Danielle Cabral Bonfim

Background/Objectives: Bone fractures represent a growing public health concern worldwide, yet national epidemiological assessments remain limited in Brazil. Understanding temporal trends, demographic disparities, and geographic heterogeneity is essential to guide prevention, resource allocation, and trauma-care planning. To characterize the epidemiological profile of bone-fracture-related hospitalizations and mortality in Brazil between 2015 and 2024, analyzing trends by sex, age, fracture type, and geographic and ethnic distribution. Methods: An epidemiological, observational, descriptive, and population-based ecological study was conducted using Hospital Information System of the Unified Health System SIH/SUS and IBGE data. Hospitalization rates, case fatality rates (CFR), relative risks, odds ratios, and Years of Life Lost (YLL) were calculated. Temporal trends were evaluated using Annual Percent Change (APC). Results: Other limb fractures were the most frequent injuries, while femur fractures showed the highest lethality. Men had nearly twice the hospitalization rate of women, driven by high-energy trauma in adults aged 20–59 years, whereas women experienced a sharp increase in femur-fracture admissions at older ages. Skull, facial, and thorax/pelvis fractures contributed disproportionately to premature mortality. Marked geographic and ethnic disparities were observed, with higher burdens in the North/Northeast and predominance among Brown and Indigenous populations. Conclusions: Fracture-related hospitalizations in Brazil have increased consistently, with distinct epidemiological patterns across demographic and regional groups. These findings highlight the need for targeted prevention and improved trauma-care strategies.

Bone tissue engineering has evolved from the passive use of structural fillers to a sophisticated discipline that actively harnesses endogenous regenerative mechanisms. At the core of this paradigm shift lies the immune system, particularly macrophages, as dynamic regulators of repair. Rather than merely suppressing inflammation, contemporary biomaterials are designed to modulate its trajectory, orchestrating the timely transition from a pro-inflammatory (M1) phenotype toward a pro-resolutive (M2) state. This review synthesizes a decade of progress in macrophage-centered bioengineering, focusing on strategies validated in preclinical in vivo models to ensure biological relevance and translational potential. These approaches are categorized across three levels of increasing complexity: (i) tailored biomaterials, where intrinsic physical and chemical properties direct cell fate; (ii) hybrid scaffolds, integrating diverse material classes and advanced delivery systems; and (iii) 3D-printed bioactive constructs, combining structural precision with ions, drugs, or cellular components. Together, these strategies define the emerging field of osteoimmunomodulation, characterized by the design of immuno-instructive materials. By critically evaluating the evolution of these principles, including their translational barriers and potential pitfalls, this review provides key insights into the field’s progression, identifying effective strategies to guide the development of next-generation bone therapies.

Background: Bone fractures represent a growing public health concern worldwide, yet national epidemiological assessments remain limited in Brazil. Understanding temporal trends, demographic disparities, and geographic heterogeneity is essential to guide prevention, resource allocation, and trauma-care planning. Objective: To characterize the epidemiological profile of bone-fracture–related hospitalizations and mortality in Brazil between 2015 and 2024, analyzing trends by sex, age, fracture type, and geographic and ethnic distribution. Methods: An epidemiological, observational, descriptive, and population-based ecological study was conducted using SIH/SUS and IBGE data. Hospitalization rates, case fatality rates (CFR), relative risks, odds ratios, and Years of Life Lost (YLL) were calculated. Temporal trends were evaluated using Annual Percent Change (APC). Results: Other limb fractures were the most frequent injuries, while femur fractures showed the highest lethality. Men had nearly twice the hospitalization rate of women, driven by high-energy trauma in adults aged 20–59 years, whereas women experienced a sharp increase in femur-fracture admissions at older ages. Skull, facial, and thorax/pelvis fractures contributed disproportionately to premature mortality. Marked geographic and ethnic disparities were observed, with higher burdens in the North/Northeast and predominance among Brown and Indigenous populations. Conclusion: Fracture-related hospitalizations in Brazil have increased consistently, with distinct epidemiological patterns across demographic and regional groups. These findings highlight the need for targeted prevention and improved trauma-care strategies. Key Messages: This study investigated national temporal trends and demographic, geographic, and ethnic disparities in bone-fracture–related hospitalizations and mortality in Brazil from 2015 to 2024. We found a sustained increase in fracture-related hospitalizations, with femur fractures showing the greatest lethality and fractures of other limb bones accounting for the highest volume, and marked disparities by sex, age, region, and ethnicity. These findings are important because they provide the first comprehensive national overview of fracture burden in Brazil and offer evidence to inform targeted prevention policies, equitable resource allocation, and trauma-care planning.

