Alterations in tissue oxygen pressure contribute to a number of diseases, including rheumatoid arthritis (RA). Low partial pressure of oxygen, a condition known as hypoxia, is a relevant feature in RA since it is involved in angiogenesis, inflammation, apoptosis, cartilage degradation, energy metabolism, and oxidative damage. Therefore, alterations in hypoxia-related signaling pathways are considered potential mechanisms of disease pathogenesis. The objective of this review is to highlight and update our current knowledge of the role of hypoxia in the pathogenesis of RA. We describe the experimental evidence that RA synovial tissue exists in a hypoxic state, as well as the origin and involvement of synovial hypoxia in different aspects of the pathogenic process.

Wound healing is a complex process, and propolis, a natural resin with antimicrobial, anti-inflammatory, and antioxidant properties, emerges as a promising candidate for its treatment. This systematic review analyzed 26 studies on propolis-functionalized biomaterials. Great diversity was observed in materials and incorporation techniques, including direct blending, surface coating, and nanoencapsulation. Mostly based on polysaccharides like chitosan, pectin, and bacterial cellulose, these formulations showed biocompatibility, biodegradability, and promoted inflammation reduction and tissue repair. In vitro assays confirmed high biocompatibility (>80% cell viability) and antimicrobial activity, while in vivo studies validated regenerative benefits. Despite their potential, marked heterogeneity in propolis composition (intrinsically variable due to its botanical and geographical origin, and processing methods), coupled with diverse concentrations used and the lack of standardization in assessment methods and results reporting, significantly limits cross-study comparability and reproducibility. Overcoming these challenges requires promoting greater standardization in extraction, characterization, and evaluation protocols, including chemical fingerprinting and more detailed and consistent reporting of findings. Despite these limitations, propolis–polysaccharide systems hold strong clinical potential, with further standardization and well-designed preclinical studies being essential for their effective translation, especially in chronic wound management.

Physical exercise (PE) is recommended for Rheumatoid Arthritis (RA), but the molecular and biological mechanisms that impact the inflammatory process and joint destruction in RA remain unknown. The objective of this study was to evaluate the effect of PE on the histological and transcriptional changes in the joints of adjuvant-induced arthritis (AIA) rat model. AIA rats were subjected to PE on a treadmill for eight weeks. The joints were subjected to histological and microarray analysis. The differentially expressed genes (DEGs) by PE in the arthritic rats were obtained from the microarray. The bioinformatic analysis allowed the association of these genes in biological processes and signaling pathways. PE induced the differential expression of 719 genes. The DEGs were significantly associated with pathogenic mechanisms in RA, including HIF-1, VEGF, PI3-Akt, and Jak-STAT signaling pathways, as well as response to oxidative stress and inflammatory response. At a histological level, PE exacerbated joint inflammatory infiltrate and tissue destruction. The PE exacerbated the stressed joint environment aggravating the inflammatory process, the hypoxia, and the oxidative stress, conditions described as detrimental in the RA joints. Research on the effect of PE on the pathogenesis process of RA is still necessary for animal models and human.

Cancer is a complex disease due to its high variability and resistance to conventional treatments. The search for new therapies has prompted the study of less invasive natural sources, such as endophytic bacteria from medicinal plants. Bacillus subtilis is known to produce bioactive metabolites with promising pharmacological properties. This study evaluated the antitumor activity of the endophyte B. subtilis from Ibervillea sonorae against murine L5178Y-R lymphoma cells within in vitro and in vivo models. B. subtilis methanol extract was fractionated in hexane, chloroform, and methanol, with the chloroform partition showing the highest tumor cell growth inhibition (IC₅₀ = 34.62 ± 0.180 µg/mL) and the highest selectivity index (SI = 15.53) when compared with the hexane and methanol partitions. The in vivo study showed that mice treated with 10 mg/kg of the chloroform partition significantly (p < 0.01) reduced the tumor volume and weight without affecting tumor-free body weight. The maximum tolerated dose test indicated that 10 mg/kg was safe and well tolerated. These results indicate that B. subtilis may be a promising source of selective antitumor compounds.

Postsurgical infections are an important cause of implant failure, and biomaterials such as Chitosan can be used as an antimicrobial coating to address this important problem. Characterization of silver distribution was performed by several methods, including Electron scanning microscopy (SEM), Inductively coupled plasma (ICP), and Infrared spectrometry (IR). Antimicrobial activity was tested against Candida albicans ATCC 10231, Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa BAA-1744 ATCC 109246. The inhibition assays showed that Chitosan films inhibited 68% of C. albicans growth and 23.5% of E. coli growth; the rest of the microorganisms did not have any statistically relevant inhibition. E. coli, P. aeruginosa, and C. albicans were completely inhibited in films with 0.25 mg/mL of AgNO₃ and inhibited 82.5% of S. aureus. The mechanism of integration and release of silver in the films was analyzed by the Density Functional Theory (DFT), considering this analysis of geometry optimization as well as infrared spectroscopy. DFT analysis showed that AgNO₃ is not trapped by covalence in chitosan, being a more stable system when it is closer to an OH group. Chitosan films functionalized with antimicrobial compounds are a promising antimicrobial coating for use in biomaterials to prevent postsurgical complications.