Search

Cerebrospinal fluid (CSF) leakage is considered the cause of spontaneous intracranial hypotension (SIH), an important etiology for new daily persistent headaches and a potentially life-threatening condition. Minor traumatic events rarely lead to CSF leakage, contrasting with iatrogenic interventions such as a lumbar puncture or spinal surgery, which are commonly complicated by dural tears. Most meningeal lesions are found in the cervicothoracic region, followed by the thoracic region, and rarely in the lumbar region, and extremely rarely in the sacral region. We describe two patients admitted to our hospital for severe headaches aggravated in the orthostatic position, with a recent history of minor trauma and sustained physical effort, respectively. In the first case, a bone fragment pierced an incidental congenital meningocele creating a dural fistula. An extensive extradural CSF collection, spanning the cervicothoracic region (C4–T10), was described in the second case. In both patients, the clinical evolution was favorable under conservative treatment.

The apicomplexan parasite Neospora caninum is an important causative agent of congenital neosporosis, resulting in abortion, birth of weak offspring and neuromuscular disorders in cattle, sheep, and many other species. Among several compound classes that are currently being developed, two have been reported to limit the effects of congenital neosporosis: (i) bumped kinase inhibitors (BKIs) target calcium dependent protein kinase 1 (CDPK1), an enzyme that is encoded by an apicoplast-derived gene and found only in apicomplexans and plants. CDPK1 is essential for host cell invasion and egress; (ii) endochin-like quinolones (ELQs) are inhibitors of the cytochrome bc1 complex of the mitochondrial electron transport chain and thus inhibit oxidative phosphorylation. We here report on the in vitro and in vivo activities of BKI-1748, and of ELQ-316 and its respective prodrugs ELQ-334 and ELQ-422, applied either as single-compounds or ELQ-BKI-combinations. In vitro, BKI-1748 and ELQ-316, as well as BKI-1748 and ELQ-334, acted synergistically, while this was not observed for the BKI-1748/ELQ-422 combination treatment. In a N. caninum-infected pregnant BALB/c mouse model, the synergistic effects observed in vitro were not entirely reproduced, but 100% postnatal survival and 100% inhibition of vertical transmission was noted in the group treated with the BKI-1748/ELQ-334 combination. In addition, the combined drug applications resulted in lower neonatal mortality compared to treatments with single drugs., Graphical abstract Image 1, Highlights • BKI-1748 is a bumped kinase inhibitor with anti-Neospora activity in vitro and in vivo • Endochin-like quinolones target the cytochrome bc1 complex and exhibit anti-Neospora properties. • Single and combined applications of these two compound classes do not interfere in pregnancy outcome in mice • BKI-1748/ELQ-334 combination treatment results in 100% postnatal survival and blocks vertical transmission in the neosporosis mouse model

Trithiolato-bridged dinuclear ruthenium(II)-arene complexes are active against various parasites including Toxoplasma gondii. Lipids, isoprenoids and lipoate are metabolites scavenged by T. gondii from the host cell but also synthesized by the parasite, and these molecules can be appended to the diruthenium moiety in a conjugate approach aiming at compounds with improved antiparasitic activity and selectivity. The synthesis and in vitro T. gondii activity evaluation of 23 new trithiolato diruthenium complexes bearing various lipophilic units are reported. The influence of several structural elements as the nature of the lipophilic pendant and the type of the connecting bond between the two units on the conjugates’ biological properties were examined. In a primary screening, the antiparasitic efficacy and cytotoxicity were assessed at 0.1 and 1 µM against transgenic T. gondii tachyzoites constitutively expressing β-galactosidase and on human foreskin fibroblasts (HFF) host cells. For 14 selected conjugates the half-maximal inhibitory concentration (IC50) on T. gondii and their effect on HFF viability at 2.5 µM were determined. The decanoic, oleic and elaidic ester conjugates 13a, 16a and 17a efficiently inhibited parasite proliferation (IC50 values of 0.065, 0.127 and 0.123 µM, respectively) with no effect on HFF viability at 2.5 µM and deserve further attention.

