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Nanomaterials exhibit significant potential for stimulating immune responses, offering both local and systemic modulation across a variety of diseases. The lymphoid organs, such as the spleen and lymph nodes, are home to various immune cells, including monocytes and dendritic cells, which contribute to both the progression and prevention/treatment of diseases. Consequently, many nanomaterial formulations are being rationally designed to target these organs and engage with specific cell types, thereby inducing therapeutic and protective effects. In this review, we explore crucial cellular interactions and processes involved in immune regulation and highlight innovative nano-based immunomodulatory approaches. We outline essential considerations in nanomaterial design with an emphasis on their impact on biological interactions, targeting capabilities, and treatment efficacy. Through selected examples, we illustrate the strategic targeting of therapeutically active nanomaterials to lymphoid organs and the subsequent immunomodulation for infection resistance, inflammation suppression, self-antigen tolerance, and cancer immunotherapy. Additionally, we address current challenges, discuss emerging topics, and share our outlook on future developments in the field.
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Imunomodulação , Inflamação , Nanoestruturas , Neoplasias , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Nanoestruturas/química , Inflamação/tratamento farmacológico , Inflamação/imunologia , Imunomodulação/efeitos dos fármacos , Animais , Imunoterapia , Tecido Linfoide/imunologia , Tecido Linfoide/efeitos dos fármacosRESUMO
Wound infections, especially those caused by pathogenic bacteria, present a considerable public health concern due to associated complications and poor therapeutic outcomes. Herein, we developed antibacterial nanoparticles, namely, PGTP, by coordinating guanidine derivatives with a porphyrin-based sonosensitizer. The synthesized PGTP nanoparticles, characterized by their strong positive charge, effectively disrupted the bacterial biosynthesis process through charge interference, demonstrating efficacy against both Gram-negative and Gram-positive bacteria. Additionally, PGTP nanoparticles generated reactive oxygen species under ultrasound stimulation, resulting in the disruption of biofilm integrity and efficient elimination of pathogens. RNA-seq analysis unveiled the detailed mechanism of wound healing, revealing that PGTP nanoparticles, when coupled with ultrasound, impair bacterial metabolism by interfering with the synthesis and transcription of amino acids. This study presents a novel approach to combatting wound infections through ultrasound-driven charge-interfering therapy, facilitated by advanced antibacterial nanomaterials.
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Antibacterianos , Biofilmes , Nanopartículas , Infecção dos Ferimentos , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/uso terapêutico , Infecção dos Ferimentos/tratamento farmacológico , Infecção dos Ferimentos/microbiologia , Nanopartículas/química , Nanopartículas/uso terapêutico , Biofilmes/efeitos dos fármacos , Animais , Camundongos , Ondas Ultrassônicas , Espécies Reativas de Oxigênio/metabolismo , Cicatrização/efeitos dos fármacos , Humanos , Porfirinas/química , Porfirinas/farmacologia , Porfirinas/uso terapêutico , Terapia por Ultrassom/métodos , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacosRESUMO
The University of Michigan has played an important role in advancing gender-affirming surgery programs in the United States. The University of Michigan was home to a little-known gender identity clinic shortly after the opening of the first such clinic at Johns Hopkins. Since 1995, the University of Michigan Comprehensive Services Program (UMCGSP) has been continually offering surgical services to transgender and gender diverse patients. Here, we present the history of both programs, drawn from program documents and oral history, and explore their implications for the future sustainability of gender-affirming surgery programs. The original gender identity clinic opened in 1968, and operated in a multidisciplinary fashion, similar to other clinics at the time. Eventually, the clinic was closed due to disinvestment and lack of sufficient providers to maintain the program, problems which are being increasingly recognized as barriers for similar programs. The modern program, UMCGSP is perhaps the longest continually running gender-affirming surgical program at an academic center. In spite of challenges, key investments in education, statewide community engagement, and the development of a comprehensive care model have helped UMCGSP avoid the pitfalls of the earlier clinic and remain relevant throughout its nearly 30-year history. In the face of rising challenges to gender-affirming care in the United States, much can be learned from the sustainability of the UMCGSP. Institutions seeking to maintain gender-affirming surgery programs should ensure the availability of comprehensive care and promote the education of the health care workforce.
