. 2001), it was of high impact to compare histological appearance of tumours in different experimental groups (MNU, CpG-ODN, 13-cis retinoic acid, CpG-ODN plus 13-cis retinoic acid). We have found reduced number of carcinomas with necroses in the CpG motifs treated group when compared to animals treated with MNU only. From the histological point of view the treatment with the CpG-ODN may have some protective effect. Carcinoma patterns proportion in the group treated with CpG-ODN was found to be different in comparison with other experimental groups. Treatment of rats with CpG-ODN had no apparent effect on invasiveness of developed carcinomas.

Topics: Adenocarcinoma; Adjuvants, Immunologic; Animals; CpG Islands; Disease Models, Animal; Drug Therapy, Combination; Female; Isotretinoin; Mammary Neoplasms, Experimental; Methylnitrosourea; Oligodeoxyribonucleotides; Rats; Treatment Outcome

Vitamin A and its derivatives (retinoids) have been known to cause premature epiphyseal closure in humans as an unwanted side effect of chronic treatment. The purpose of the present study was to determine if guinea pigs could serve as an animal model of retinoid-induced epiphyseal plate closure, and to utilize this model to study the mechanism. Weanling male Hartley guinea pigs were treated ip via osmotic pump for up to 14 days with vehicle or 0.50 to 5.5 mg/kg/day of the retinoic acid receptor (RAR)-selective agonist AGN 190121. Histopathological examination of the proximal tibia of AGN 190121-treated guinea pigs revealed a dose-dependent disruption of the epiphyseal plate. The natural retinoids all-trans-retinoic acid and 13-cis-retinoic acid also induced epiphyseal plate closure in guinea pigs when administered by ip injection for 10 days. Prominent histological features of retinoid-induced epiphyseal closure included the loss of basophilic staining in the extracellular matrix of epiphyseal plate chondrocytes and the invasion of the epiphyseal plate by osteoclasts. To determine if the epiphyseal closure detected histologically was reversible, guinea pigs were treated for 6 days with the RAR-selective agonist (E)-4[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)propen- 1-y1]benzoic acid (TTNPB) or vehicle, and groups of guinea pigs were euthanized on Day 7 or 57. TTNPB but not vehicle treatment caused histological evidence of epiphyseal closure at both time points, and significant bone elongation between Day 7 and Day 57 was detected only in vehicle-treated animals. Epiphyseal closure and other toxic effects of TTNPB were blocked by cotreatment of guinea pigs with a fivefold molar excess of AGN 193109, an RAR antagonist. Taken together, these data demonstrate the utility of the guinea pig as an animal model of retinoid-induced epiphyseal closure and suggest that RAR activation is necessary and sufficient for this activity.

Topics: Animals; Benzoates; Disease Models, Animal; Growth Plate; Guinea Pigs; Isotretinoin; Male; Receptors, Retinoic Acid; Tretinoin

Liarozole fumarate (R85,246), a novel benzimidazole derivative, reduced s.c. and bone metastasis tumor growth by the androgen-independent PC-3ML-B2 human prostatic carcinoma clone in SCID mice. The drug inhibited cell invasion of Matrigel in Boyden chamber chemotactic assays and the secretion of type IV collagenase. In vitro, liarozole failed to inhibit cell proliferation and cell attachment to various substrates (Matrigel, laminin, type IV collagen, and fibronectin). In vivo, the drug also blocked type IV collagenase production in established s.c. tumors. Liarozole has been postulated by others (R. De Coster, W. Wouters, R. Van Ginckel, D. End, et al. J. Steroid Biochem. Mol. Biol., 43: 197-201, 1992) to inhibit retinoic acid catabolism. Our data indicate that liarozole treatment can increase the tumor retinoic acid levels in vivo. Studies of retinoic acid revealed that the drug independently reduced tumor growth in vivo and inhibited cell invasion of Matrigel and the secretion of collagenase IV. Surprisingly, liarozole and retinoic acid failed to exhibit measurable synergistic activity both in vitro and in vivo. Taken together these data suggest that liarozole might inhibit retinoic acid catabolism in vivo and consequently have significant therapeutic value as an anti-prostatic tumor agent.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Bone Neoplasms; Cell Adhesion; Cell Division; Cell Survival; Chemotactic Factors; Collagenases; Disease Models, Animal; Humans; Imidazoles; Isotretinoin; Male; Matrix Metalloproteinase 9; Mice; Mice, SCID; Neoplasm Invasiveness; Neoplasm Transplantation; Prostatic Neoplasms; Tumor Cells, Cultured