Eight novel carbohydrate-tethered trithiolato dinuclear ruthenium(II)-arene complexes were synthesized using CuAAC 'click' (Cu(I)-catalyzed azide-alkyne cycloaddition) reactions and, together with the diruthenium intermediates, were assessed for their in vitro activity against transgenic Toxoplasma gondii (T. gondii) tachyzoites constitutively expressing β-galactosidase (T. gondii β-gal), and for their cytotoxicity in non-infected host cells (human foreskin fibroblasts, HFFs). The results revealed that the biological activity of the hybrids was influenced by both the nature of the carbohydrate (glucose or galactose) attached to the ruthenium complex and the type/length of the linker between the two units. For seven selected diruthenium-carbohydrate conjugates, the values of the half-maximal inhibitory concentration (IC50) on T. gondii β-gal and HFFs viability for a compound concentration of 2.5 μM were measured. Remarkably, two galactose-diruthenium conjugates, 23 and 26, performed significantly better than the corresponding unlabeled diruthenium complexes and the standard drug Pyrimethamine, with very low IC50 values (23: IC50 = 0.032 μM, 26: IC50 = 0.153 μM, Pyrimethamine, IC50 = 0.326 μM) and a very low toxicity on HFFs (viability 92% for 23 and 97% for 26). Overall, our study shows that conjugation of carbohydrates to diruthenium compounds is a promising approach to develop new effective antiparasitic compounds with reduced toxicity.

The synthesis, photophysical properties and antiparasitic efficacy against Toxoplasma gondii β-gal (RH strain tachyzoites expressing β-galactosidase) grown in human foreskin fibroblast monolayers (HFF) of a series of 15 new conjugates BODIPY-trithiolato-bridged dinuclear ruthenium(II)-arene complexes are reported (BODIPY = 4,4-difluoro-4-bora-3a,4a-diaza- s -indacene, derivatives used as fluorescent markers). The influence of the bond type (amide vs ester), as well as that of the length and nature (alkyl vs aryl) of the spacer between the dye and the diruthenium(II) complex moiety, upon the fluorescence and the biological activity were evaluated. The assessed photophysical properties revealed that despite an important fluorescence quenching effect observed after conjugating the BODIPY to the diruthenium unit, the hybrids could nevertheless be used as fluorescent tracers. Although the antiparasitic activity of these series of conjugates appears limited, the compounds demonstrate potential as fluorescent probes to be used for investigating the intracellular trafficking of trithiolato-bridged dinuclear Ru(II)-arene complexes in vitro .

Graphical abstract, Introduction Obtaining a certain bone volume is an important goal in implantology or orthopedics. Thus, after tooth extraction, quite a lot of horizontal and vertical alveolar bone is lost in time and can be detrimental to the implant treatment outcome, while the treatment of critical bone defects is a considerable challenge for surgery. Objectives In this study we designed a new in vivo model as an useful experimental tool to assess guided bone regeneration (GBR) using a computer-aided design/manufacturing (CAD-CAM) space-maintaining barrier. Methods The barrier was 3D printed with three progressive heights, surgically placed on rat femur, and GBR results were analyzed at 2, 4, and 8 weeks by X-ray and bone mineral density analysis, histology/morphometry and by immunofluorescence and immunohistochemistry for osteogenesis and angiogenesis evaluation. Results The obtained results show that the proposed experimental model provides a real-time useful information on progressive bone tissue formation, which depends on the volume of isolated space created for GBR and on molecular events that lead to satisfactory vertical and horizontal bone augmentation and osteointegration. Conclusion In conclusion, the proposed customized three-dome space-maintaining barrier is suitable as an experimental tool to assess the potential of using the designed barriers in dentistry and orthopedics to promote the formation of new bone and determine their space- and time-dependent limitations. Meanwhile, guided bone augmentation for dentistry requires subsequent evaluation on an alveolar bone preclinical model followed by clinical implementation.