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Brachytherapy is an established treatment modality that has been globally utilized for the therapy of malignant solid tumors. However, classic therapeutic sealed sources used in brachytherapy must be surgically implanted directly into the tumor site and removed after the requisite period of treatment. In order to avoid the trauma involved in the surgical procedures and prevent undesirable radioactive distribution at the cancerous site, well-dispersed radiolabeled nanomaterials are now being explored for brachytherapy applications. This emerging field has been coined "nanoscale brachytherapy". Despite present-day advancements, an ongoing challenge is obtaining an advanced, functional nanomaterial that concurrently incorporates features of high radiolabeling yield, short labeling time, good radiolabeling stability, and long tumor retention time without leakage of radioactivity to the nontargeted organs. Further, attachment of suitable targeting ligands to the nanoplatforms would widen the nanoscale brachytherapy approach to tumors expressing various phenotypes. Molecular imaging using radiolabeled nanoplatforms enables noninvasive visualization of cellular functions and biological processes in vivo. In vivo imaging also aids in visualizing the localization and retention of the radiolabeled nanoplatforms at the tumor site for the requisite time period to render safe and effective therapy. Herein, we review the advancements over the last several years in the synthesis and use of functionalized radiolabeled nanoplatforms as a noninvasive substitute to standard brachytherapy sources. The limitations of present-day brachytherapy sealed sources are analyzed, while highlighting the advantages of using radiolabeled nanoparticles (NPs) for this purpose. The recent progress in the development of different radiolabeling methods, delivery techniques and nanoparticle internalization mechanisms are discussed. The preclinical studies performed to date are summarized with an emphasis on the current challenges toward the future translation of nanoscale brachytherapy in routine clinical practices.
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Cancer represents a serious disease with significant implications for public health, imposing substantial economic burden and negative societal consequences. Compared to conventional cancer treatments, such as surgery and chemotherapy, energy-based therapies (ET) based on athermal and thermal ablation provide distinct advantages, including minimally invasive procedures and rapid postoperative recovery. Nevertheless, due to the complex pathophysiology of many solid tumors, the therapeutic effectiveness of ET is often limited. Nanotechnology offers unique opportunities by enabling facile material designs, tunable physicochemical properties, and excellent biocompatibility, thereby further augmenting the outcomes of ET. Numerous nanomaterials have demonstrated the ability to overcome intrinsic therapeutic resistance associated with ET, leading to improved antitumor responses. This comprehensive review systematically summarizes the underlying mechanisms of ET-associated resistance (ETR) and highlights representative applications of nanoplatforms used to mitigate ETR. Overall, this review emphasizes the recent advances in the field and presents a detailed account of novel nanomaterial designs in combating ETR, along with efforts aimed at facilitating their clinical translation.
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Hipertermia Induzida , Nanoestruturas , Neoplasias , Humanos , Nanomedicina/métodos , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Nanotecnologia/métodos , Nanoestruturas/uso terapêuticoRESUMO
Silver sulfide nanoparticles (Ag2S-NP) hold promise for various optical-based biomedical applications, such as near-infrared fluorescence (NIRF) imaging, photoacoustics (PA), and photothermal therapy (PTT). However, their NIR absorbance is relatively low, and previous formulations are synthesized using toxic precursors under harsh conditions and are not effectively cleared due to their large size. Herein, sub-5 nm Ag2S-NP are synthesized and encapsulated in biodegradable, polymeric nanoparticles (AgPCPP). All syntheses are conducted using biocompatible, aqueous reagents under ambient conditions. The encapsulation of Ag2S-NP in polymeric nanospheres greatly increases their NIR absorbance, resulting in enhanced optical imaging and PTT effects. AgPCPP nanoparticles exhibit potent contrast properties suitable for PA and NIRF imaging, as well as for computed tomography (CT). Furthermore, AgPCPP nanoparticles readily improve the conspicuity of breast tumors in vivo. Under NIR laser irradiation, AgPCPP nanoparticles significantly reduce breast tumor growth, leading to prolonged survival compared to free Ag2S-NP. Over time, AgPCPP retention in tissues gradually decreases, without any signs of acute toxicity, providing strong evidence of their safety and biodegradability. Therefore, AgPCPP may serve as a "one-for-all" theranostic agent that degrades into small components for excretion after fulfilling diagnostic and therapeutic tasks, offering good prospects for clinical translation.
