Topical Administration of a Nanoformulation of Chitosan-Hyaluronic Acid-Epoetin Beta in a Rat Model of Glaucoma.

The present work investigates the effects of chitosan-hyaluronic acid-epoetin beta (CS/HA-EPOß) nanoparticles after topical ocular administration in a rat glaucoma model. Wistar Hannover rats (n = 24) were submitted to a complete ophthalmological examination and electroretinography, followed by glaucoma induction in their right eye on day 1 of the study. Treatment group (T) received CS/HA-EPOß nanocarriers (n = 12), while the control group (C) received only empty ones. Electroretinography was repeated on day 3 (n = 24) and before euthanasia on day 7 (n = 8), 14 (n = 8), and 21 (n = 8), followed by bilateral enucleation and histological assessment. The animals showed good tolerance to the nanoformulation. Maximum IOP values on the right eye occurred shortly after glaucoma induction (T = 62.6 ± 8.3 mmHg; C = 63.6 ± 7.9 mmHg). Animals from the treated group presented a tendency for faster recovery of retinal electrical activity (p > 0.05). EPOß was detected on the retina of all treated eyes using immunofluorescence. Control animals presented with thinner retinas compared to the treated ones (p < 0.05). Therefore, topical ocular administration of CS/HA-EPOß nanoparticles enabled EPOß delivery to the retina of glaucomatous rats and promoted an earlier retinal recovery, confirming EPOß's neuroprotective effects. The encouraging results of this preclinical study pave the way for new strategies for topical ocular administration of neuroprotective compounds.

Vernonia britteniana Root Phytochemical Studies, In Vitro Cercaricidal Activity on the Larval Stage of Schistosoma mansoni and Antioxidant Activities.

Vernonia britteniana Hiern. (Asteraceae) is a medicinal plant used in traditional Angolan medicine against schistosomiasis. Our study aimed to investigate the phytochemical composition and the cercaricidal and antioxidant activities in vitro of a traditional herbal preparation (Water-Vbr) and a 70% hydroethanolic extract (EtOH70%-Vbr) prepared with this medicinal plant. The activity of the extracts against Schistosoma mansoni cercariae was assessed at different extract concentrations (500, 438, and 125 µg/mL) and at different time intervals, and the phytochemical profiles were obtained by LC-UV-ESI/MS-MS. In addition, the major chemical classes of the identified metabolites were quantified by colorimetry, and the antioxidant potential was assessed using the DPPH and FRAP methods. After 30 min, 100% cercarial mortality was observed at a concentration of 500 µg/mL after exposure, and after 120 min, an LC50 of 438 µg/mL was observed for both extracts. Phenolic acid derivatives (chlorogenic acid, caffeic acid; 3,4-di-O-caffeoylquinic acid; 3,5-di-O-caffeoylquinic acid; and 4,5-di-O-caffeoylquinic acid) and triterpenoids (stigmastane-type steroidal saponins; vernoamyoside D and vernonioside D1; vernoamyoside B; and vernoniamyoside A and C) were identified as the main secondary metabolites. The Water-Vbr extract showed the highest antioxidant activity-DPPH: IC50 = 1.769 ± 0.049 µg/mL; FRAP: mean = 320.80 ± 5.1325 µgAAE/g.

Rabbit derived VL single-domains as promising scaffolds to generate antibody-drug conjugates.

Antibody-drug conjugates (ADCs) are among the fastest-growing classes of therapeutics in oncology. Although ADCs are in the spotlight, they still present significant engineering challenges. Therefore, there is an urgent need to develop more stable and effective ADCs. Most rabbit light chains have an extra disulfide bridge, that links the variable and constant domains, between Cys80 and Cys171, which is not found in the human or mouse. Thus, to develop a new generation of ADCs, we explored the potential of rabbit-derived VL-single-domain antibody scaffolds (sdAbs) to selectively conjugate a payload to Cys80. Hence, a rabbit sdAb library directed towards canine non-Hodgkin lymphoma (cNHL) was subjected to in vitro and in vivo phage display. This allowed the identification of several highly specific VL-sdAbs, including C5, which specifically target cNHL cells in vitro and present promising in vivo tumor uptake. C5 was selected for SN-38 site-selective payload conjugation through its exposed free Cys80 to generate a stable and homogenous C5-DAB-SN-38. C5-DAB-SN-38 exhibited potent cytotoxicity activity against cNHL cells while inhibiting DNA-TopoI activity. Overall, our strategy validates a platform to develop a novel class of ADCs that combines the benefits of rabbit VL-sdAb scaffolds and the canine lymphoma model as a powerful framework for clinically translation of novel therapeutics for cancer.