Neospora caninum is an apicomplexan parasite closely related to Toxoplasma gondii, and causes abortions, stillbirths and/or fetal malformations in livestock. Target-based drug development has led to the synthesis of calcium-dependent protein kinase 1 inhibitors, collectively named bumped kinase inhibitors (BKIs). Previous studies have shown that several BKIs have excellent efficacy against neosporosis in vitro and in vivo. However, several members of this class of compounds impair fertility in pregnant mouse models and cause embryonic malformation in a zebrafish (Danio rerio) model. Similar to the first-generation antiprotozoal drug quinine, some BKIs have a quinoline core structure. To identify common targets in both organisms, we performed differential affinity chromatography with cell-free extracts from N. caninum tachyzoites and D. rerio embryos using the 5-aminopyrazole-4-carboxamide (AC) compound BKI-1748 and quinine columns coupled to epoxy-activated sepharose followed by mass spectrometry. BKI-binding proteins of interest were identified in eluates from columns coupled to BKI-1748, or in eluates from BKI-1748 as well as quinine columns. In N. caninum, 12 proteins were bound specifically to BKI-1748 alone, and 105 proteins, including NcCDPK1, were bound to both BKI-1748 and quinine. For D. rerio, the corresponding numbers were 13 and 98 binding proteins, respectively. In both organisms, a majority of BKI-1748 binding proteins was involved in RNA binding and modification, in particular, splicing. Moreover, both datasets contained proteins involved in DNA binding or modification and key steps of intermediate metabolism. These results suggest that BKI-1748 interacts with not only specific targets in apicomplexans, such as CDPK1, but also with targets in other eukaryotes, which are involved in common, essential pathways.

The synthesis, characterization, photophysical and biological properties of 13 new conjugate coumarin‐diruthenium(II)⋅arene complexes against Toxoplasma gondii are presented. For all conjugate organometallic unit/coumarins, an almost complete loss of fluorescence efficacy was observed. However, the nature of the fluorophore, the type of bonding, the presence and length of a linker between the coumarin dye and the ruthenium(II) moiety, and the number of dye units influenced their biological properties. The in vitro activity against a transgenic T. gondii strain grown in human foreskin fibroblasts (HFF) leads to IC50 values for T. gondii β‐gal from 105 to 735 nM. Of note is that nine compounds displayed lower IC50 than the standard drug pyrimethamine. One compound applied at its IC50 did not affect B‐cell proliferation but had an impact on T‐cell proliferation in murine splenocyte cultures. Transmission electron microscopy of T. gondii β‐gal‐infected HFF showed that treatment predominantly affected the parasites’ mitochondrion., The (para)site for treatment: Thirteen coumarin‐diruthenium(II)⋅arene conjugates were evaluated against a transgenic T. gondii strain grown in human foreskin fibroblasts (HFF). The IC50 values ranged from 105 to 735 nM, with nine compounds displaying a lower IC50 than the standard drug pyrimethamine. TEM of T. gondii‐infected HFF showed that treatment predominantly affected the parasites’ mitochondrion.

Patient: Female, 54-year-old Final Diagnosis: Zoster cranial polyneuropathy Symptoms: Diplopia • facial palsy • hypoacusis • nausea • nystagmus • tinnitus • vertigo • vomiting • zoster rash Medication: — Clinical Procedure: — Specialty: Infectious Diseases • Neurology Objective: Rare disease Background: Ramsay Hunt syndrome is a rare form of herpes zoster caused by the reactivation of the varicella-zoster virus in the geniculate ganglion. The main clinical manifestations are peripheral facial palsy, vesicular rash in the ear, and ipsilateral auricular pain, and sometimes vertigo. COVID-19 is a new multisystemic infectious disease that, in addition to common respiratory manifestations, it is known to affect the immune system, primarily depressing cellular immunity. Case Report: A 54-year-old woman was admitted to our hospital with an acute vestibular syndrome and diplopia. She had been diagnosed 3 years prior with interstitial lung disease for which she was taking methylprednisolone. At admission, she tested positive for SARS-CoV-2. In the following days, she developed a sixth nerve palsy on the left side and a right peripheral facial palsy on the right side, followed by a typical zoster rash on the ipsilateral ear. One month later, she developed acute severe hearing loss on the right side. There were no COVID-19 symptoms during her stay in our hospital. The MRI showed Gd enhancement of both facial nerves. Under antiviral and corticoid treatment, the evolution was favorable, with marked improvement at 6 months. Conclusions: COVID-19 increases the risk for herpes zoster infection, probably through induced depression of the cellular immunity. Our case suggests Ramsay Hunt syndrome can be the presenting symptom and sometimes the only symptom of COVID-19. This also seems to be true for other cranial neuropathies, and we recommend testing these patients even if there are no other manifestations.

