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- A new bioactive dermal substitute for wound healing and skin regenerationPublication . Rosadas, Marta; Sousa, Teresa; Reis, Mariana; Sousa, Clara; Sousa, Alda; Sánchez Espinel, Christian; Peleteiro, Mercedes; González-Fernández, África; Ribeiro, Viviana P.; Oliveira, Ana LeiteAim: Rabbit skin is an abundant agri-food by-product with interesting properties to be up-cycled into a xenogeneic dermal substrate for skin and regeneration. When decellularized, rabbit dermis preserves collagen–elastin components that can guide cell behavior. However, decellularization conditions can also influence the preservation of tissue architecture and may introduce immunogenic triggers such as damage-associated molecular patterns (DAMPs). This work aimed to develop low-immunogenicity decellularized dermal matrices (dDMs) using rabbit skin as by- product. Method: dDMs were generated using optimized chemical decellularization protocols and evaluated for structural and biochemical integrity using SEM, tensile testing, FTIR, proteomics, and DNA, GAGs, collagen, and elastin quantification. Immunogenicity was assessed throughendotoxin analysis and by exposing human peripheral blood mononuclear cells (PBMCs) to the matrices to measure complement activation, ROS, apoptosis, activation markers, and cytokine release. The ability of dDMs to support human dermal fibroblasts (hDFs) and keratinocytes (HaCaTs) was examined over 14 days using Alamar Blue, BrdU, SEM, and DAPI/phalloidin staining. Results/Discussion: dRDMs preserved native collagen–elastin architecture, and GAG levels were comparable to human dermis. Residual DNA confirmed effective decellularization. No significant immune activation occurred: ROS and apoptosis were absent, and PBMC activation matched controls with only mild monocyte and B-cell responses. Cytokine release indicated modest inflammatory signaling induction. Interestingly, matrices with lower DNA content triggered stronger immune responses, suggesting biocompatibility is influenced more by processing-related factors (detergent residues or DAMPs) than by DNA levels. hDF and HaCaT adhesion, viability, and proliferation were maintained for 14 days. Conclusion: dRDMs showed favorable structural, biochemical, and immunological profiles and supported dermo-epidermal cell growth, demonstrating potential as bioactive dermal substitutes for skin regeneration.
- Time-dependent accumulation of biogenic amines and microbial succession during dry-aging of beef: safety implicationsPublication . Ribeiro, Ana J.; Milheiro, Juliana; Nunes, Fernando M.; Carvalho, Teresa B. de; Barbosa, Joana B.; Silva, Filipe; Teixeira, Paula; Saraiva, Cristina M.Dry-aging of beef under controlled temperature, humidity and airflow reshapes the surface microbiota and may influence biogenic amine (BA) accumulation. In this study, culture-based enumeration, 16 S rRNA gene profiling of combined crust + inner meat, and validated HPLC quantification of BAs were integrated to track safety- and quality-relevant changes over 60 days. Sequencing showed Pseudomonadota and Bacillota consistently >95 % of reads; communities were dominated by Pseudomonas, Brochothrix and Psychrobacter, with Acinetobacter rising at mid-aging. Alpha diversity peaked at day 35 (Shannon 1.33???2.12; overall P = 0.0225; day 35 vs day 1, adjusted P = 0.0069) and became heterogeneous by day 60. Culture confirmed a surface-led, aerobic succession: crust counts increased and Pseudomonas reached 5.6 log CFU/g at day 60, whereas inner-muscle counts declined across groups; pathogens were not detected. In the inner meat, cadaverine rose from non-detectable to 31 ± 37 mg/kg at day 60 P < 0.001), spermine peaked at day 35 (52 ± 14 mg/kg; P < 0.001), while histamine remained <5 mg/kg and other BAs showed no significant change. All inner-meat BAs remained below commonly cited concern ranges, though late-stage variance indicates sporadic hot spots, likely reflecting diffusion from the crust and proteolysis-enabled precursor supply. Integrating microbes and metabolites identified two ecological–metabolic tendencies linking psychrotrophic genera with polyamines or diamines. In practice, day 35 emerges as a quality “sweet spot,” whereas approaching day 60 warrants tighter surface management and targeted monitoring of pseudomonads, Enterobacteriaceae and cadaverine/putrescine.