Effects of iota-carrageenan on ocular Chlamydia trachomatis infection in vitro and in vivo

κ-Carrageenan from Grateloupia filicina protects against PM2.5-induced intraocular pressure elevation

This study investigates the efficacy of GFP01, an almost pure κ-carrageenan derived from Grateloupia filicina, in counteracting intraocular pressure (IOP) elevation induced by PM2.5 exposure. GFP01, characterized by a molecular weight of 97.8 kDa, exhibits a linear backbone composed of 4-O-sulfated-β-D-galactose and 3,6-anhydro-α-D-galactose. In a murine model subjected to PM2.5-induced high IOP, GFP01 treatment significantly mitigated IOP compared to the PM2.5 group (n = 12, p < 0.01). In vitro assays revealed a 27.7 % increase in cell viability in human trabecular meshwork cells (HTMCs) treated with GFP01 compared to controls exposed to PM2.5 (p < 0.001, n = 5 cell lines). Additionally, GFP01 decreased PM2.5-induced transendothelial electrical resistance (TEER) of angular aqueous plexus (AAP) cells by 35.8 % at 48 h post-treatment (p < 0.05, n = 3 cell lines). Western blot analysis further demonstrated GFP01's role in inhibiting NLRP3/caspase-1/GSDMD/IL-1β axis in ocular tissues and HTMCs. Cytotoxicity assessment and slit-lamp imaging confirmed the safety of GFP01. In conclusion, GFP01 demonstrates a significant protective effect against PM2.5-induced IOP elevation, making it a promising therapeutic candidate for clinical applications.

Sulfated Glycosaminoglycans as Inhibitors for Chlamydia Infections: Molecular Weight and Sulfation Dependence

Glycosaminoglycans (GAGs) play a pivotal role in pathogen attachment and entry into host cells, where the interaction with GAGs is critical for a diverse range of bacteria and viruses. This study focuses on elucidating the specific interactions between sulfated GAGs and the adhesin OmcB (Outer membrane complex protein B) of Chlamydia species, examining how structural characteristics of GAGs, such as sulfation degree and molecular weight, influence their binding affinity and thereby affect bacterial infectivity. A surface-based binding assay is established to determine the binding constants of OmcB with various GAGs. It is shown that increased sulfation and higher molecular weight enhance GAG binding to OmcB. These findings are further validated using cell assays, which shows that the addition of sulfated GAGs reduces OmcB-cell binding and inhibits the attachment of C. pneumoniae elementary bodies (EBs), underscoring the pivotal role of specific GAGs in chlamydial infections. Notably, heparin exhibites a stronger inhibitory effect on OmcB compare to GAGs with similar sulfation degrees and molecular weights, suggesting that particular molecular architectures may optimize binding interactions.

Biomedical applications of functional hydrogels: Innovative developments, relevant clinical trials and advanced products

Functional hydrogels are used for numerous biomedical applications such as tissue engineering, wound dressings, lubricants, contact lenses and advanced drug delivery systems. Most of them are based on synthetic or natural polymers forming a three-dimensional network that contains aqueous media. Among synthetic polymers, poly(meth)acrylates, polyethyleneglycols, poly(vinylalcohols), poly(vinylpyrrolidones), PLGA and poly(urethanes) are of high relevance, whereas natural polymers are mainly polysaccharides such as hyaluronic acid, alginate or chitosan and proteins such as albumin, collagen or elastin. In contrast to most synthetic polymers, natural polymers are biodegradable. Both synthetic and natural polymers are often chemically modified in order to improve or induce favorable properties and functions like high mechanical strength, stiffness, elasticity, high porosity, adhesive properties, in situ gelling properties, high water binding capacity or drug release controlling properties. Within this review we provide an overview about the broad spectrum of biomedical applications of functional hydrogels, summarize innovative approaches, discuss the concept of relevant functional hydrogels that are in clinical trials and highlight advanced products as examples for successful developments.

