The aquaculture industry is constantly increasing its fish production to provide enough products to maintain fish consumption worldwide. However, the increased production generates susceptibility to infectious diseases that cause losses of millions of dollars to the industry. Conventional treatments are based on antibiotics and antivirals to reduce the incidence of pathogens, but they have disadvantages, such as antibiotic resistance generation, antibiotic residues in fish, and environmental damage. Instead, functional foods with active compounds, especially antimicrobial peptides that allow the generation of prophylaxis against infections, provide an interesting alternative, but protection against gastric degradation is challenging. In this study, we evaluated a new immunomodulatory recombinant peptide, CATH–FLA, which is encapsulated in chitosan microparticles to avoid gastric degradation. The microparticles were prepared using a spray drying method. The peptide release from the microparticles was evaluated at gastric and intestinal pH, both in vitro and in vivo. Finally, the biological activity of the formulation was evaluated by measuring the expression of il-1β, il-8, ifn-γ, Ifn-α, and mx1 in the head kidney and intestinal tissues of rainbow trout (Oncorhynchus mykiss). The results showed that the chitosan microparticles protect the CATH–FLA recombinant peptide from gastric degradation, allowing its release in the intestinal portion of rainbow trout. The microparticle-protected CATH–FLA recombinant peptide increased the expression of il-1β, il-8, ifn-γ, ifn-α, and mx1 in the head kidney and intestine and improved the antiprotease activity in rainbow trout. These results suggest that the chitosan microparticle/CATH–FLA recombinant peptide could be a potential prophylactic alternative to conventional antibiotics for the treatment of infectious diseases in aquaculture.

Background: Interferons (IFNs) are cytokines involved in the immune response with a synergistic regulatory effect on the immune response. They are therapeutics for various viral and proliferative conditions, with proven safety and efficacy. Their clinical application is challenging due to the molecules’ size, degradation, and pharmacokinetics. We are working on new drug delivery systems that provide adequate therapeutic concentrations for these cytokines and prolong their half-life in the circulation, such as nanoformulations. Methods: Through nanoencapsulation using electrospray technology and biocompatible and biodegradable polymers, we are developing a controlled release system based on nanoparticles for viral infections of the respiratory tract. Results: We developed a controlled release system for viral respiratory tract infections. A prototype nanoparticle with a core was created, which hydrolyzed the polyvinylpyrrolidone (PVP) shell , releasing the active ingredients interferon-alpha (IFN-α) and interferon-gamma (IFN-γ). The chitosan (QS) core degraded slowly, with a controlled release of IFN-α. The primary and rapid effect of the interferon combination ensured an antiviral and immunoregulatory response from day one, induced by IFN-α and enhanced by IFN-γ. The multilayer design demonstrated an optimal toxicity profile. Conclusions: This formulation is an inhaled dry powder intended for the non-invasive intranasal route. The product does not require a cold chain and has the potential for self-administration in the face of emerging viral infections. This novel drug has applications in multiple infectious, oncological, and autoimmune conditions, and further development is proposed for its therapeutic potential. This prototype would ensure greater bioavailability, controlled release, fewer adverse effects, and robust biological action through the simultaneous action of both molecules.

Interferons (IFNs) are cytokines involved in the immune response with synergistic regulatory action. They are therapeutics for various viral and proliferative conditions, with proven safety and efficacy. Their clinical application presents difficulties due to the molecules' size, degradation, and pharmacokinetics. We developed a controlled release system for viral respiratory tract infections. A core-shell nanoparticle was prototyped, which hydrolyzed the shell (polyvinylpyrrolidone), releasing the active ingredients IFN-α and IFN-γ. The core (chitosan) degraded slowly, with a controlled release of IFN-α. The primary and rapid effect of the combination of interferons ensured an antiviral and immunoregulatory response from day one, induced by IFN-α and enhanced by IFN-γ. The multilayer design demonstrated an optimal toxicity profile. This formulation is an inhaled dry powder targeted for the non-invasive intranasal route. This prototype would ensure greater bioavailability, controlled release, fewer adverse effects, and robust biological action thanks to the simultaneous impact of both molecules.