The quinolone decoquinate (DCQ) is widely used in veterinary practice for the treatment of bacte-rial and parasitic infections, most notably coccidiosis in poultry and in ruminants. We have in-vestigated the effects of treatment of Toxoplasma gondii in infected human foreskin fibroblasts (HFF) with DCQ. It induced distinct alterations in the parasite mitochondrion within 24h, which persisted even after long-term (500 nM, 52 days) treatment, although there was no parasiticidal effect. Based on the low half-maximal effective concentration (IC50) of 1.1 nM and the high selec-tivity index of >5000, the efficacy of oral treatment of pregnant mice experimentally infected with T. gondii oocysts with DCQ at 10 mg/kg/day for 5 days was assessed. However, the treatment had detrimental effects, induced higher neonatal mortality than T. gondii infection alone, and did not prevent vertical transmission. Thus, three quinoline-O-carbamate derivatives of DCQ antici-pated to have better physicochemical properties than DCQ were assessed in vitro. One such com-pound RMB060 displayed an exceedingly low IC50 of 0.07 nM when applied concomitantly with infection of host cells and had no impact on HFF viability at 10 µM. As was the case for DCQ, RMB060 treatment resulted in alteration of the mitochondrial matrix and loss of cristae, but the changes became apparent at just 6h after commencement of treatment. After 48h, RMB060 induced the expression of the bradyzoite antigen BAG1, but TEM did not reveal any other features remi-niscent of bradyzoites. Exposure of infected cultures to 300 nM RMB060 for 52 days did not re-sult in complete killing of all tachyzoites, although mitochondria remained ultrastructurally damaged and there was a slower proliferation rate. Treatment of mice infected with T. gondii oocysts with RMB060 did reduce parasite burden in non-pregnant mice and dams, but vertical transmission to pups could not be prevented.

A structure activity relationship (SAR) study of a library of 56 compounds (54 ruthenium and 2 osmium derivatives) based on the trithiolato-bridged dinuclear ruthenium(II)-arene scaffold (general formula [(η6-arene)2Ru2(μ2-SR)3]+, symmetric and [(η6-arene)2Ru2(μ2-SR1)2(μ2-SR2)]+, mixed, respectively) is reported. The 56 compounds (of which 34 are newly designed drug candidates) were synthesized by introducing chemical modifications at the level of bridge thiols, and they were grouped into eight families according to their structural features. The selected fittings were guided by previous results and focused on a fine-tuning of the physico-chemical and steric properties. Newly synthesized complexes were characterized by NMR spectroscopy, mass spectrometry and elemental analysis, and four single-crystal X-ray structures were obtained. The in vitro biological assessment of the compounds was realized by applying a three-step screening cascade: (i) evaluation of the activity against Toxoplasma gondii RH strain tachyzoites expressing β-galactosidase (T. gondii-β-gal) grown in human foreskin fibroblast monolayers (HFF) and assessment of toxicity in non-infected HFF host cells; (ii) dose-response assays using selected compound, and (iii) studies on the effects in murine splenocytes. A primary screening was performed at 1 and 0.1 μM, and resulted in the selection of 39 compounds that inhibited parasite proliferation at 1 μM by more than 95% and reduced the viability of HFF by less than 49%. In the secondary screening, dose-response assays showed that the selected compounds exhibited half maximal inhibitory concentration (IC50) values for T. gondii-β-gal between 0.01 μM and 0.45 μM, with 30 compounds displaying an IC50 lower than 0.1 μM. When applied to non-infected HFF monolayers at 2.5 μM, 8 compounds caused more than 90% and 31 compounds more than 30% viability impairment. The tertiary screening included 14 compounds that did not cause HFF viability loss higher than 50% at 2.5 μM. These derivatives were assessed for potential immunosuppressive activities. First, splenocyte viability was assessed after treatment of cells with concanavalin A (ConA) and lipopolysaccharide (LPS) with compounds applied at 0.1 and 0.5 μM. Subsequently, the 5 compounds exhibiting the lowest splenocyte toxicity were further evaluated for their potential to inhibit B and T cell proliferation. Overall, compound 55 [(η6-p-MeC6H4Pri)2Ru2(μ2-SC6H4-o-CF3)2(μ2-SC6H4-p-OH)]Cl exhibited the most favorable features, and will be investigated as a scaffold for further optimization in terms of anti-parasitic efficacy and drug-like properties

