Rui Seabra Ferreira Junior

Leishmaniasis and Chagas disease are neglected tropical diseases that continue to pose significant public health challenges, highlighting the need for new therapeutic strategies. Brazilian snake venoms represent a valuable and underexplored source of bioactive molecules with diverse pharmacological activities and promising therapeutic potential. In this context, the present study aimed to investigate the in vitro antiprotozoal potential of venoms from Bothrops and Crotalus species, including Bothrops jararacussu, Bothrops pauloensis, Bothrops alternatus, Bothrops leucurus, Bothrops atrox, Bothrops jararaca, Crotalus durissus terrificus, and Crotalus durissus ruruima, metalloprotease (MTL)- and crotoxin (CTX)-enriched, against Leishmania spp. and Trypanosoma cruzi. Crude venom protein profiles were analyzed by SDS-PAGE, and cytotoxicity was assessed in differentiated C2C12 myotubes and murine peritoneal macrophages. Antiprotozoal activity was evaluated against extracellular parasite forms, including promastigotes of Leishmania amazonensis and Leishmania infantum and epimastigotes of T. cruzi. Venoms exhibiting the highest selectivity indices (SIs), calculated using murine macrophage cytotoxicity data, were further tested against intracellular amastigotes of L. amazonensis. Among the tested samples, B. jararacussu venom showed activity against promastigotes of both L. amazonensis (IC₅₀ = 2.9 µg mL⁻¹) and L. infantum (IC₅₀ = 2.8 µg mL⁻¹), as well as in epimastigotes of T. cruzi (IC₅₀ = 15.5 µg mL⁻¹). The MTLand CTX pools from C. d. ruruima venom exhibited the highest activity against promastigotes of L. amazonensis, with IC₅₀ values of 1.6 and 3.8 µg mL⁻¹, respectively. Against intracellular amastigotes, MTL and CTX showed IC₅₀ values of 4.1 and 2.5 µg mL⁻¹, respectively, with selectivity indices (SIs) of 73.1 and 120, respectively. Overall, these findings provide preliminary evidence for the antiparasitic potential of snake venom-derived molecules, supporting further characterization and in vivo evaluation.

Type 1 diabetes mellitus (DM1) is characterized by autoimmune destruction of pancreatic β-cells, resulting in insulin deficiency and persistent hyperglycemia, which impair bone metabolism and compromise post-extraction alveolar bone healing. Heterologous fibrin biopolymer (HFB) has previously demonstrated biocompatibility, biodegradability, bioactivity, and osteoconductive properties under normoglycemic conditions. Therefore, the study investigated the association of HFB with post-extraction alveolar bone healing in streptozotocin-induced diabetic rats, using the diabetic blood clot as a biological control. Forty-eight adult male Wistar rats were induced to DM1 by a single intraperitoneal injection of streptozotocin (52 mg/kg). Animals were included after confirmation of hyperglycemia (fasting blood glucose ≥ 250 mg/dL) measured seven days after STZ administration: blood clot (BCG; n = 24) or HFB (HFBG; n = 24). Seven days after DM1 induction, the right maxillary incisor was extracted, and the sockets were filled according to group allocation. Animals were euthanized at 7, 14, and 42 days post-extraction. Fasting blood glucose levels were monitored, and pancreatic insulin immunohistochemistry was performed to characterize the diabetic condition. Alveolar bone healing was assessed by micro-CT, histological (HE), histomorphometric, and picrosirius red analyses. The diabetic phenotype was confirmed by persistent fasting hyperglycemia (260–589 mg/dL) and reduced pancreatic insulin immunostaining in β-cells. At 42 days, bone volume (BV) was 31.86% higher in the HFBG than in the BCG (p < 0.05). BCG exhibited higher trabecular number (Tb.N), while HFBG exhibited higher trabecular thickness (Tb.Th) (p < 0.05). Histologically, the HFBG shows a more mature, compact, and organized bone structure, whereas the BCG presents bone tissue with a more trabecular and immature architecture. HFBG showed the lowest percentage of thin fibers at the late stage, whereas BCG maintained similar values from 14 to 42 days (p < 0.05). These findings suggest that HFB was associated with favorable changes in selected late-stage parameters of post-extraction alveolar bone healing in an STZ-induced diabetic model.