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Neoplasias da Mama , Nanopartículas , Humanos , Feminino , Neoplasias da Mama/terapia , Fototerapia/métodos , Linhagem Celular Tumoral , Nanomedicina Teranóstica/métodos , PolímerosRESUMO
The rapid progress in the development of COVID-19 mRNA vaccines during the initial year of the pandemic has highlighted the significance of lipid nanoparticles in therapeutic delivery. Various lipid types have been investigated for the effective delivery of mRNA, each with unique functions and versatile applications. These range from their use in cancer immunotherapy and gene editing to their role in developing vaccines against infectious diseases. Nonetheless, continued exploration of novel lipids and synthetic approaches is necessary to further advance the understanding and expand the techniques for optimizing mRNA delivery. In this work, new lipids derived from FDA-approved soybean oil are facilely synthesized and these are employed for efficient mRNA delivery. EGFP and Fluc mRNA are used to evaluate the delivery efficacy of the lipid formulations both in vitro and in vivo. Furthermore, organ-specific targeting capabilities are observed in certain formulations, and their outstanding performance is demonstrated in delivering Cre mRNA for gene editing. These results showcase the potential of soybean oil-derived lipids in mRNA delivery, offering utility across a broad spectrum of bioapplications.
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Nanopartículas , Vacinas , RNA Mensageiro/genética , Óleo de Soja , Edição de Genes/métodosRESUMO
Acute respiratory disease syndrome (ARDS) is a common critical disease with high morbidity and mortality rates, yet specific and effective treatments for it are currently lacking. ARDS was especially apparent and rampant during the COVID-19 pandemic. Excess reactive oxygen species (ROS) production and an uncontrolled inflammatory response play a critical role in the disease progression of ARDS. Herein, we developed molybdenum nanodots (MNDs) as a functional nanomaterial with ultrasmall size, good biocompatibility, and excellent ROS scavenging ability for the treatment of acute lung injury (ALI). MNDs, which were administered intratracheally, significantly ameliorated lung oxidative stress, inflammatory response, protein permeability, and histological severity in ALI mice without inducing any safety issues. Importantly, transcriptomics analysis indicated that MNDs protected lung tissues by inhibiting the activation of the Nod-like receptor protein 3 (NLRP3)-dependent pyroptotic pathway. This work presents a promising therapeutic agent for patients suffering from ARDS.
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Lesão Pulmonar Aguda , Síndrome do Desconforto Respiratório , Humanos , Camundongos , Animais , Espécies Reativas de Oxigênio/metabolismo , Molibdênio/farmacologia , Molibdênio/uso terapêutico , Molibdênio/metabolismo , Pandemias , Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/metabolismo , Lesão Pulmonar Aguda/patologia , Pulmão/metabolismo , Síndrome do Desconforto Respiratório/tratamento farmacológico , Síndrome do Desconforto Respiratório/metabolismo , Síndrome do Desconforto Respiratório/patologia , Lipopolissacarídeos/farmacologiaRESUMO
The transmembrane glycoprotein adhesion molecule CD146 is overexpressed in a wide variety of cancers. Through molecular imaging, a specific biomarker's expression and distribution can be viewed in vivo non-invasively. Radionuclide-labeled monoclonal antibodies or relevant fragments that target CD146 may find potential applications in cancer imaging, thereby offering tremendous value in cancer diagnosis, staging, prognosis evaluation, and prediction of drug resistance. This review discusses the recent developments of CD146-targeted molecular imaging via nuclear medicine, especially in malignant melanoma, brain tumor, lung cancer, liver cancer, breast cancer, and pancreatic cancer. Many studies have proved that CD146 targeting may present a promising strategy for cancer theranostics.
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Silver sulfide nanoparticles (Ag 2 S-NP) have been proposed for various optical-based biomedical applications, such as near-infrared fluorescence (NIRF) imaging, photoacoustics (PA) and photothermal therapy (PTT). However, their absorbance is relatively low in the NIR window used in these applications, and previous formulations were synthesized using toxic precursors under harsh conditions and have clearance issues due to their large size. Herein, we synthesized sub-5 nm Ag 2 S-NP and encapsulated them in biodegradable, polymeric nanoparticles (AgPCPP). All syntheses were conducted using biocompatible reagents in the aqueous phase and under ambient conditions. We found that the encapsulation of Ag 2 S-NP in polymeric nanospheres greatly increases their NIR absorbance, resulting in enhanced optical imaging and photothermal heating effects. We therefore found that AgPCPP have potent contrast properties for PA and NIRF imaging, as well as for computed tomography (CT). We demonstrated the applicability of AgPCPP nanoparticles as a multimodal imaging probe that readily improves the conspicuity of breast tumors in vivo . PTT was performed using AgPCPP with NIR laser irradiation, which led to significant reduction in breast tumor growth and prolonged survival compared to free Ag 2 S-NP. Lastly, we observed a gradual decrease in AgPCPP retention in tissues over time with no signs of acute toxicity, thus providing strong evidence of safety and biodegradability. Therefore, AgPCPP may serve as a "one-for-all" theranostic agent that degrades into small components for excretion once the diagnostic and therapeutic tasks are fulfilled, thus providing good prospects for translation to clinical use.