The synthesis, characterization, and in vitro antiparasitic and anticancer activity evaluation of new conjugates containing two and three dinuclear trithiolato-bridged ruthenium(II)-arene units are presented. Antiparasitic activity was evaluated using transgenic Toxoplasmagondii tachyzoites constitutively expressing &beta, galactosidase grown in human foreskin fibroblasts (HFF). The compounds inhibited T.gondii proliferation with IC50 values ranging from 90 to 539 nM, and seven derivatives displayed IC50 values lower than the reference compound pyrimethamine, which is currently used for treatment of toxoplasmosis. Overall, compound flexibility and size impacted on the anti-Toxoplasma activity. The anticancer activity of 14 compounds was assessed against cancer cell lines A2780, A2780cisR (human ovarian cisplatin sensitive and resistant), A24, (D-)A24cisPt8.0 (human lung adenocarcinoma cells wild type and cisPt resistant subline). The compounds displayed IC50 values ranging from 23 to 650 nM. In A2780cisR, A24 and (D-)A24cisPt8.0 cells, all compounds were considerably more cytotoxic than cisplatin, with IC50 values lower by two orders of magnitude. Irrespective of the nature of the connectors (alkyl/aryl) or the numbers of the di-ruthenium units (two/three), ester conjugates 6&ndash, 10 and 20 exhibited similar antiproliferative profiles, and were more cytotoxic than amide analogues 11&ndash, 14, 23, and 24. Polynuclear conjugates with multiple trithiolato-bridged di-ruthenium(II)-arene moieties deserve further investigation.

Cavernomas are rare cerebrovascular malformations that usually occur in sporadic forms with solitary lesions located most often in the hemispheric white matter, but also in the infratentorial or spinal region. Multiple lesions at different CNS levels are considered a hallmark for the familial form of the disease. The diagnostic modality of choice for cerebral cavernous malformations (CCMs) is magnetic resonance imaging (MRI). We present an intriguing case of a 65-year-old male admitted to our hospital with tetraparesis and cognitive impairment where highly sensitive MRI sequences identified many cerebral cavernous lesions at the supra-, infratentorial and cervical–thoracic spine levels, some of them with recent signs of bleeding in a patient with oral anticoagulant therapy due to atrial fibrillation. The mechanism of cognitive impairment in this patient is most probably the interruption of strategic white matter tracts, as it is known to happen in other subcortical vascular pathologies. MRI can be helpful not only in mapping the anatomical distribution of lesions, but also in weighing the risks and making decisions regarding whether or not to continue oral anticoagulant therapy.

This is a review of the development of bumped-kinase inhibitors (BKIs) for the therapy of One Health parasitic apicomplexan diseases. Many apicomplexan infections are shared between humans and livestock, such as cryptosporidiosis and toxoplasmosis, as well as livestock only diseases such as neosporosis. We have demonstrated proof-of-concept for BKI therapy in livestock models of cryptosporidiosis (newborn calves infected with Cryptosporidium parvum), toxoplasmosis (pregnant sheep infected with Toxoplasma gondii), and neosporosis (pregnant sheep infected with Neospora caninum). We discuss the potential uses of BKIs for the treatment of diseases caused by apicomplexan parasites in animals and humans, and the improvements that need to be made to further develop BKIs.