Chitosan and Hyaluronic Acid Nanoparticles as Vehicles of Epoetin Beta for Subconjunctival Ocular Delivery.

Neuroprotection in glaucoma using epoetin beta (EPOß) has yielded promising results. Our team has developed chitosan-hyaluronic acid nanoparticles (CS/HA) designed to carry EPOß into the ocular globe, improving the drug's mucoadhesion and retention time on the ocular surface to increase its bioavailability. In the present in vivo study, we explored the possibility of delivering EPOß to the eye through subconjunctival administration of chitosan-hyaluronic acid-EPOß (CS/HA-EPOß) nanoparticles. Healthy Wistar Hannover rats (n = 21) were split into 7 groups and underwent complete ophthalmological examinations, including electroretinography and microhematocrit evaluations before and after the subconjunctival administrations. CS/HA-EPOß nanoparticles were administered to the right eye (OD), and the contralateral eye (OS) served as control. At selected timepoints, animals from each group (n = 3) were euthanized, and both eyes were enucleated for histological evaluation (immunofluorescence and HE). No adverse ocular signs, no changes in the microhematocrits (≈45%), and no deviations in the electroretinographies in both photopic and scotopic exams were observed after the administrations (p < 0.05). Intraocular pressure remained in the physiological range during the assays (11-22 mmHg). EPOß was detected in the retina by immunofluorescence 12 h after the subconjunctival administration and remained detectable until day 21. We concluded that CS/HA nanoparticles could efficiently deliver EPOß into the retina, and this alternative was considered biologically safe. This nanoformulation could be a promising tool for treating retinopathies, namely optic nerve degeneration associated with glaucoma.

Polyphasic Validation of a Nisin-Biogel to Control Canine Periodontal Disease.

BACKGROUND: Periodontal disease (PD) is a highly prevalent inflammatory disease in dogs. This disease is initiated by a polymicrobial biofilm on the teeth surface, whose control includes its prevention and removal. Recently, it was shown that nisin displays antimicrobial activity against canine PD-related bacteria. Moreover, guar gum biogel has shown to be a promising topical delivery system for nisin. METHODS: In this study we aimed to evaluate the antimicrobial activity of the nisin-biogel in the presence of canine saliva and after a 24-month storage, at different conditions, using a canine oral enterococci collection. We also studied the nisin-biogel cytotoxicity using a Vero cell line and canine primary intestinal fibroblasts. RESULTS: The presence of saliva hampers nisin-biogel antimicrobial activity, and higher nisin concentrations were required for an effective activity. A significant reduction (p ≤ 0.05) in inhibitory activity was observed for nisin-biogel solutions stored at 37 °C, over a 24-month period, which was not observed with the other conditions. The nisin-biogel showed no cytotoxicity against the cells tested at concentrations up to 200 µg/mL. CONCLUSIONS: Our results confirmed the potential of the nisin-biogel for canine PD control, supporting the development of an in vivo clinical trial.

New nanoparticles for topical ocular delivery of erythropoietin.

Erythropoietin (EPO) is known for its neuroprotective and neuroregenerative properties. EPO topical ocular administration has not been tested yet and its bioavailability could be improved by mucoadhesive hydrogels. Thus, this study aimed to develop and evaluate a chitosan (CS) and hyaluronic acid (HA) nanoparticulate system for topical ocular delivery of EPO. Nanoparticles were prepared by ionotropic gelation using six different HAs (HA1-HA6), and characterized by size, zeta potential (ZP), polydispersity index (Pdi), cytotoxicity and mucoadhesion. Encapsulation efficiency and drug loading capacity were also determined. Ex vivo permeation was tested using fresh porcine corneas, scleras and conjunctivas. The permeated EPO was quantified by ELISA, and its presence in the membranes was confirmed by immunohistochemistry. Nanoparticles (NPs) presented size ≤300 nm, ZP around +30 mV and low Pdi (0.167-0.539) at a 1:1 CS:HA mass ratio. The most suitable HA was HA6 (300 kDa - Eye), which had the best mucoadhesive properties. CS/HA6-EPO nanoformulation permeated more rapidly through porcine conjunctiva, followed by sclera and thirdly by cornea, as assessed by immunohistochemistry. All formulations were noncytotoxic on ARPE-19 and HaCaT cell lines, as evaluated by metabolic and membrane integrity tests. In conclusion, CS/HA6-EPO NPs could be a promising formulation for increasing EPO ocular bioavailability by enhancing its retention time and permeation through the different ocular membranes.

Ex vivo permeation of erythropoietin through porcine conjunctiva, cornea, and sclera.

