Novel catalase loaded nanocores for the treatment of inflammatory bowel diseases

A multifunctional composite hydrogel that sequentially modulates the process of bone healing and guides the repair of bone defects

Calcium carbonate (CaCO3), which exhibits excellent biocompatibility and bioactivity, is a well-established bone filling material for bone defects. Here, we synthesized CaCO3microspheres (CMs) to use as an intelligent carrier to load bone morphogenetic protein-2 (BMP-2). Subsequently, drug-loaded CMs and catalase (CAT) were added to methacrylated gelatin (GelMA) hydrogels to prepare a composite hydrogel for differential release of the drugs. CAT inside hydrogels was released with a fast rate to eliminate H2O2and generate oxygen. Constant BMP-2 release from CMs induced rapid osteogenesis. Resultsin vitroindicated that the composite hydrogels efficiently reduced the level of intracellular reactive oxygen species, preventing cells from being injured by oxidative stress, promoting cell survival and proliferation, and enhancing osteogenesis. Furthermore, animal experiments demonstrated that the composite hydrogels were able to inhibit the inflammatory response, regulate macrophage polarization, and facilitate the healing of bone defects. These findings indicate that a multi-pronged strategy is greatly expected to promote the bone healing by modulating pathological microenvironments.

Alginate-based drug carrier systems to target inflammatory bowel disease: A review

Inflammatory bowel disease (IBD) is an inflammatory disorder that affects the gastrointestinal tract. IBD has become an increasingly common condition in both developed and developing nations over the last few decades, owing to a variety of factors like a rising population and diets packed with processed and junk foods. While the root pathophysiology of IBD is unknown, treatments are focused on medications aimed to mitigate symptoms. Alginate (AG), a marine-derived polysaccharide, is extensively studied for its biocompatibility, pH sensitivity, and crosslinking nature. This polymer is thoroughly researched in drug delivery systems for IBD treatment, as it is naturally available, non-toxic, cost effective, and can be easily and safely cross-linked with other polymers to form an interconnected network, which helps in controlling the release of drugs over an extended period. There are various types of drug delivery systems developed from AG to deliver therapeutic agents; among them, nanotechnology-based systems and hydrogels are popular due to their ability to facilitate targeted drug delivery, reduce dosage, and increase the therapeutic efficiency. AG-based carrier systems are not only used for the sustained release of drug, but also used in the delivery of siRNA, interleukins, and stem cells for site directed drug delivery and tissue regenerating ability respectively. This review is focussed on pathogenesis and currently studied medications for IBD, AG-based drug delivery systems and their properties for the alleviation of IBD. Moreover, future challenges are also be discoursed to improve the research of AG in the field of biopharmaceuticals and drug delivery.

The Genetic Diversity and Dysfunctionality of Catalase Associated with a Worse Outcome in Crohn's Disease

Chronic gut inflammation in Crohn’s disease (CD) is associated with an increase in oxidative stress and an imbalance of antioxidant enzymes. We have previously shown that catalase (CAT) activity is permanently inhibited by CD. The purpose of the study was to determine whether there is any relationship between the single nucleotide polymorphisms (SNPs) in the CAT enzyme and the potential risk of CD associated with high levels of oxidative stress. Additionally, we used protein and regulation analyses to determine what causes long-term CAT inhibition in peripheral white mononuclear cells (PWMCs) in both active and inactive CD. We first used a retrospective cohort of 598 patients with CD and 625 age-matched healthy controls (ENEIDA registry) for the genotype analysis. A second human cohort was used to study the functional and regulatory mechanisms of CAT in CD. We isolated PWMCs from CD patients at the onset of the disease (naïve CD patients). In the genotype-association SNP analysis, the CAT SNPs rs1001179, rs475043, and rs525938 showed a significant association with CD (p < 0.001). Smoking CD patients with the CAT SNP rs475043 A/G genotype had significantly more often penetrating disease (p = 0.009). The gene expression and protein levels of CAT were permanently reduced in the active and inactive CD patients. The inhibition of CAT activity in the PWMCs of the CD patients was related to a low concentration of CAT protein caused by the downregulation of CAT-gene transcription. Our study suggests an association between CAT SNPs and the risk of CD that may explain permanent CAT inhibition in CD patients together with low CAT gene and protein expression.