Early embryonic loss is a significant cause of reproductive inefficiency and economic loss in cattle, largely due to inadequate maternal recognition of pregnancy and premature luteolysis. Interferon tau (IFN-τ), a trophoblast-derived signaling molecule, is essential for maintaining corpus luteum function and embryo survival in ruminants, but its rapid degradation and short half-life have limited its practical use. This study developed a novel delivery system for bovine recombinant IFN-τ (brIFN-τ) produced in Pichia pastoris, utilizing chitosan-based microencapsulation and starch-chitosan hydrogels for sustained intrauterine release. The recombinant protein was successfully expressed, purified, and structurally validated, confirming its interaction with bovine interferon receptors. Encapsulated IFN-τ showed controlled, prolonged in vitro release and retained biological activity, demonstrated by increased viability and antiviral response in bovine cells exposed to Mengo virus. In vivo, the microencapsulated formulation was safe and effectively inhibited luteolysis, as shown by sustained progesterone levels and reduced corpus luteum regression compared to controls. These results indicate that hydrogel-delivered, microencapsulated brIFN-τ is a promising biotechnological strategy to modulate luteolysis, enhance maternal recognition of pregnancy, and reduce early embryonic loss in cattle, potentially improving reproductive efficiency and supporting more sustainable livestock management.

Early embryonic loss is a major cause of reproductive inefficiency in cattle, primarily due to premature luteolysis. Interferon tau (IFN-τ), secreted by the trophoblast, plays a critical role in maternal recognition of pregnancy by maintaining corpus luteum function. However, its practical application has been limited by its rapid degradation and short half-life in vivo. Here, we developed a novel formulation of recombinant bovine IFN-τ, combining chitosan-based microencapsulation with starch–chitosan hydrogel delivery, enabling sustained intrauterine release. This dual-delivery strategy offers a significant improvement over conventional IFN-τ administration methods that rely on repeated intrauterine infusions of soluble protein. The rbIFN-τ was expressed in Pichia pastoris, purified to 90.1% homogeneity, and structurally validated via homology modeling and molecular docking, confirming its interaction with type I interferon receptors. The encapsulated formulation retained antiviral activity, stimulated transcription of interferon-stimulated genes (PKR, OAS1, OAS2), and showed sustained release in vitro for up to 26 days. In vivo evaluation demonstrated safety and biological efficacy, with treated cattle showing inhibited luteolysis, sustained serum progesterone levels, and preserved corpus luteum integrity. This formulation represents a promising biotechnological approach to improve reproductive efficiency through a long-acting, species-specific IFN-τ delivery system.

There is a critical gap in the preclinical research of recombinant human interferons (rhIFNα-2b and rhIFN-γ), as most studies focus on modified variants, which complicates the understanding of the native molecules’ properties. This study addresses this limitation by comprehensively evaluating the structural stability and intrinsic toxicity of purified IFNs. Our findings confirm that both interferons retain their bioactivity (antiviral, antiproliferative, and immunomodulatory) and exhibit remarkable stability under controlled conditions. Accelerated stability assays showed that neither protein lost biological potency after 18 days at various temperatures, supporting their potential as liquid formulations. Acute and sub-chronic toxicity studies in rodent, non-rodent, and higher-organism animal models showed no signs of toxicity, even at doses 100 to 300 times higher than therapeutic levels. These assays, combined with the absence of pyrogens, support a favorable safety profile for clinical use, with no evidence of systemic or structural damage. This work establishes a reproducible experimental model and lays the groundwork for future preclinical evaluations. We underscore the importance of characterizing the safety profile of active pharmaceutical ingredients from the earliest stages of biopharmaceutical development to ensure a safe and well-founded transition to human clinical trials. Furthermore, these results open the door for the development of advanced formulations and alternative routes of administration, such as the intranasal route, an area with significant potential.