The study evaluated bone repair in tibial defects of Wistar rats treated with 45S5 bioactive glass, either alone or combined with lyophilized heterologous fibrin biopolymer (HFB) and/or photobiomodulation therapy (PBM). Thirty-five animals were randomly assigned to five groups: control (CG), Bioactive glass (BG), Bioactive glass + HFB (BFG), Bioactive glass + PBM (BPG), and Bioactive glass + HFB + PBM (BFPG). After 42 days, the samples were analyzed by micro-computed tomography, histology (Hematoxylin–Eosin, Masson’s Trichrome, and Picrosirius Red), and histomorphometry. Histological and micro-CT findings demonstrated improved defect closure and better matrix organization in the BG and BFG groups. Histomorphometric analysis revealed significant differences among the groups (ANOVA, p < 0.0001), with the BG group showing the highest percentage of new bone formation (40.35 ± 4.14%), significantly higher than the BPG and BFPG groups. The addition of HFB did not impair bone repair and yielded intermediate results, whereas PBM did not demonstrate a positive effect on bone regeneration at the 42-day time point under the parameters used in this study. It can be concluded that bioactive glass, especially when used alone or in combination with heterologous fibrin biopolymer, promoted superior bone regeneration, while its association with photobiomodulation did not demonstrate additional benefit at 42 days.

Treating fractures involving complex bone defects remains a major challenge in regenerative medicine. Additive manufacturing enables the fabrication of patient-specific implants, while surface anodization may enhance osseointegration by improving cell adhesion at the bone–implant interface. This study evaluated the feasibility of porous Ti-6Al-4V implants produced by additive manufacturing and surface-modified by anodization for repairing critical-sized femoral defects. Eighty rats were assigned to four groups: control (no graft), non-anodized Ti-6Al-4V implants, nanoporous implants, and nanotubular implants. After six weeks, bone regeneration and mechanical performance were assessed. Newly formed bone volume was significantly higher in the implanted groups compared to control (24.62 ± 3.11%), reaching 47.25 ± 3.92% (non-anodized), 58.20 ± 5.39% (nanoporous), and 40.72 ± 2.22% (nanotubular). Bone strength was also greater in implanted groups (150.27 ± 2.94 N, 151.98 ± 10.37 N, and 156.59 ± 4.95 N, respectively) compared to control (128.16 ± 2.17 N), with no significant differences among treated groups. No signs of implant rejection or inflammation were observed, indicating good biocompatibility. Anodized surfaces demonstrated enhanced osteogenic performance, particularly in the nanoporous group. These findings indicate that anodized porous Ti-6Al-4V implants produced by additive manufacturing combine biological compatibility with mechanical stability, supporting their potential application in bone reconstruction therapies.

Currently, commercially available pain medications can cause adverse effects. Within this framework, researchers have been exploring new drug candidates derived from animal venoms and toxins. The objective of this study was to investigate the number of molecules with potential for pain relief derived from animal venoms and toxins, which could potentially contribute to the development of new biopharmaceuticals. We conducted a literature search in January 2025, covering the period from 1960 to 2025, in two Latin American and nine international scientific databases. The results consisted of 212 articles selected for review. From these articles, 152 toxins and venoms with analgesic potential were identified and classified into 14 different types of pharmacological targets. The peptides investigated, with masses between 500 Da and 5000 Da, are strong candidates for alternative biopharmaceuticals. Most of the toxins found interact with ion channels, representing an alternative to commercially available drugs.

Fisheries bycatch, while representing a major ecological concern due to the incidental capture of non-target species, also constitutes an underexplored source of marine biomass with biotechnological potential. This study aimed to generate and characterize bioactive peptides from the muscle tissue of three common bycatch species from the Brazilian coast: Paralonchurus brasiliensis, Micropogonias furnieri, and Hepatus pudibundus. Muscle homogenates were hydrolyzed using either Alcalase or Protamex to produce peptide-rich hydrolysates, which were analyzed through SDS-PAGE, HPLC-UV, MALDI-TOF, and LC-MS/MS. De novo sequencing and bioinformatic analyses predicted bioactivities that were subsequently validated by in vitro assays. The results demonstrated that enzyme selection strongly influenced both peptide profiles and bioactivity. The Protamex hydrolysate of P. brasiliensis (PBP) exhibited potent antifungal activity, inhibiting Candida albicans growth by 81%, whereas the Alcalase hydrolysate (PBA) showed moderate inhibition of Staphylococcus aureus (29%). No significant effect was observed against Escherichia coli. Overall, this study highlights a sustainable strategy for the valorization of fisheries bycatch through the production of bioactive marine peptides and identifies P. brasiliensis hydrolyzed with Protamex as a promising source of anti-Candida peptides for pharmaceutical and nutraceutical applications.

