FcRn as a Transporter for Nasal Delivery of Biologics: A Systematic Review

Expansion of platform physiologically-based pharmacokinetic model for monoclonal antibodies towards different preclinical species: cats, sheep, and dogs

Monoclonal antibodies (mAbs) are becoming an important therapeutic option in veterinary medicine, and understanding the pharmacokinetic (PK) of mAbs in higher-order animal species is also important for human drug development. To better understand the PK of mAbs in these animals, here we have expanded a platform physiological-based pharmacokinetic (PBPK) model to characterize the disposition of mAbs in three different preclinical species: cats, sheep, and dogs. We obtained PK data for mAbs and physiological parameters for the three different species from the literature. We were able to describe the PK of mAbs following intravenous (IV) or subcutaneous administration in cats, IV administration in sheep, and IV administration dogs reasonably well by fixing the physiological parameters and just estimating the parameters related to the binding of mAbs to the neonatal Fc receptor. The platform PBPK model presented here provides a quantitative tool to predict the plasma PK of mAbs in dogs, cats, and sheep. The model can also predict mAb PK in different tissues where the site of action might be located. As such, the mAb PBPK model presented here can facilitate the discovery, development, and preclinical-to-clinical translation of mAbs for veterinary and human medicine. The model can also be modified in the future to account for more detailed compartments for certain organs, different pathophysiology in the animals, and target-mediated drug disposition.

Critical appraisal tools used in systematic reviews of in vitro cell culture studies: A methodological study

Systematic reviews (SRs) of preclinical studies are marked with poor methodological quality. In vitro studies lack assessment tools to improve the quality of preclinical research. This methodological study aimed to identify, collect, and analyze SRs based on cell culture studies to highlight the current appraisal tools utilized to support the development of a validated critical appraisal tool for cell culture in vitro research. SRs, scoping reviews, and meta-analyses that included cell culture studies and used any type of critical appraisal tool were included. Electronic search, study selection, data collection and methodological quality (MQ) assessment tool were realized. Further, statistical analyses regarding possible associations and correlations between MQ and collected data were performed. After the screening process, 82 studies remained for subsequent analysis. A total of 32 different appraisal tools were identified. Approximately 60% of studies adopted pre-structured tools not designed for cell culture studies. The most frequent instruments were SYRCLE (n = 14), OHAT (n = 9), Cochrane Collaboration's tool (n = 7), GRADE (n = 6), CONSORT (n = 5), and ToxRTool (n = 5). The studies were divided into subgroups to perform statistical analyses. A significant association (OR = 5.00, 95% CI = 1.54-16.20, p = 0.008) was found between low MQ and chronic degenerative disorders as topic of SR. Several challenges in collecting information from the included studies led to some modifications related to the previously registered protocol. These results may serve as a basis for further development of a critical appraisal tool for cell culture studies capable of capturing all the essential factors related to preclinical research, therefore enhancing the practice of evidence-based.

In vivo intranasal delivery of coagulation factor IX: a proof-of-concept study

BACKGROUND

Hemophilia B (HB) is a bleeding disorder characterized by coagulation factor (F) IX (FIX) deficiency. The current standard-of-care for severe HB is prophylaxis with long-term repetitive intravenous (i.v.) infusions of recombinant FIX (rFIX) with standard half-life or extended half-life. Unmet needs remain regarding the development of non-invasive administration routes for coagulation factors. The aim of this study was to evaluate the effectiveness of intranasal delivery (IND) of rFIX and rFIX fused to Fc fragment (rFIX-Fc) in mice.

METHODS

Drops of rFIX and rFIX-Fc were deposited in the nostrils of wild-type, FcRn knock-out, FcRn humanized, and FIX knock-out mice. rFIX mucosal uptake was evaluated by measuring plasma FIX antigen and FIX activity (FIX:C) levels, and by performing histologic analysis of the nasal mucosa following IND.

RESULTS

After IND, both rFIX and rFIX-Fc were equally delivered to the blood compartment, irrespective of the mouse strain studied, mostly through a passive mechanism of transportation across the mucosal barrier, independent of FcRn receptor. Both plasma FIX antigen and FIX:C activity levels increased following IND in FIX knock-out mice.

CONCLUSION

This proof-of-concept study describes evidence supporting the nasal route as an alternative to FIX i.v. infusion for the treatment of HB.

My Name Is Legion, for We Are Many-The Complex Community of Antibody Receptors

Antibodies act as the central mediators of immunological defense mechanisms, therapeutic agents within clinics, and the mediators of various immune-mediated disorders [...].