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Ultrasmall silver sulfide nanoparticles (Ag 2 S-NP) have been identified as promising contrast agents for a number of modalities and in particular for dual-energy mammography. These Ag 2 S-NP have demonstrated marked advantages over clinically available agents with the ability to generate higher contrast with high biocompatibility. However, current synthesis methods are low-throughput and highly time-intensive, limiting the possibility of large animal studies or eventual clinical use of this potential imaging agent. We herein report the use of a scalable silicon microfluidic system (SSMS) for the large-scale synthesis of Ag 2 S-NP. Using SSMS chips with 1 channel, 10 parallelized channels, and 256 parallelized channels, we determined that the Ag 2 S-NP produced were of similar quality as measured by core size, concentration, UV-visible spectrometry, and in vitro contrast generation. Moreover, by combining parallelized chips with increasing reagent concentration, we were able to increase output by an overall factor of 3,400. We also found that in vivo imaging contrast generation was consistent across synthesis methods and confirmed renal clearance of the ultrasmall nanoparticles. Finally, we found best-in-class clearance of the Ag 2 S-NP occurred within 24 hours. These studies have identified a promising method for the large-scale production of Ag 2 S-NP, paving the way for eventual clinical translation.
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Medical imaging, which empowers the detection of physiological and pathological processes within living subjects, has a vital role in both preclinical and clinical diagnostics. Contrast agents are often needed to accompany anatomical data with functional information or to provide phenotyping of the disease in question. Many newly emerging contrast agents are based on nanomaterials as their high payloads, unique physicochemical properties, improved sensitivity and multimodality capacity are highly desired for many advanced forms of bioimaging techniques and applications. Here, we review the developments in the field of nanomaterial-based contrast agents. We outline important nanomaterial design considerations and discuss the effect on their physicochemical attributes, contrast properties and biological behaviour. We also describe commonly used approaches for formulating, functionalizing and characterizing these nanomaterials. Key applications are highlighted by categorizing nanomaterials on the basis of their X-ray, magnetic, nuclear, optical and/or photoacoustic contrast properties. Finally, we offer our perspectives on current challenges and emerging research topics as well as expectations for future advancements in the field.
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The therapeutic efficacy of photodynamic therapy is limited by the ability of light to penetrate tissues. Due to this limitation, Cerenkov luminescence (CL) from radionuclides has recently been proposed as an alternative light source in a strategy referred to as Cerenkov radiation induced therapy (CRIT). Semiconducting polymer nanoparticles (SPNs) have ideal optical properties, such as large absorption cross-sections and broad absorbance, which can be utilized to harness the relatively weak CL produced by radionuclides. SPNs can be doped with photosensitizers and have nearly 100% energy transfer efficiency by multiple energy transfer mechanisms. Herein, we investigated an optimized photosensitizer doped SPN as a nanosystem to harness and amplify CL for cancer theranostics. We found that semiconducting polymers significantly amplified CL energy transfer efficiency. Bimodal PET and optical imaging studies showed high tumor uptake and retention of the optimized SPNs when administered intravenously or intratumorally. Lastly, we found that photosensitizer doped SPNs have excellent potential as a cancer theranostics nanosystem in an in vivo tumor therapy study. Our study shows that SPNs are ideally suited to harness and amplify CL for cancer theranostics, which may provide a significant advancement for CRIT that are unabated by tissue penetration limits.