Interaction of Liposomes Containing the Carrageenan/Echinochrome Complex with Human HaCaT Keratinocytes In Vitro

Liposomal drug delivery systems are successfully used in various fields of medicine for external and systemic applications. Marine organisms contain biologically active substances that have a unique structure and exhibit a wide range of biological activities. Polysaccharide of red seaweed (carrageenan (CRG)), and water-insoluble sea urchin pigment (echinochrome (Ech)) interact with each other and form a stable complex. We included the CRG/Ech complex in liposomes for better permeability into cells. In our research, tetramethylrhodamine isothiocyanate TRITC-labeled CRG was synthesized to study the interaction of the complex encapsulated in liposomes with human epidermal keratinocytes (HaCaTs) widely used to expose the skin to a variety of substances. Using confocal microscopy, we found that liposomes were able to penetrate HaCaT cells with maximum efficiency within 24 h, and pre-incubation of keratinocytes with liposomes resulted in the delivery of the CRG/Ech complex into the cytoplasm. We investigated the anti-inflammatory effects of liposomes, including the lysosomal regulation, increased intracellular ROS levels, and increased NO synthesis in lipopolysaccharide (LPS)- or Escherichia coli (E. coli)-induced inflamed skin cells. Liposomes containing the CRG/Ech complex significantly reduced lysosomal activity by 26% in LPS-treated keratinocytes and decreased ROS levels in cells by 23% after LPS exposure. It was found that liposomes with the complex improved the migration of HaCaT keratinocytes incubated with high-dose LPS by 47%. The results of the work, taking into account the good permeability of liposomes into keratinocytes, as well as the anti-inflammatory effect on cells treated with LPS or E. coli, show the prospects of using liposomes containing the CRG/Ech complex as an anti-inflammatory agent in the fight against skin infections.

Carrageenan films as promising mucoadhesive ocular drug delivery systems

Polymer mucoadhesive films being developed for use in ophthalmology represent a new tool for drug delivery and are considered an alternative to traditional dosage forms. Due to their mucoadhesive properties, carrageenans (CRGs) are widely used in various forms for drug delivery. In this study, films based on CRGs of various structural types (κ/β, κ, x, and λ) for use in ophthalmology were studied. The films were loaded with the active substance echinochrome (ECH), a sea urchin pigment used in ophthalmology. Spectral data showed that ECH remained stable after its incorporation into the CRG films and did not oxidize for at least six months. Hydrophilic CRG films with a thickness of 10-12 µm were characterized in terms of their swelling and mucoadhesive properties. The rheological properties of solutions formed after film dissolution in artificial tears were also assessed. κ- and κ/β-CRG films with ECH exhibited pseudoplastic behavior after rehydrating films with an artificial tear solution. The CRG-loaded films had different swelling characteristics depending on the structure of the CRG used. The films based on highly sulfated CRGs dissolved in artificial tears, while the films of low-sulfated κ/β-CRG exhibited limited swelling. All studied ECH-loaded films exhibited mucoadhesive properties, which were evaluated by a texture analyzer using mucous tissue of the small intestine of the pig as a model. There was a slight prolongation of ECH release from CRG films in artificial tears. The effect of CRG/ECH on the epithelial cell lines of the outer shell of the human eye was investigated. At low concentrations, ECH in the composition of the CRG/ECH complex had no cytotoxic effect on corneal epithelial and conjunctival human cells. The use of ECH-containing films can prevent the drug from being immediately washed away by tears and help to retain it by increasing viscosity and having mucoadhesive properties.

Exploring carrageenan: From seaweed to biomedicine-A comprehensive review

Biomaterials are pivotal in the realms of tissue engineering, regenerative medicine, and drug delivery and serve as fundamental building blocks. Within this dynamic landscape, polymeric biomaterials emerge as the frontrunners, offering unparalleled versatility across physical, chemical, and biological domains. Natural polymers, in particular, captivate attention for their inherent bioactivity. Among these, carrageenan (CRG), extracted from red seaweeds, stands out as a naturally occurring polysaccharide with immense potential in various biomedical applications. CRG boasts a unique array of properties, encompassing antiviral, antibacterial, immunomodulatory, antihyperlipidemic, antioxidant, and antitumor attributes, positioning it as an attractive choice for cutting-edge research in drug delivery, wound healing, and tissue regeneration. This comprehensive review encapsulates the multifaceted properties of CRG, shedding light on the chemical modifications that it undergoes. Additionally, it spotlights pioneering research that harnesses the potential of CRG to craft scaffolds and drug delivery systems, offering high efficacy in the realms of tissue repair and disease intervention. In essence, this review celebrates the remarkable versatility of CRG and its transformative role in advancing biomedical solutions.