The aim of this study is to test the permeation of human recombinant erythropoietin (rHuEPO) across conjunctiva, cornea, and sclera in an ex vivo model. Thirty fresh pig eyes were collected from a slaughterhouse. Conjunctivas (n = 10), corneas (n = 10), and scleras (n = 10) were surgically dissected from surrounding tissues. Ocular membranes were placed into Franz diffusion cells and rHuEPO was administered into the donor phase of each cell, except for control samples. Samples were collected from the receptor phase at seven time points, from 30 min to 6 h of incubation. Erythropoietin (EPO) was quantified by enzyme-linked immunosorbent assay (ELISA) technique. Ocular membranes immunohistochemistry was also performed at the end of the study. EPO was detected in all test samples. After 6 h of incubation, conjunctiva was the most permeable membrane to rHuEPO (509.3 ± 89.8 mIU/cm2, corresponding to 0.52% of the total rHuEPO administered on the donor phase), followed by sclera (359.1 ± 123.7 mIU/cm2, corresponding to 0.35%) and finally cornea (71.0 ± 31.8 mIU/cm2, corresponding to 0.07%). Differences between ocular membranes' permeation were statistically significant (p < 0.001). EPO immunostaining signal was positive for the three ocular membranes. We have demonstrated in an ex vivo model that porcine conjunctiva, cornea, and sclera are permeable to rHuEPO protein. These are promising results concerning ocular EPO administration.

Efficacy of medical grade honey in the management of canine otitis externa - a pilot study.

BACKGROUND: The high prevalence of antimicrobial resistance within otic pathogens has created a need for alternative therapies of otitis externa (OE). Evidence suggests that medical grade honey (MGH) may be effective against drug-resistant pathogens. HYPOTHESIS/OBJECTIVES: The efficacy of a commercial MGH compound was assessed in an open clinical trial. We hypothesized that it would be an effective alternative to conventional treatments. ANIMALS: Client-owned dogs (n = 15) with a confirmed diagnosis of infectious OE were enrolled in this pilot study. METHODS: Dogs were prescribed MGH (1 mL daily per ear) until cure was achieved or for a maximum of 21 d. Evaluation was based on weekly clinical scores, cytological progression and owner assessments of pruritus. Swab samples were submitted for culture and susceptibility testing. MGH was tested for biocidal activity against the bacterial isolates. RESULTS: Medical grade honey promoted rapid clinical progress, with 70% of dogs achieving clinical cure between days 7 and 14 and over 90% having resolved by Day 21. There was a decrease in clinical scores throughout the duration of the trial (P < 0.001) and owner-assessed pruritus also decreased significantly (P < 0.05). In vitro assays of the biocidal activity of MGH showed activity against all bacterial isolates, including meticillin-resistant strains of Staphylococcus pseudintermedius (MRSP) and other species of drug-resistant bacteria. CONCLUSION AND CLINICAL IMPORTANCE: Medical grade honey was successful in both clinical and laboratory settings, thus demonstrating its potential of becoming an alternative treatment for canine OE.

Molecular detection of haemotropic Mycoplasma species in urban and rural cats from Portugal.

OBJECTIVES: The aim of the present study was to evaluate the prevalence of haemoplasma infection in cats in Portugal and to assess risk factors for infection. METHODS: Real-time polymerase chain reaction techniques were used to assess 236 urban and rural cats from central and southern Portugal. RESULTS: The overall prevalence of haemoplasma in the target population was 27.1% (64/236), with individual species' prevalences as follows: 17.8% (42/236) 'Candidatus Mycoplasma haemominutum' (CMhm), 14.4% (34/236) Mycoplasma haemofelis (Mhf) and only 5.9% (14/236) 'Candidatus Mycoplasma turicensis' (CMt). Multiple infections were detected in 8.1% (19/236) of the samples, with triple and double infections with Mhf and CMhm being most commonly detected (5.9% [14/236] of cats). Haemoplasma infection was significantly higher in shelter cats (P = 0.015) than in cats with other lifestyles (eg, free-roaming/house pet/blood donors). Haemoplasma prevalence was also higher in cats with feline immunodeficiency virus infection (FIV; P = 0.011). Although sex was not significantly associated with haemoplasma infection (P = 0.050), CMt was predominantly found in males (P = 0.032). Also, the presence of haemoplasma multiple infections was statistically associated with being in a shelter (P = 0.021), male (P = 0.057) and with FIV co-infection (P = 0.004). No evidence of an association between haemoplasma infection and geographical location, age or feline leukaemia virus co-infection was found. CONCLUSIONS AND RELEVANCE: The results obtained in our study are consistent with the documented worldwide prevalence of feline haemoplasma infections, suggesting that the three main feline haemoplasma species are common in Portugal.