Background: The Wnt/β-catenin signaling pathway plays a pivotal role in embryonic development, maintenance of the central nervous system, and the formation of neuronal circuits. Disruption of this pathway is closely associated with oncogenesis and neurodegenerative diseases, notably Alzheimer’s disease. Flavonoids such as quercetin derivatives have emerged as promising neuroprotective agents. This study investigates the impact of 3-O-methylquercetin (3OMQ), a methylated quercetin metabolite, on Wnt/β-catenin signaling and its potential relevance in neurodegenerative disease models. Methods: The ability of 3OMQ to modulate Wnt/β-catenin activity was analyzed using a luciferase-based reporter assay in both neural and non-neural cell lines. Cell viability assays evaluated cytotoxicity at various concentrations. We mapped 3OMQ activity within the pathway using targeted cell signaling experiments. Docking and molecular dynamics simulations suggested glycogen synthase kinase 3β (GSK3β) as a putative target of 3OMQ. Finally, we employed a mouse model of acute amyloid-β oligomer (AβO) toxicity to assess the in vivo effects of 3OMQ on spatial memory and Wnt-related gene expression. Results: We compared the flavonoids quercitrin, quercetin, and 3-O-methylquercitrin (3OMQ) with pharmacologically active compounds in a gene reporter assay (TOPFLASH) using Wnt-sensitive RKO cells treated with Wnt3a-conditioned medium. XAV-939 and PNU-74654 showed inhibitory activity, while BIO, CHIR99021, quercitrin, and 3OMQ enhanced the Wnt/β-catenin pathway. Notably, 3OMQ potentiated this pathway at concentrations 5–10 times lower than quercitrin and outperformed 1 μM BIO at 10 μM without cytotoxicity, highlighting its remarkable potency. Mechanistically, 3OMQ acts downstream of initial membrane activation and upstream of the β-catenin destruction complex. Consistently, molecular docking indicates a strong interaction with GSK3, a central regulator of the pathway. In adult mice, 3OMQ administration prevented AβO-induced recognition memory deficits and favored normalization of Wnt-related gene expression. Conclusions: These findings identify 3OMQ as a potent positive modulator of the Wnt/β-catenin pathway, with both in vitro and in vivo neuroprotective effects. Targeting Wnt signaling with compounds such as 3OMQ holds promise for maintaining neuronal health and developing therapeutic strategies for neurodegenerative conditions.

Daiana V. Lopes Alves, Cesar Claudio-da-Silva, Marcelo C. A. Souza, Rosa T. Pinho, Wellington Seguins da Silva, Periela S. Sousa-Vasconcelos, Radovan Borojevic, Carmen M. Nogueira, Hélio dos S. Dutra, Christina M. Takiya, Danielle C. Bonfim, Maria Isabel D. Rossi. IJSC 2023;16:425-37. https://doi.org/10.15283/ijsc22172

Objective: This review addresses the latest advances in research on the role of macrophages in fracture healing, exploring their relationship with failures in bone consolidation and the perspectives for the development of advanced and innovative therapies to promote bone regeneration. Background: The bone can fully restore its form and function after a fracture. However, the regenerative process of fracture healing is complex and is influenced by several factors, including macrophage activity. These cells have been found in the fracture site at all stages of bone regeneration, and their general depletion or the knockdown of receptors that mediate their differentiation, polarization, and/or function result in impaired fracture healing. Methods: The literature search was carried out in the PubMed database, using combinations of the keywords “macrophage”, “fracture healing, “bone regeneration”, and “bone repair”. Articles published within the last years (2017–2022) reporting evidence from in vivo long bone fracture healing experiments were included. Conclusions: Studies published in the last five years on the role of macrophages in fracture healing strengthened the idea that what appears to be essential when it comes to a successful consolidation is the right balance between the M1/M2 populations, which have different but complementary roles in the process. These findings opened promising new avenues for the development of several macrophage-targeted therapies, including the administration of molecules and/or biomaterials intended to regulate macrophage differentiation and polarization, the local transplantation of macrophage precursors, and the use of exosomes to deliver signaling molecules that influence macrophage activities. However, more research is still warranted to better understand the diversity of macrophage phenotypes and their specific roles in each step of fracture healing and to decipher the key molecular mechanisms involved in the in vivo crosstalk between macrophages and other microenvironmental cell types, such as endothelial and skeletal stem/progenitor cells.