Translational research utilizing mass spectrometry to identify and validate biomarkers requires high-quality samples to maintain the integrity of research results. Key steps, including study design and sample/data quality control, are often overlooked or undervalued, which can compromise the consistency, accuracy, and verifiability of scientific and clinical outcomes. This is a prospective, longitudinal, multicenter cohort clinical trial that is recruiting participants who are victims of snakebite in Brazil and healthy individuals. Previously published studies on clinical trials and clinical-epidemiological research related to snakebites have identified universal measures and their categories, which were used to develop the study design and prepare the Case Report Forms. The biorepository presents a collection of clinical and epidemiological data, images of clinical manifestations, results of laboratory tests, and biological samples (serum and plasma in the presence of EDTA and sodium citrate). This article presents recommendations for essential steps in designing and implementing a mass spectrometry-based biomarker and mechanistic study focused on snakebite envenomation. We outline critical reporting models for conducting each phase of clinical data acquisition, such as collecting biological materials (serum and blood plasma) and processing samples to minimize the study’s pre-analytical variables. The guidelines provided, covering everything from study design to implementation and data interpretation, serve as a reference to increasing the rigor and reproducibility of clinical proteomics studies. The results of this study can transcend basic research, connecting technological development to real clinical application, optimizing diagnosis and monitoring, but also contributing to reducing the economic burden, morbidity and mortality associated with these accidents.

Bone regeneration remains a clinical challenge, particularly in critical-size defects, motivating the investigation of biomaterials and adjuvant therapies that may support tissue repair. This experimental study evaluated bone healing in critical-size calvarial defects created in rats, using different combinations of regenerative strategies, including heterologous fibrin biopolymer gel, bovine cortical bone biological membrane, and photobiomodulation. Standardized 5.0 mm calvarial defects were surgically created in sixty Wistar rats, which were randomly allocated into six experimental groups according to the filling material and the application or absence of photobiomodulation. The treatments included clot alone, fibrin biopolymer gel, biological membrane, photobiomodulation, or their respective combinations. Animals were euthanized at 14 or 42 days, and bone repair was evaluated by histomorphometric analysis. At 14 days, differences in the extent of newly formed bone were observed among the experimental groups, with higher bone formation values detected in groups receiving combined treatments and lower values in groups treated with fewer regenerative components. At 42 days, all groups showed progression of bone repair, with greater bone formation observed in groups in which a biological membrane was used, regardless of photobiomodulation. Overall, the findings indicate that the association of different regenerative approaches was related to variations in bone repair patterns over time, suggesting that photobiomodulation, when applied in combination with biomaterials, may be associated with differences in early bone healing, without implying a direct causal effect.

Background: Although bone tissue possesses inherent regenerative capacity, critical-sized defects require grafts for complete functional repair. This in vivo study evaluated the bone repair process using laser photobiomodulation therapy (PBM) in defects filled with a combination of hydroxyapatite, β-tricalcium phosphate and heterologous fibrin biopolymer (HFB). Methods: Thirty male rats were divided into three groups: biomaterial alone (BG), biomaterial + HFB (BBG), and biomaterial + HFB + PBM (BBPG). A 5-mm circular calvarial osteotomy was performed and filled according to each protocol. In BBPG, an 830-nm laser was applied immediately post-surgery and three times weekly until euthanasia at 14 or 42 days. Analyses included micro-CT, histomorphology, histomorphometry, and polarized light microscopy of collagen fibers. Results: Micro-CT showed centripetal bone regeneration restricted to defect margins, with biomaterial particles persisting centrally. Histologically, new bone progressed from immature trabecular architecture at day 14 to a mature lamellar conformation by day 42, notably in BBPG. All groups showed a significant temporal increase in new bone percentage. BBPG demonstrated superior bone growth at 42 days (26.64 ± 2.15%) compared to BG (14.85 ± 1.63%) and BBG (20.05 ± 1.70%). The birefringence of the collagen fibers showed a color transition from red to yellowish-green during the analyzed periods. Conclusion: The combination of the biomaterial, fibrin biopolymer and photobiomodulation significantly enhanced bone defect repair and matrix maturation without barrier membranes, presenting high translational potential for cost-effective clinical applications in regenerative medicine.