In developing an avian model for 13-cis-retinoic acid (13cisRA) embryopathy, we found 13cisRA induced cardiovascular defects, especially Type I ventricular septal defects (VSDs) (Hart et al.: Teratology 41:463-472, '90). As the first step of investigating possible mechanisms, we have examined the light microscopic morphology of RA-induced cardiovascular defects in chick embryos. Fertilized eggs were injected via yolk sac with 150 micrograms 13cisRA in dimethylsulfoxide (DMSO), DMSO or mock injection on embryonic day 5 (E5). On E6, E7, or E8, surviving embryos were sacrificed and fixed in 10% formalin. Thoracic blocks were exised, embedded in paraffin and serially sectioned through the heart, base to apex. Slides were stained, screened for tissue orientation, then coded and evaluated without knowledge of treatment group. Examination of serial sections permitted qualitative evaluation of conotruncal ridge volume, mesenchymal organization, necrosis and extent of fusion. Extent of fusion was the only parameter influenced by 13cisRA treatment. On E6, ridge fusion was incomplete in all groups at comparable levels. On E7, ridge fusion in 13cisRA-treated embryos had not progressed as far proximally as in controls. By E8, there was a significant difference in the extent of fusion between 13cisRA-treated and non-RA-treated groups. We conclude 13cisRA-induced VSDs resulted from defective conotruncal ridge fusion and that the fusion defects did not result from decreased tissue volume, altered mesenchymal organization or increased necrosis.

Topics: Animals; Chick Embryo; Disease Models, Animal; Gestational Age; Heart Septal Defects; Isotretinoin

Among the findings associated with the human Retinoic Acid Embryopathy are hindbrain defects including the Arnold-Chiari malformation. The human Arnold-Chiari malformation (ACM) is a malformation complex where the cardinal feature is herniation of the caudal hindbrain into the vertebral column; it is frequently accompanied by lumbosacral myelorachischisis and hydrocephalus. Mice exposed to all-trans-retinoic acid or etretinate on day 8.25 of pregnancy, produce offspring with hindbrain herniation and caudal lumbosacral myelorachischisis in addition to a variety of other craniofacial and caudal malformations. Several experimental animals were observed to lack the caudal myelorachischisis proving that this lesion is not required to generate hindbrain herniation. We provide evidence that the cranial malformations, including hindbrain herniation, result from primary damage to the neural crest and the rhombencephalon. The vulnerability of these sites appears to be correlated with the presence of normal physiological cell death. While these experimental animals differ in many respects from the typical human Arnold-Chiari malformation, they may provide some insight into the pathogenesis of the latter.

Topics: Abnormalities, Drug-Induced; Animals; Disease Models, Animal; Ear; Exophthalmos; Female; Humans; Isotretinoin; Male; Mandible; Mice; Mice, Inbred C57BL; Neural Crest; Pregnancy; Rhombencephalon; Tretinoin