Nogo-A antibody delivery through the olfactory mucosa mitigates experimental autoimmune encephalomyelitis in the mouse CNS

Systemic administration of Nogo-A-neutralizing antibody ameliorates experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. However, the blood-brain barrier (BBB) is a major obstacle limiting the passage of systemically applied antibody to the CNS. To bypass the BBB, in the present study we tested the intranasal route of administration by targeting the olfactory mucosa with the Nogo-A-blocking antibody 11C7 mAb in myelin oligodendrocyte glycoprotein-induced EAE. Antibodies were specifically administered onto the olfactory mucosa using a microcatheter. Antibody distribution was examined in the CNS by ELISA and light-sheet microscopy. The effects of 11C7 mAb on Nogo-A signaling were assessed by Western blotting. EAE-induced deficits were monitored daily. Demyelination was observed on spinal cord histological sections. Gene expression changes were followed by trancriptomic analyses. A sensitive capture ELISA revealed a rapid and widespread distribution of 11C7 mAb in the CNS, including the olfactory bulb, the cerebellum and the lumbar spinal cord, but not in the CSF. Light-sheet microscopy allowed to observe antibody accumulation in the parenchyma, thus demonstrating nose-to-brain transfer of IgG. At the functional level, the widespread penetration of 11C7 mAb in the CNS, including the thoracolumbar spinal cord, resulted in the improvement of motor symptoms and in the preservation of myelin in the spinal cord of EAE mice. This was accompanied by Nogo-A signaling downregulation, as reflected by the decreased level of phosphorylated cofilin observed by Western blotting in the cerebellum. In the brain of EAE score-matched animals, 11C7 modified the expression of genes that can influence neurotransmission and cognitive functions, independently of the demyelination phenotype in the spinal cord. In conclusion, our data show the feasibility of olfactory mucosa-directed administration for the delivery of therapeutic antibodies targeting CNS antigens in EAE mice.

Optimization and Characterization of Novel ALCAM-Targeting Antibody Fragments for Transepithelial Delivery

Activated leukocyte cell adhesion molecule (ALCAM) is a cell adhesion molecule that supports T cell activation, leukocyte migration, and (lymph)angiogenesis and has been shown to contribute to the pathology of various immune-mediated disorders, including asthma and corneal graft rejection. In contrast to monoclonal antibodies (mAbs) targeting ALCAM's T cell expressed binding partner CD6, no ALCAM-targeting mAbs have thus far entered clinical development. This is likely linked with the broad expression of ALCAM on many different cell types, which increases the risk of eliciting unwanted treatment-induced side effects upon systemic mAb application. Targeting ALCAM in surface-exposed tissues, such as the lungs or the cornea, by a topical application could circumvent this issue. Here, we report the development of various stability- and affinity-improved anti-ALCAM mAb fragments with cross-species reactivity towards mouse, rat, monkey, and human ALCAM. Fragments generated in either mono- or bivalent formats potently blocked ALCAM-CD6 interactions in a competition ELISA, but only bivalent fragments efficiently inhibited ALCAM-ALCAM interactions in a leukocyte transmigration assay. The different fragments displayed a clear size-dependence in their ability to penetrate the human corneal epithelium. Furthermore, intranasal delivery of anti-ALCAM fragments reduced leukocyte infiltration in a mouse model of asthma, confirming ALCAM as a target for topical application in the lungs.

Targeted modulation of immune cells and tissues using engineered biomaterials

Therapies modulating the immune system offer the prospect of treating a wide range of conditions including infectious diseases, cancer and autoimmunity. Biomaterials can promote specific targeting of immune cell subsets in peripheral or lymphoid tissues and modulate the dosage, timing and location of stimulation, thereby improving safety and efficacy of vaccines and immunotherapies. Here we review recent advances in biomaterials-based strategies, focusing on targeting of lymphoid tissues, circulating leukocytes, tissue-resident immune cells and immune cells at disease sites. These approaches can improve the potency and efficacy of immunotherapies by promoting immunity or tolerance against different diseases.

Serum Albumin in Health and Disease: Esterase, Antioxidant, Transporting and Signaling Properties

Being one of the main proteins in the human body and many animal species, albumin plays a decisive role in the transport of various ions-electrically neutral and charged molecules-and in maintaining the colloidal osmotic pressure of the blood. Albumin is able to bind to almost all known drugs, as well as many nutraceuticals and toxic substances, largely determining their pharmaco- and toxicokinetics. Albumin of humans and respective representatives in cattle and rodents have their own structural features that determine species differences in functional properties. However, albumin is not only passive, but also an active participant of pharmacokinetic and toxicokinetic processes, possessing a number of enzymatic activities. Numerous experiments have shown esterase or pseudoesterase activity of albumin towards a number of endogeneous and exogeneous esters. Due to the free thiol group of Cys34, albumin can serve as a trap for reactive oxygen and nitrogen species, thus participating in redox processes. Glycated albumin makes a significant contribution to the pathogenesis of diabetes and other diseases. The interaction of albumin with blood cells, blood vessels and tissue cells outside the vascular bed is of great importance. Interactions with endothelial glycocalyx and vascular endothelial cells largely determine the integrative role of albumin. This review considers the esterase, antioxidant, transporting and signaling properties of albumin, as well as its structural and functional modifications and their significance in the pathogenesis of certain diseases.