Bumped kinase inhibitors (BKIs) are effective against a variety of apicomplexan parasites. Fifteen BKIs with promising in vitro efficacy against Neospora caninum tachyzoites, low cytotoxicity in mammalian cells, and no toxic effects in non-pregnant BALB/c mice, were assessed in pregnant mice. Drugs were emulsified in corn oil and applied by gavage for 5 days. Five BKIs did not affect pregnancy, 5 BKIs exhibited 15-35% of neonatal mortality, and 5 compounds caused strong effects (infertility, abortion, stillbirth and pup mortality). Additionally, the impact of these compounds on zebrafish (Danio rerio) embryo development was assessed by exposing freshly fertilized eggs to 0.2-50μM of BKIs and microscopical monitoring of embryo development in a blinded manner during 4 days. We propose an algorithm that includes quantification of malformations and embryo deaths, and established a scoring system that allows to calculate an impact score (Si) that indicates at which concentrations BKIs visibly affect zebrafish embryo development. Comparison of the two models showed that for 9 compounds no clear correlation between Si and pregnancy outcome was visible. However, those 3 BKIs affecting zebrafish embryos only at high concentrations (40μM or higher) did not impair mouse pregnancy at all, and those 3 compounds that inhibited zebrafish embryo development already at 0.2μM showed detrimental effects in the pregnancy model. Thus, the zebrafish embryo development test has a limited predictive value to foresee pregnancy outcome in BKI-treated mice. We conclude, that maternal health-related factors such as cardiovascular, pharmacokinetic and/or bioavailability properties also contribute to BKI-pregnancy effects.

Helminthiases, a group of neglected tropical diseases, affect more than one billion people mainly in tropical and subtropical regions. Albendazole (ABZ) is a broad‐spectrum anthelmintic recommended by the World Health Organisation (WHO). However, drug resistance is emerging due to its widespread use. In order to tackle this problem, taking into account the spectacular results obtained with the organometallic derivatization of the antimalarial drug chloroquine, we have prepared, in this study, a series of new ferrocenyl and ruthenocenyl derivatives of the organic drug ABZ and assessed their activity against different helminths but also protozoans, namely Trichuris muris adult, Heligmosomoides polygygrus adult, Schistosoma mansoni adult, Giardia lamblia, Haemonchus contortus xL3s and Toxoplasma gondii to determine the full potential of our new compounds. Worthy of note, the ferrocene‐containing ABZ analogue 2d exhibited over 70% activity against T. muris adult in vitro and no toxicity to mammalian cells up to 100 µM. Against T. gondii, the ferrocene‐containing ABZ analogues 1a and 2d showed better in vitro activity than ABZ and low toxicity to the host cells. However, the activity of the analogous ruthenocenyl compound 2b against S. mansoni and T. gondii in vitro could rather be attributed to its toxicity towards the host cells rather than a specific antiparasitic activity. These results demonstrate that the choice of the organometallic moieties attached to the organic drug is playing a very important role. Two of our organometallic compounds, namely 1b and 2d, were tested in T. muris infected mice. At a 400 mg/kg dose, the compounds showed moderate worm burden reductions and low worm expulsion rates. Overall, this work, which is one of the first studies reporting the potential of organometallic compounds on a very broad range of parasitic helminths and protozoan, is a clear confirmation of the potential of organometallic complexes against parasites of medical and veterinary importance.

International audience; Helminthiases, a group of neglected tropical diseases, affect more than one billion people mainly in tropical and subtropical regions. Moreover, major intestinal protozoa have a significant impact on global public health. Albendazole (ABZ) is a broad-spectrum anthelmintic recommended by the World Health Organisation (WHO). However, drug resistance is emerging due to its widespread use. In order to tackle this problem, taking into account the spectacular results obtained with the organometallic derivatization of the antimalarial drug chloroquine, we have prepared, in this study, a series of new ferrocenyl and ruthenocenyl derivatives of the organic drug ABZ and assessed their activity against different helminths and protozoans, namely Trichuris muris, Heligmosomoides polygygrus, Schistosoma mansoni, Giardia lamblia, Haemonchus contortus and Toxoplasma gondii. The ferrocene-containing ABZ analogue 2d exhibited over 70% activity against T. muris adults in vitro at 200 µM and no toxicity to mammalian cells (IC50> 100 µM). H. polygyrus adults were not affected by any of the derivatives tested. Against T. gondii, the ferrocene-containing ABZ analogues 1a and 2d showed better in vitro activity than ABZ and low toxicity to the host cells. The activity of the analogous ruthenocenyl compound 2b against S. mansoni and T. gondii in vitro might be attributed to its toxicity towards the host cells rather than a specific antiparasitic activity. These results demonstrate that the derivatives show a species specific in vitro activity and the choice of the organometallic moieties attached to the organic drug is playing a very important role. Two of our organometallic compounds, namely 1b and 2d, were tested in T. muris infected mice. At a 400 mg/kg dose, the compounds showed moderate worm burden reductions but low worm expulsion rates. Overall, this work, which is one of the first studies reporting the potential of organometallic compounds on a very broad range of parasitic helminths and protozoan, is a clear confirmation of the potential of organometallic complexes against parasites of medical and veterinary importance.