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OBJECTIVE: To analyze the impact of Body Mass Index (BMI) on clinical and patient-reported outcomes following gender-affirming mastectomy (GM). BACKGROUND: BMI is a barrier for obese patients seeking GM despite increasing evidence that it is safe in this population. Currently little is known about the impact of BMI on chest-specific body image and satisfaction following GM. METHODS: This single-center, cross-sectional study included individuals 18 years and older who underwent GM between 1990-2020 and were at least 2 years post-operative. Patient-reported chest-specific body image was measured using the BODY-Q and Gender Congruence and Life Satisfaction (GCLS) chest subscales. Satisfaction was measured using the Holmes-Rovner Satisfaction with Decision (SWD) scale. Clinical and demographic variables were identified from chart review. Bivariate analysis was performed to determine if BMI was associated with chest-specific body image, satisfaction, complications within 30 days or revisions in GM. RESULTS: Two hundred twenty-seven individuals meeting eligibility criteria were contacted to participate and one hundred thirty-seven responded (60.4% response rate). The mean age was 29.1 (SD=9.0) and mean BMI was 30.9 (SD=8.0), with 26.4% (N=60) of the cohort having a BMI>35. Chest-specific body image, and satisfaction with decision did not vary by BMI or breast resection weight. Complications and revisions were not associated with BMI. CONCLUSION: Individuals undergoing GM reported high rates of satisfaction following GM regardless of BMI. Complication and revision rates did not vary significantly by BMI or breast resection weight. Surgeons should re-evaluate the role BMI plays in patient selection and counseling for GM.
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Dual-energy computed tomography (DECT) is a commonly used imaging technique for detecting and diagnosing liver cancer. Currently, it is performed using clinically approved iodinated small molecule contrast agents (CAs). However, these iodinated CAs have several drawbacks, including sub-optimal contrast generation and contra-indication in patients with renal insufficiency. Herein, we synthesized tungsten-based CAs (i.e., WO3-x NPs) with excellent biocompatibility and investigated their effectiveness in DECT imaging. WO3-x NPs significantly enhanced the contrast between liver tumors and normal liver tissues as indicated by in vivo DECT imaging. Furthermore, WO3-x NPs exhibited excellent biocompatibility and minimal systemic toxicity. This study introduces a novel class of CAs for DECT and presents a promising method for accurate early diagnosis of liver tumors.
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Neoplasias Hepáticas , Nanopartículas , Humanos , Meios de Contraste , Tungstênio , Compostos Radiofarmacêuticos , Tomografia Computadorizada por Raios X/métodos , Neoplasias Hepáticas/diagnóstico por imagemRESUMO
Dental caries is the most common human disease caused by oral biofilms despite the widespread use of fluoride as the primary anticaries agent. Recently, an FDA-approved iron oxide nanoparticle (ferumoxytol, Fer) has shown to kill and degrade caries-causing biofilms through catalytic activation of hydrogen peroxide. However, Fer cannot interfere with enamel acid demineralization. Here, we show notable synergy when Fer is combined with stannous fluoride (SnF2), markedly inhibiting both biofilm accumulation and enamel damage more effectively than either alone. Unexpectedly, we discover that the stability of SnF2 is enhanced when mixed with Fer in aqueous solutions while increasing catalytic activity of Fer without any additives. Notably, Fer in combination with SnF2 is exceptionally effective in controlling dental caries in vivo, even at four times lower concentrations, without adverse effects on host tissues or oral microbiome. Our results reveal a potent therapeutic synergism using approved agents while providing facile SnF2 stabilization, to prevent a widespread oral disease with reduced fluoride exposure.
