Neža Brezovec

Bacterial nanocellulose is a promising biomaterial extensively used in functional foods and for drug delivery. Moreover, its characteristics can further be potentialized whether coupled with natural bio-extracts to endow antibacterial activity. Persea americana or avocado seed extracts are rich in phytochemicals and have demonstrated their antioxidant, antimicrobial and enzymatic activities, therefore encapsulating them into bacterial nanocellulose (BNC) may offer a potential release system of antibacterial avocado seed compounds. Accordingly, this study explores the in-depth insight into the influence of different bacterial nanocellulose producing strains ( Komagataeibacter hansenii and Komagataeibacter xylinus ) and cultivation conditions (static and dynamic cultivation, fermentation time) on the bacterial nanocellulose productivity and characteristics. The obtained bacterial nanocellulose membranes and beads were characterized in terms of chemical structure, morphology and crystallinity. More profitable and productive K. xylinus was further selected for encapsulation (up to 72.89 mg) of avocado seed extracts into bacterial nanocellulose membranes and beads in order to comprehensively evaluate the kinetic release profiles and determine their antibacterial activity against Escherichia coli and Staphylococcus aureus. Results of the study show that the bacterial nanocellulose and avocado seed extracts biohybrids represent a promising immediate (up to 17.39 mg in 1 h) and sustained (up to 35.04 mg in 48 h) release systems. Kinetic release modeling and cytotoxicity assessments confirmed controlled release behavior and biocompatibility for safe antibacterial applications in cosmetics, functional foods and drug delivery.

Systemic sclerosis (SSc) is a systemic autoimmune connective tissue disease with great clinical and pathogenetic heterogeneity. Although skin is the most visible organ affected, skeletal muscles are affected in up to 96% of SSc patients and this is associated with a worse clinical outcome including increased mortality. Muscle involvement varies from patients experiencing myalgias, fibrosing myopathy to overlaps of SSc and myositis, a condition referred to as scleromyositis. In SSc muscle biopsies, muscular fibrosis, inflammation, microangiopathy and atrophy are observed, which is consistent with most prominent SSc pathophysiologic processes. The damage and fibrosis of the muscle tissue and the reduced ability of the body to build and repair muscle lead to a loss of muscle mass and strength. Studies show that patients with SSc have a higher prevalence of myopenia than the general population, but the exact cause is not yet fully understood. Partially, this phenomenon could be attributed to the disrupted activity of fibro-adipogenic progenitors, driven by alterations in the skeletal muscle microenvironment of SSc patients. These changes are also reflected in shifts in myokine secretion.

The correct balance between reactive oxygen species and antioxidant defense in an organism is disturbed in oxidative stress. To assess oxidative balance in 36 SSc patients and 26 healthy controls (HCs), we measured reactive oxidative metabolites (ROMs), total antioxidant capacity (TAC), lipid peroxidation (measuring 4-HNE), and DNA oxidative damage (measuring 8-OHdG) in serum. Furthermore, DNA breaks in leukocytes of 35 SSc patients and 32 HCs were evaluated using COMET. While we report high ROMs for both SSc patients and age/sex matched HC samples, there was a significant increase in TAC in SSc patients as compared to HCs, and thus also a significantly higher oxidative stress index in SSc patients. TAC was significantly higher in SSc patients with ILD and gastrointestinal involvement, as well as in patients with anti-topoisomerase antibodies. We observe no difference in serum lipid peroxidation status or oxidative DNA damage. However, SSc patients had significantly more leukocyte DNA breaks than HCs; the most damage was observed in patients treated with immunosuppressives. Thus, our study confirms presence of oxidative stress and increased DNA damage in leukocytes of SSc patients; however, it points toward increased antioxidant capacity, which needs to be further studied.

Understanding the tissue changes and molecular mechanisms of preclinical models is essential for creating an optimal experimental design for credible translation into clinics. In our study, a chlorhexidine (CHX)-induced mouse model of peritoneal fibrosis was used to analyze histological and molecular/cellular alterations induced by 1 and 3 weeks of intraperitoneal CHX application. CHX treatment for 1 week already caused injury, degradation, and loss of mesothelial cells, resulting in local inflammation, with the most severe structural changes occurring in the peritoneum around the ventral parts of the abdominal wall. The local inflammatory response in the abdominal wall showed no prominent differences between 1 and 3 weeks. We observed an increase in polymorphonuclear cells in the blood but no evidence of systemic inflammation as measured by serum levels of serum amyloid A and interleukin-6. CHX-induced fibrosis in the abdominal wall was more pronounced after 3 weeks, but the gene expression of fibrotic markers did not change over time. Complement system molecules were strongly expressed in the abdominal wall of CHX-treated mice. To conclude, both histological and molecular changes were already present in week 1, allowing examination at the onset of fibrosis. This is crucial information for refining further experiments and limiting the amount of unnecessary animal suffering.

Monocytes are known to be implicated in the pathogenesis of systemic sclerosis (SSc), as they exert prominent migratory, adhesive, and chemotactic properties. The aim of our study was to characterize the surface expression of adhesion/chemotactic molecules (CD62L, CD11b, CCR2, CCR5) on the SSc monocytes and determine correlations with the clinical presentation of SSc. We included 38 SSc patients and 36 healthy age-and sex-matched controls. Isolated monocytes, as well as in vitro serum-treated monocytes, were analyzed by flow cytometry; additionally, soluble CD62L was measured in serum. We found increased soluble CD62L in the SSc serum samples and increased CD62L on the surface of the SSc monocytes in the in the same set of patients. Among samples with determined SSc-specific autoantibodies, the surface CD62L was the lowest in patients positive for anti-PM/Scl autoantibodies and the highest in patients with anti-topoisomerase I autoantibodies (ATA). The treatment of isolated healthy monocytes with ATA-positive SSc serum resulted in increased surface CD62L expression. Moreover, surface CCR5 was reduced on the monocytes from SSc patients with interstitial lung disease but also, along with CCR2, negatively correlated with the use of analgesics/anti-inflammatory drugs and immunosuppressants. In conclusion, increased CD62L on SSc monocytes, particularly in ATA-positive patients, provides new insights into the pathogenesis of SSc and suggests CD62L as a potential therapeutic target.

Deregulation of adiponectin is found in systemic autoimmune rheumatic diseases (SARDs). Its expression is downregulated by various inflammatory mediators, but paradoxically, elevated serum levels are present in SARDs with high inflammatory components, such as rheumatoid arthritis and systemic lupus erythematosus. Circulating adiponectin is positively associated with radiographic progression in rheumatoid arthritis as well as with cardiovascular risks and lupus nephritis in systemic lupus erythematosus. However, in SARDs with less prominent inflammation, such as systemic sclerosis, adiponectin levels are low and correlate negatively with disease activity. Regulators of adiponectin gene expression (PPAR-γ, Id3, ATF3, and SIRT1) and inflammatory cytokines (interleukin 6 and tumor necrosis factor α) are differentially expressed in SARDs and could therefore influence total adiponectin levels. In addition, anti-inflammatory therapy could also have an impact, as tocilizumab treatment is associated with increased serum adiponectin. However, anti-tumor necrosis factor α treatment does not seem to affect its levels. Our review provides an overview of studies on adiponectin levels in the bloodstream and other biological samples from SARD patients and presents some possible explanations why adiponectin is deregulated in the context of therapy and gene regulation.