Recent advances in cellulose, pectin, carrageenan and alginate-based oral drug delivery systems

Polymers-based drug delivery systems constitute one of the highly explored thrust areas in the field of the medicinal and pharmaceutical industries. In the past years, the properties of polymers have been modified in context to their solubility, release kinetics, targeted action site, absorption, and therapeutic efficacy. Despite the availability of diverse synthetic polymers for the bioavailability enhancement of drugs, the use of natural polymers is still highly recommended due to their easy availability, accessibility, and non-toxicity. The aim of the review is to provide the available literature of the last five years on oral drug delivery systems based on four natural polymers i.e., cellulose, pectin, carrageenan, and alginate in a concise and tabulated manner. In this review, most of the information is in tabulated form to provide easy accessibility to the reader. The data related to active pharmaceutical ingredients and supported components in different formulations of the mentioned polymers have been made available.

Biological activity of algal derived carrageenan: A comprehensive review in light of human health and disease

Carrageenans are a family of natural linear sulfated polysaccharides derived from red seaweeds and used as a common food additive. Carrageenan's properties, impact on health, and aesthetic benefits have all been studied for a long time; however, the mechanisms are still unclear. In pharmaceutical aspects, carrageenan displayed potential antioxidant and immunomodulatory properties in both in vivo and in vitro action. It also contributes to potential disease-preventive activities through dynamic modulation of important intracellular signaling pathways, regulation of ROS buildup, and preservation of major cell survival and death processes which leads to potential drug development. Furthermore, the chemical synthesis of the current bioactive medicine with confirmational rearrangement may increase availability and bioactivity needs diligent examination. In this review, we give an up-to-date overview of recent research on Carrageenan with reference to health and therapeutic advantages. In addition, we have focused on structural conformation and its primary strategic deployment in disease prevention, as well as the mechanistic investigation of how it functions to combat various disease-preventive employed for future therapeutic interventions. This review may get new insights into the possible novel role of carrageenan and open up a novel disease-preventive mechanism and enhance human health.

Marine Bioactive Compounds Derived from Macroalgae as New Potential Players in Drug Delivery Systems: A Review

The marine algal ecosystem is characterized by a rich ecological biodiversity and can be considered as an unexploited resource for the discovery and isolation of novel bioactive compounds. In recent years, marine macroalgae have begun to be explored for their valuable composition in bioactive compounds and opportunity to obtain different nutraceuticals. In comparison with their terrestrial counterparts, Black Sea macroalgae are potentially good sources of bioactive compounds with specific and unique biological activities, insufficiently used. Macroalgae present in different marine environments contain several biologically active metabolites, including polysaccharides, oligosaccharides, polyunsaturated fatty acids, sterols, proteins polyphenols, carotenoids, vitamins, and minerals. As a result, they have received huge interest given their promising potentialities in supporting antitumoral, antimicrobial, anti-inflammatory, immunomodulatory, antiangiogenic, antidiabetic, and neuroprotective properties. An additional advantage of ulvans, fucoidans and carrageenans is the biocompatibility and limited or no toxicity. This therapeutic potential is a great natural treasure to be exploited for the development of novel drug delivery systems in both preventive and therapeutic approaches. This overview aims to provide an insight into current knowledge focused on specific bioactive compounds, which represent each class of macroalgae e.g., ulvans, fucoidans and carrageenans, respectively, as valuable potential players in the development of innovative drug delivery systems.

New Insights into the Structure of Kappa/Beta-Carrageenan: A Novel Potential Inhibitor of HIV-1

New insights into the structure of the hybrid κ/β-carrageenan (κ/β-CRG) of the red alga Tichocarpus crinitus have been obtained. Carrageenan oligosaccharides were prepared through the chemical and enzymatic depolymerization of κ/β-CRG with κ-carrageenase and its the enzyme-resistant fraction. The composition and distribution of the repetition units of κ/β- CRG were investigated by using the negative ion tandem MALDI-TOFMS and ESIMS method, which made it possible to prove and characterize the hybrid structure of this polysaccharide. An analysis revealed the blockwise distribution of the long β-blocks along the polysaccharide chain, with the inclusion of κ/β, μ/ν-blocks and some ι-blocks. Furthermore, the desulfated κ/β-CRG was shown to contain of –G–D– repeating units up to 3.5 kDa. Previous studies have demonstrated that CRGs suppress the replication of several viruses. Here, we established that κ/β-CRG and its oligosaccharides significantly inhibit the transduction efficiency of replication-defective lentiviral particles pseudotyped with the envelope proteins of three different viruses. We found that the polysaccharide and its oligosaccharides strongly reduced the transduction efficiency of lentiviral particles pseudotyped with GP160—the envelope protein of the human immunodeficiency virus HIV-1—when added to T-lymphocyte Jurkat cells. The CRG oligosaccharides displayed significantly higher antiviral activity.