Tethering known drugs to a metalorganic moiety is an efficient approach for modulating the anticancer, antibacterial, and antiparasitic activity of organometallic complexes. This study focused on the synthesis and evaluation of new dinuclear ruthenium(II)–arene compounds linked to several antimicrobial compounds such as dapsone, sulfamethoxazole, sulfadiazine, sulfadoxine, triclosan, metronidazole, ciprofloxacin, as well as menadione (a 1,4-naphtoquinone derivative). In a primary screen, 30 compounds (17 hybrid molecules, diruthenium intermediates, and antimicrobials) were assessed for in vitro activity against transgenic T.&nbsp, gondii tachyzoites constitutively expressing β-galactosidase (T.&nbsp, gondii β-gal) at 0.1 and 1 µM. In parallel, the cytotoxicity in noninfected host cells (human foreskin fibroblasts, HFF) was determined by an alamarBlue assay. When assessed at 1 µM, five compounds strongly impaired parasite proliferation by &gt, 90%, and HFF viability was retained at 50% or more, and they were further subjected to T.&nbsp, gondii β-gal dose-response studies. Two compounds, notably 11 and 13, amide and ester conjugates with sulfadoxine and metronidazole, exhibited low IC50 (half-maximal inhibitory concentration) values 0.063 and 0.152 µM, and low or intermediate impairment of HFF viability at 2.5 µM (83 and 64%). The nature of the anchored drug as well as that of the linking unit impacted the biological activity.

A library of 18 dinuclear-thiolato bridged arene ruthenium complexes, some of which with demonstrated activity against cancer cells, was screened for activity against a transgenic Neospora caninum strain that constitutively expresses beta-galactosidase. Initial assessments were done at concentrations of 2500, 250, 25 and 2.5 nM, and 5 compounds were further evaluated with regard to their half maximal proliferation-inhibiting concentration (IC50). Among those, [(η6-p-MeC6H4Pri)2Ru2(μ2-SC6H4-p-CH3)3]Cl (1), [(η6-p-MeC6H4Pri)2Ru2(μ2-SC6H4-p-But)3]Cl (2) and [(η6-p-MeC6H4Pri)2Ru2(μ2-SCH2C6H4-p-But)2(μ2-SC6H4-p-OH)]BF4 (9) inhibited N. caninum proliferation with low C50 values of 15, 5 and 1 nM, respectively, while [(η6-p-MeC6H4Pri)2Ru2(μ2-SC6H4-p-OH)3]Cl (3) and [(η6-p-MeC6H4Pri)2Ru2(μ2-SC6H4-p-mco)3]Cl (5, mco = 4-methylcoumarinyl) were less active (IC50 = 280 and 108 nM, respectively). These compounds did not affect human foreskin fibroblast (HFF) host cells at dosages of 5 μM and above, but impaired proliferation of the human ovarian carcinoma cell line A2780 (IC50 values of 130 nM (1), 30 nM (2), 530 nM (3), 7730 nM (5), 130 nM (9)). A2780 cancer cells were treated with complexes 1, 2, and 5, and biodistribution analysis using inductively coupled plasma mass spectrometry (ICP-MS) showed that most of the drugs accumulated in the mitochondrial fractions. Transmission electron microscopy showed that the parasite mitochondrion is the primary target also in N. caninum tachyzoites, but these compounds, when applied at 200 nM for 15 days in vitro, did not act parasiticidal. Complexes 1, 2 and 9 applied orally at 2 and 10 mg kg−1 day−1 during 5 days in a neosporosis mouse model did not reduce parasite load and did not limit parasite dissemination to the central nervous system. In accordance with these results, ICP-MS carried out on different organs of mice orally administrated with complexes 1 and 9, demonstrated that the drugs were readily absorbed, and after 3 and 48 h, were mainly detected in liver and kidney, but were largely absent from the brain. Thus, dinuclear thiolato-bridged arene ruthenium complexes exhibit interesting activities against N. caninum in vitro, but further modifications of these promising molecules are required to improve their bioavailability and pharmacokinetic properties in order to exert a pronounced and selective effect against N. caninum in vivo.