Oral delivery of antioxidant enzymes for effective treatment of inflammatory disease

Oral administration of protein is very challenging for therapeutic applications due to its instability and easy degradation in the gastrointestinal tract. Herein, we reported an approach to encapsulate native anti-inflammatory proteins in wind chimes like cyclodextrin (WCC) for efficient oral protein delivery. The amphiphilic WCC can self-assemble into nanoparticles in aqueous solution and achieve superior encapsulation of two antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) by simply mixing with protein solution, avoiding any extra cumbersome steps that might inactivate protein. WCC nanovehicles can effectively protect enzyme activity and enhance their intracellular delivery. SOD and CAT co-loaded WCC nanoparticles (SC/WCC) can integrate the synergistic effect of SOD and CAT for enhancing the removal of reactive oxygen species (ROS), effectively inhibit the inflammatory response by reducing the secretion of proinflammatory factors and protect cells from ROS-induced oxidative damage. In the mouse colitis model, SC/WCC administered orally was able to efficiently accumulate in the inflamed colon, significantly inhibited the expression of proinflammatory mediators and notably alleviated the symptoms related to colitis. Therefore, we believe that the strategies we described here may provide a convenient and powerful platform for the treatment of other inflammatory diseases.

Solid Lipid Microparticles for Oral Delivery of Catalase: Focus on the Protein Structural Integrity and Gastric Protection

Protein inactivation either during the production process or along the gastrointestinal tract is the major problem associated with the development of oral delivery systems for biological drugs. This work presents an evaluation of the structural integrity and the biological activity of a model protein, catalase, after its encapsulation in glyceryl trimyristate-based solid lipid microparticles (SLMs) obtained by the spray congealing technology. Circular dichroism and fluorescence spectroscopies were used to assess the integrity of catalase released from SLMs. The results confirmed that no conformational change occurred during the production process and both the secondary and tertiary structures were retained. Catalase is highly sensitive to temperature and undergoes denaturation above 60 °C; nevertheless, spray congealing allowed the retention of most biological activity due to the loading of the drug at the solid state, markedly reducing the risk of denaturation. Catalase activity after exposure to simulated gastric conditions (considering both acidic pH and the presence of gastric digestive hydrolases) ranged from 35 to 95% depending on the carrier: increasing of both the fatty acid chain length and the degree of substitution of the glyceride enhanced residual enzyme activity. SLMs allowed the protein release in a simulated intestinal environment and were not cytotoxic against HT29 cells. In conclusion, the encapsulation of proteins into SLMs by spray congealing might be a promising strategy for the formulation of nontoxic and inexpensive oral biotherapeutic products.

Engineering Strategies for Oral Therapeutic Enzymes to Enhance Their Stability and Activity

Oral application of therapeutic enzymes is a promising and non-invasive administration that improves patient compliance. However, the gastrointestinal tract poses several challenges to the oral delivery of proteins, including harsh pH conditions and digestive proteases. A promising way to stabilise enzymes during their gastrointestinal route is by modification with polymers that can provide both steric shielding and selective interaction in different digestive compartments. We give an overview of modification technologies for oral enzymes ranging from functionalisation of native proteins, to site-specific mutation and protein-polymer engineering. We specifically focus on enzymes that are active directly in the gastrointestinal lumen and not systemically absorbed. In addition, we discuss examples of microparticle and nanoparticle encapsulated enzymes for improved oral delivery. The modification of orally administered enzymes offers a broad chemical variability and may be a promising tool for enhancing their gastrointestinal stability.