Dietary calcium glucarate (CGT) increased the activity of non-toxic levels of dietary isotretinoin against pre-established tumors in the chemically-induced rat mammary tumour model. In the range of 1.0-1.5 mmol/kg diet, isotretinoin enhanced tumour growth by 20% over a 4 week course of treatment. Tumour growth inhibition not exceeding 15% was observed only at dosages as high as 2.0 mmol/kg, i.e. in the cumulative toxicity range. Growth inhibition by 64 mmol/kg diet of CGT alone was marginal, varying from zero to 8%. In contrast, the combination of 1.0 mmol/kg of isotretinoin and 64 mmol/kg of CGT caused a reversible inhibition of tumour growth, culminating in a net decrease in tumour volume of 20%. This study documents the marginal enhancement of tumour growth by high sub-optimal concentrations of isotretinoin alone, and describes conditions for inhibition of tumour growth by sub-optimal concentrations of the natural retinoid. Related in vitro studies on retinoid sensitive and insensitive cell lines suggest that the anticancer activity of the combination is dependent on sensitivity of the cells to retinoids.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Division; Diet; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Resistance; Drug Synergism; Female; Fenretinide; Glucaric Acid; Isotretinoin; Mammary Neoplasms, Experimental; Rats; Rats, Inbred Strains; Tretinoin

Oral administration of 13-cis retinoic acid (RA) to pregnant mice on the 9th gestation day provokes important malformations of the middle ear ossicles, associated with a general kind of craniofacial dysmorphogenesis evoking the human mandibulofacial dysostosis. The malleus, incus and stapes are affected. The malleus exhibits a handle separated from its head and keeping a persistant relationship with the tubotympanic recess. The stapes makes no contact with the otic capsule. The malformation pattern is visible early as shown by the appearance of an abnormally curved Meckel's cartilage at day 12, followed by the development of atypically shaped ossicular anlagen. The mouse "far" (first arch malformation) mutation is responsible for minor ossicular abnormalities which disrupts the normal relationships between the stapes, Reichert's cartilage and stapedial muscle. The administration of RA to pregnant mice and the comparison with a genetically induced malformation (the mutation far) provides some interesting information about the postulated mechanisms of human middle ear dysmorphogenesis, as well as precious data about the features of normal ossicular primordia formation. The comparison of these features with human middle ear abnormalities as revealed by medical imaging sheds light on human malformation patterns and provides a better understanding of normal and abnormal radiologic ossicular aspects.

Topics: Abnormalities, Drug-Induced; Animals; Disease Models, Animal; Ear Ossicles; Humans; Isotretinoin; Mice; Mice, Inbred C57BL; Mice, Mutant Strains

Acute exposure to 400 mg/kg 13-cis retinoic acid (13-cis RA, isotretinoin, Accutane) on the ninth day postfertilization in mice (a time that corresponds to the fourth week postfertilization in humans) results in malformations that characterize mandibulofacial dysostosis (MFD, Treacher Collins syndrome). Deficiencies in the infraorbital region and in the mandibular ramus and condyle, abnormalities of the secondary palate, and external ear malformations were observed. Light and scanning electron microscopic analyses of affected embryos illustrate that within 12 hours of maternal 13-cis RA treatment, markedly excessive (possibly premature) cell death occurs in regions where some of the cells are normally destined to undergo programmed cell death. Previous studies with retinoids have shown that they labilize lysosomal membranes and expand and strengthen regions of programmed cell death. Of particular interest for this study was cell death occurring in the dorsal (proximal) aspects of the maxillary and mandibular prominences of the first visceral arch, the second visceral arch, and the first visceral cleft, areas that correspond to the locations of the first and second arch ectodermal ("ganglionic") placodes and first closing membrane, respectively. The derivatives of this region are those that are severely affected in MFD. As described in previous reports from this laboratory, 13-cis RA is known to interfere with neural crest cells, resulting in major craniofacial malformations. However, the exposure times involved were earlier than those described herein. It is hypothesized that effects on the first and second arch ectodermal placodal cells at a time following the release from the neural folds of neural crest cells into the developing cranial region are of great significance in the pathogenesis of MFD. This is in contrast to the prevailing hypothesis that these malformations are the direct result of a primary interference with neural crest cells.

Topics: Animals; Cell Survival; Disease Models, Animal; Female; Isotretinoin; Mandibulofacial Dysostosis; Mice; Mice, Inbred C57BL; Tretinoin