Effects of water-filtered infrared A and visible light (wIRA/VIS) radiation on heat- and stress-responsive proteins in the retina and cornea of guinea pigs

Water-filtered infrared A and visible light (wIRA/VIS), shown to reduce chlamydial infections in vitro and in vivo, might represent an innovative therapeutic approach against trachoma, a neglected tropical disease caused by ocular infection with the bacterium C. trachomatis. In this in vivo study, we assessed the impact of wIRA radiation in combination with VIS (wavelength range 595-1400 nm, intensity 2100 W/m²) on the retina and cornea in a guinea pig animal model of inclusion conjunctivitis. We investigated the effects 19 days after wIRA/VIS irradiation by comparing a single and double wIRA/VIS treatment with a sham control. By immunolabeling and western blot analyses of critical heat- and stress-responsive proteins, we could not detect wIRA/VIS-induced changes in their expression pattern. Also, immunolabeling of specific retinal marker proteins revealed no changes in their expression pattern caused by the treatment. Our preclinical study suggests wIRA/VIS as a promising and safe therapeutic tool to treat ocular chlamydial infections.

Semi-synthesis of N-alkyl-kappa-carrageenan derivatives and evaluation of their antibacterial activity

In this article, we describe the semi-synthesis of N-alkyl-kappa-carrageenan derivatives and their antibacterial activity against Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 8739), and Pseudomonas aeruginosa (ATCC 9027). Kappa-carrageenan was submitted to partial acid hydrolysis promoting the selective cleavage of α-glycosidic bonds involving 3,6-anhydro-α-D-Galp units, giving rise to reducing low-molecular weight polysaccharide fragments, which were reacted with alkylamines of varying chain lengths by reductive amination. The carrageenan derivatives were characterized by HPSEC-MALLS-RID and 1D and 2D ¹H and ¹³C NMR spectroscopy. The antibacterial activity of N-alkyl-kappa-carrageenan derivatives was compared with N-alkyl-(1-deoxylactitol-1-yl)-amines using a microdilution test, which indicated that inhibitory activity was dependent on the degree of substitution by hydrophobic groups at the polysaccharide structure. Comparing the effect of different N-alkyl chains, those with longer chains showed higher activity.

Cross-Reactive Effects of Vaccines: Heterologous Immunity between Tetanus and Chlamydia

Vaccines can have heterologous effects on the immune system, i.e., effects other than triggering an immune response against the disease targeted by the vaccine. We investigated whether monoclonal antibodies (mAbs) specific for tetanus could cross-react with Chlamydia and confer heterologous protection against chlamydial infection. The capability of two tetanus-specific mAbs, namely mAb26 and mAb51, to prevent chlamydial infection has been assessed: (i) in vitro, by performing a neutralization assay using human conjunctival epithelial (HCjE) cells infected with Chlamydia trachomatis serovar B, and (ii) in vivo, by using a guinea pig model of Chlamydiacaviae-induced inclusion conjunctivitis. The mAb26 has been superior in comparison with mAb51 in the prevention of chlamydial infection in HCjE cells. The mAb26 has conferred ≈40% inhibition of the infection, compared to less than 5% inhibition in the presence of the mAb51. In vivo, mAb26 significantly diminished ocular pathology intensity in guinea pigs infected with C. caviae compared to either the mAb51-treated or sham-treated guinea pigs. Our data provide insights that tetanus immunization generates antibodies which induce heterologous chlamydial immunity and promote protection beyond the intended target pathogen.