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Cárie Dentária , Fluoretos de Estanho , Humanos , Fluoretos de Estanho/farmacologia , Fluoretos de Estanho/uso terapêutico , Fluoretos/farmacologia , Cárie Dentária/prevenção & controle , Biofilmes , Fluoreto de Sódio/farmacologiaRESUMO
Importance: There has been increasing legislative interest in regulating gender-affirming surgery, in part due to the concern about decisional regret. The regret rate following gender-affirming surgery is thought to be approximately 1%; however, previous studies relied heavily on ad hoc instruments. Objective: To evaluate long-term decisional regret and satisfaction with decision using validated instruments following gender-affirming mastectomy. Design, Setting, and Participants: For this cross-sectional study, a survey of patient-reported outcomes was sent between February 1 and July 31, 2022, to patients who had undergone gender-affirming mastectomy at a US tertiary referral center between January 1, 1990, and February 29, 2020. Exposure: Decisional regret and satisfaction with decision to undergo gender-affirming mastectomy. Main Outcomes and Measures: Long-term patient-reported outcomes, including the Holmes-Rovner Satisfaction With Decision scale, the Decision Regret Scale, and demographic characteristics, were collected. Additional information was collected via medical record review. Descriptive statistics and univariable analysis using Fisher exact and Wilcoxon rank sum tests were performed to compare responders and nonresponders. Results: A total of 235 patients were deemed eligible for the study, and 139 responded (59.1% response rate). Median age at the time of surgery was 27.1 (IQR, 23.0-33.4) years for responders and 26.4 (IQR, 23.1-32.7) years for nonresponders. Nonresponders (n = 96) had a longer postoperative follow-up period than responders (median follow-up, 4.6 [IQR, 3.1-8.6] vs 3.6 [IQR, 2.7-5.3] years, respectively; P = .002). Nonresponders vs responders also had lower rates of depression (42 [44%] vs 94 [68%]; P < .001) and anxiety (42 [44%] vs 97 [70%]; P < .001). No responders or nonresponders requested or underwent a reversal procedure. The median Satisfaction With Decision Scale score was 5.0 (IQR, 5.0-5.0) on a 5-point scale, with higher scores noting higher satisfaction. The median Decision Regret Scale score was 0.0 (IQR, 0.0-0.0) on a 100-point scale, with lower scores noting lower levels of regret. A univariable regression analysis could not be performed to identify characteristics associated with low satisfaction with decision or high decisional regret due to the lack of variation in these responses. Conclusions and Relevance: In this cross-sectional survey study, the results of validated survey instruments indicated low rates of decisional regret and high levels of satisfaction with decision following gender-affirming mastectomy. The lack of dissatisfaction and regret impeded the ability to perform a more complex statistical analysis, highlighting the need for condition-specific instruments to assess decisional regret and satisfaction with decision following gender-affirming surgery.
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Neoplasias da Mama , Mastectomia , Humanos , Feminino , Estudos Transversais , Tomada de Decisões , Neoplasias da Mama/cirurgia , Satisfação do Paciente , EmoçõesRESUMO
Biofilms are structured communities of microbial cells embedded in a self-produced matrix of extracellular polymeric substances. Biofilms are associated with many health issues in humans, including chronic wound infections and tooth decay. Current antimicrobials are often incapable of disrupting the polymeric biofilm matrix and reaching the bacteria within. Alternative approaches are needed. Here, we described a complex structure of a dextran-coated gold-in-gold cage nanoparticle that enabled photoacoustic and photothermal properties for biofilm detection and treatment. Activation of these nanoparticles with a near infrared laser could selectively detect and kill biofilm bacteria with precise spatial control and in a short timeframe. We observed a strong biocidal effect against both Streptococcus mutans and Staphylococcus aureus biofilms in mouse models of oral plaque and wound infections, respectively. These effects were over 100 times greater than those seen with chlorhexidine, a conventional antimicrobial agent. Moreover, this approach did not adversely affect surrounding tissues. We concluded that photothermal ablation using theranostic nanoparticles is a rapid, precise, and nontoxic method to detect and treat biofilm-associated infections.
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Nanopartículas , Técnicas Fotoacústicas , Infecção dos Ferimentos , Animais , Camundongos , Antibacterianos , Biofilmes , Ouro/farmacologia , Ouro/química , Nanopartículas/química , Medicina de PrecisãoRESUMO
Ewing sarcoma (ES), which is characterized by the presence of oncogenic fusion proteins such as EWS/FLI1, is an aggressive pediatric malignancy with a high rate of early dissemination and poor outcome after distant spread. Here we demonstrate that the SIX1 homeoprotein, which enhances metastasis in most tumor types, suppresses ES metastasis by co-regulating EWS/FLI1 target genes. Like EWS/FLI1, SIX1 promotes cell growth/transformation, yet dramatically inhibits migration and invasion, as well as metastasis in vivo. We show that EWS/FLI1 promotes SIX1 protein expression, and that the two proteins share genome-wide binding profiles and transcriptional regulatory targets, including many metastasis-associated genes such as integrins, which they co-regulate. We further show that SIX1 downregulation of integrins is critical to its ability to inhibit invasion, a key characteristic of metastatic cells. These data demonstrate an unexpected anti-metastatic function for SIX1, through coordinate gene regulation with the key oncoprotein in ES, EWS/FLI1.