Although several studies assess the biological effects of micro and titanium dioxide nanoparticles (TiO₂ NPs), the literature shows controversial results regarding their effect on bone cell behavior. Studies on the effects of nanoparticles on mammalian cells on two-dimensional (2D) cell cultures display several disadvantages, such as changes in cell morphology, function, and metabolism and fewer cell–cell contacts. This highlights the need to explore the effects of TiO₂ NPs in more complex 3D environments, to better mimic the bone microenvironment. This study aims to compare the differentiation and mineralized matrix production of human osteoblasts SAOS-2 in a monolayer or 3D models after exposure to different concentrations of TiO₂ NPs. Nanoparticles were characterized, and their internalization and effects on the SAOS-2 monolayer and 3D spheroid cells were evaluated with morphological analysis. The mineralization of human osteoblasts upon exposure to TiO₂ NPs was evaluated by alizarin red staining, demonstrating a dose-dependent increase in mineralized matrix in human primary osteoblasts and SAOS-2 both in the monolayer and 3D models. Furthermore, our results reveal that, after high exposure to TiO₂ NPs, the dose-dependent increase in the bone mineralized matrix in the 3D cells model is higher than in the 2D culture, showing a promising model to test the effect on bone osteointegration.

Bones have a significant regenerative capacity. However, fracture healing is a complex process, and depending on the severity of the lesions and the age and overall health status of the patient, failures can occur, leading to delayed union or nonunion. Due to the increasing number of fractures resulting from high-energy trauma and aging, the development of innovative therapeutic strategies to improve bone repair based on the combination of skeletal/mesenchymal stem/stromal cells and biomimetic biomaterials is urgently needed. To this end, the use of reliable animal models is fundamental to better understanding the key cellular and molecular mechanisms that determine the healing outcomes. Of all the models, the mouse is the preferred research model because it offers a wide variety of transgenic strains and reagents for experimental analysis. However, the establishment of fractures in mice may be technically challenging due to their small size. Therefore, this article aims to demonstrate the procedures for the surgical establishment of a diaphyseal femur fracture in mice, which is stabilized with an intramedullary wire and resembles the most common bone repair process, through cartilaginous callus formation.

Bone marrow stromal cells (BMSCs, also known as bone marrow mesenchymal stem cells) are a plastic-adherent heterogeneous cell population that contain inherent skeletal progenitors and a subset of multipotential skeletal stem cells (SSCs). Application of BMSCs in therapeutic protocols implies its isolation and expansion under good manufacturing practices (GMP). Here we describe the procedures we have found to successfully generate practical BMSCs numbers, with preserved biological potency.

The potential of stem cell-based therapy was accompanied by high expectations and led, consequently, to an increase in clinical translational investments. Mesenchymal stem/stromal cells (MSCs) became the cell-based product most experimentally studied worldwide. However, uncertainties about the mechanisms and the in vivo identity of MSCs impose concerns about their large-scale use in regenerative medicine. This review comprises a historical summary on MSC, a critical discussion about their identity and function, and the ongoing challenges for their use in therapy and tissue bioengineering. O potencial das células-tronco adultas para terapias celulares é cercado de grande expectativa e, consequentemente, levou a um aumento nos investimentos na clínica translacional. As células-tronco mesenquimais, também denominadas células mesenquimais do estroma (MSCs, Mesenchymal Stem/Stromal Cells) se tornaram o produto celular mais estudado experimentalmente em todo o mundo. Entretanto, incertezas a respeito das propriedades e da identidade in vivo das MSCs levantam questões sobre seu uso extenso em medicina regenerativa. Esta revisão compreende um breve histórico sobre as MSCs, uma análise crítica a respeito de sua identidade e função e os permanentes desafios para seu uso terapêutico em bioengenheria.