We report on the efficacy of selected endochin-like quinolones (ELQs) against N. caninum tachyzoites grown in human foreskin fibroblasts (HFF), and in a pregnant BALB/c mouse model. Fourteen ELQs were screened against transgenic N. caninum tachyzoites expressing β-galactosidase (Nc-βgal). Drugs were added concomitantly to infection and the values for 50% proliferation inhibition (IC50) were determined after 3 days. Three compounds exhibited IC50 values below 0.1 nM, 3 ELQs had IC50s between 0.1 and 1 nM, for 7 compounds values between 1 and 10 nM were noted, and one compound had an IC50 of 22.4 nM. Two compounds, namely ELQ-316 and its prodrug ELQ-334 with IC50s of 0.66 and 3.33 nM, respectively, were previously shown to display promising activities against experimental toxoplasmosis and babesiosis caused by Babesia microti in mice, and were thus further studied. They were assessed in long-term treatment assays by exposure of infected HFF to ELQs at 0.5 μM concentration, starting 3 h after infection and lasting for up to 17 days followed by release of drug pressure. Results showed that the compounds substantially delayed parasite proliferation, but did not exert parasiticidal activities. TEM of drug treated parasites detected distinct alterations within the parasite mitochondria, but not in other parasite organelles. Assessment of safety of ELQ-334 in the pregnant mouse model showed that the compound did not interfere in fertility or pregnancy outcome. In N. caninum infected pregnant mice treated with ELQ-334 at 10 mg/kg/day for 5 days, neonatal mortality (within 2 days post partum) was found in 7 of 44 pups (15.9%), but no postnatal mortality was noted, and vertical transmission was reduced by 49% compared to the placebo group, which exhibited 100% vertical transmission, neonatal mortality in 15 of 34 pups (44%), and postnatal mortality for 18 of the residual 19 pups during the 4 weeks follow-up. These findings encourage more research on the use of ELQs for therapeutic options against N. caninum infection.

Mucositis is a serious disorder of the gastrointestinal tract that results from cancer chemotherapy. We investigated the protective effects of silymarin on epirubicin-induced mucosal barrier injury in CD-1 mice. Immunohistochemical activity of both pro-apoptotic Bax and anti-apoptotic Bcl-2 markers, together with p53, cyt-P450 expression and DNA damage analysis on stomach, small intestine and colon were evaluated. Our results indicated stronger expression for cyt P450 in all analyzed gastrointestinal tissues of Epi group, which demonstrate intense drug detoxification. Bax immunopositivity was intense in the absorptive enterocytes and lamina connective cells of the small intestine, surface epithelial cells of the stomach and also in the colonic epithelium and lamina concomitant with a decreased Bcl-2 expression in all analyzed tissues. Epirubicin-induced gastrointestinal damage was verified by a goblet cell count and morphology analysis on histopathological sections stained for mucins. In all analyzed tissues, Bax immunopositivity has been withdrawn by highest dose of silymarin concomitant with reversal of Bcl-2 intensity at a level comparable with control. p53 expression was found in all analyzed tissues and decreased by high dose of silymarin. Also, DNA internucleosomal fragmentation was observed in the Epi groups for all analyzed tissues was almost suppressed at 100 mg/kg Sy co-treatment. Histological aspect and goblet cell count were restored at a highest dose of Sy for both small and large intestine. In conclusion, our findings suggest that silymarin may prevent cellular damage of epirubicin-induced toxicity and was effective in reducing the severity indicators of gastrointestinal mucositis in mice.