Carrageenan: Drug Delivery Systems and Other Biomedical Applications

Marine resources are today a renewable source of various compounds, such as polysaccharides, that are used in the pharmaceutical, medical, cosmetic, and food fields. In recent years, considerable attention has been focused on carrageenan-based biomaterials due to their multifunctional qualities, including biodegradability, biocompatibility, and non-toxicity, in addition to bioactive attributes, such as their antiviral, antibacterial, antihyperlipidemic, anticoagulant, antioxidant, antitumor, and immunomodulating properties. They have been applied in pharmaceutical formulations as both their bioactive and physicochemical properties make them suitable biomaterials for drug delivery, and recently for the development of tissue engineering. This article provides a review of recent research on the various types of carrageenan-based biomedical and pharmaceutical applications.

The Evolution Road of Seaweed Aquaculture: Cultivation Technologies and the Industry 4.0

Seaweeds (marine macroalgae) are autotrophic organisms capable of producing many compounds of interest. For a long time, seaweeds have been seen as a great nutritional resource, primarily in Asian countries to later gain importance in Europe and South America, as well as in North America and Australia. It has been reported that edible seaweeds are rich in proteins, lipids and dietary fibers. Moreover, they have plenty of bioactive molecules that can be applied in nutraceutical, pharmaceutical and cosmetic areas. There are historical registers of harvest and cultivation of seaweeds but with the increment of the studies of seaweeds and their valuable compounds, their aquaculture has increased. The methodology of cultivation varies from onshore to offshore. Seaweeds can also be part of integrated multi-trophic aquaculture (IMTA), which has great opportunities but is also very challenging to the farmers. This multidisciplinary field applied to the seaweed aquaculture is very promising to improve the methods and techniques; this area is developed under the denominated industry 4.0.

Water-filtered Infrared A and visible light (wIRA/VIS) treatment reduces Chlamydia caviae-induced ocular inflammation and infectious load in a Guinea pig model of inclusion conjunctivitis

Trachoma is a devastating neglected tropical disease caused by Chlamydia trachomatis and the leading global cause of infectious blindness. Although antibiotic treatment against trachoma is efficient (SAFE strategy), additional affordable therapeutic strategies are of high interest. Water-filtered infrared A and visible light (wIRA/VIS) irradiation has proven to reduce chlamydial infectivity in vitro and ex vivo. The aim of this study was to evaluate whether wIRA/VIS can reduce chlamydial infection load and/or ocular pathology in vivo, in a guinea pig model of inclusion conjunctivitis. Guinea pigs were infected with 1 × 10⁶ inclusion-forming units/eye of Chlamydia caviae via the ocular conjunctiva on day 0. In infected animals, wIRA/VIS irradiation (2100 W/m²) was applied on day 2 (single treatment) and on days 2 and 4 (double treatment) post-infection (pi). wIRA/VIS reduced the clinical pathology score on days 7 and 14 pi and the conjunctival chlamydial load on days 2, 4, 7, and 14 pi in comparison with C. caviae-infected, not irradiated, controls. Furthermore, numbers of chlamydial inclusions were decreased in wIRA/VIS treated C. caviae-infected guinea pigs on day 21 pi compared to C. caviae-infected, non-irradiated, controls. Double treatment with wIRA/VIS (days 2 and 4 pi) was more efficient than a single treatment on day 2 pi. wIRA/VIS treatment did neither induce macroscopic nor histologic changes in ocular tissues. Our results indicate that wIRA/VIS shows promising efficacy to reduce chlamydial infectivity in vivo without causing irradiation related pathologies in the follow-up period. wIRA/VIS irradiation is a promising approach to reduce trachoma transmission and pathology of ocular chlamydial infection.

Integral Utilization of Red Seaweed for Bioactive Production

The hydrocolloids carrageenan and agar are the major fraction industrially extracted and commercialized from red seaweeds. However, this type of macroalgae also contains a variety of components with nutritional, functional and biological properties. In the context of sustainability and bioeconomy, where the integral utilization of the natural resources is incentivized, the sequential separation and valorization of seaweed components with biological properties of interest for food, nutraceuticals, cosmeceuticals and pharmaceuticals is proposed. In this work, a review of the available conventional and alternative greener and efficient extraction for obtaining red seaweed bioactives is presented. The potential of emerging technologies for the production of valuable oligomers from carrageenan and agar is also commented, and finally, the sequential extraction of the constituent fractions is discussed.