ABSTRACT
BACKGROUND: An array of evidence shows how the presence of implicit bias in clinical encounters can negatively impact provider-patient communication, quality of care and ultimately contribute to health inequities. Reflexive practice has been explored as an approach to identify and address implicit bias in healthcare providers, including medical students. At the Lausanne School of Medicine, a clinically integrated module was introduced in 2019 to raise students' awareness of gender bias in medical practice using a reflexivity and positionality approach. The purpose of this study is to describe the gender bias that were identified by medical students, analysing their types, places and modes of emergence during a clinical encounter. It further explores how positionality supported students' reflection on the way in which social position modulates their relationship to patients. METHODS: As part of the teaching activity, medical students individually reflected on gender bias in a specific clinical encounter by answering questions in their electronic portfolio. The questionnaire included a section on positionality. We qualitatively analysed the students' assignments (n=76), applying a thematic analysis framework. RESULTS: Medical students identified and described gender biases occurring at different moments of the clinical encounter (anamnesis (i.e. patient history), physical exam, differential diagnosis, final management). They causally associated these biases with wider social phenomena such as the gendered division of labour or stereotypes around sexuality and gender. Analysing students' reflections on how their position influenced their relationship with patients, we found that the suggested exercise revealed a major contradiction in the process of medical enculturation: the injunction to be neutral and objective erases the social and cultural context of patients and impedes an understanding of gender bias. CONCLUSION: Gender biases are present in the different steps of a clinical consultation and are rooted in broader gendered social representations. We further conclude that the tension between a quest for objectivity and the reality of social encounters should be made explicit to students, because it is constitutive of medical practice.
Subject(s)
Sexism , Students, Medical , Humans , Sexism/psychology , Students, Medical/psychology , Students, Medical/statistics & numerical data , Male , Female , Switzerland , Surveys and Questionnaires , Physician-Patient Relations , Universities , Adult , CommunicationABSTRACT
Health data show that there are differences in clinical management based on gender. One hypothesis is that these differences in management are not intentional discrimination but are the result of implicit and unconscious biases on the part of healthcare providers. These biases influence the clinical reasoning and practice of providers. This article, using clinical examples, illustrates how reflective practice is integrated into medical teaching in Lausanne to enable students to identify their biases, control them and ensure fair and relevant care. Students are also prompted to reflect on their social positionality, as thematising the power dynamics around knowledge and social interactions helps to better understand and prepare for medical practice.
Les données en santé font état de différences de traitement médical en fonction du genre. L'une des hypothèses est que ces différences de traitement ne sont pas des discriminations intentionnelles, mais relèvent de biais implicites et inconscients des soignant-e-s. Ces biais ont une influence sur les raisonnements et la pratique clinique des soignant-e-s. Cet article, à l'aide d'exemples cliniques, illustre comment la pratique réflexive est intégrée à l'enseignement en médecine à Lausanne afin de permettre aux étudiant-e-s d'identifier leurs biais, de les contrôler et d'assurer des soins équitables et pertinents. Il est également proposé aux étudiant-e-s de réfléchir à leur positionnement social, car thématiser les dynamiques de pouvoir autour des savoirs et des interactions sociales permet de mieux comprendre et préparer la pratique médicale.
Subject(s)
Sexism , Humans , Sexism/psychology , Female , Male , Students, Medical/psychology , Education, Medical/methodsABSTRACT
Imaging in the shortwave infrared (SWIR, 1000-1700 nm) region is gaining traction for biomedical applications, leading to an in-depth search for fluorophores emitting at these wavelengths. The development of SWIR emitters, to be used in vivo in biological media, is mostly hampered by the considerable lipophilicity of the structures, resulting from the highly conjugated scaffold required to shift the emission to this region, that limit their aqueous solubility. In this work, we have modulated a known SWIR emitter, named Flav7, by adding hydrophilic moieties to the flavylium scaffold and we developed a new series of Flav7-derivatives, which proved to be indeed more polar than the parent compound, but still not freely water-soluble. Optical characterization of these derivatives allowed us to select FlavMorpho, a new compound with improved emission properties compared to Flav7. Encapsulation of the two compounds in micelles resulted in water-soluble SWIR emitters, with FlavMorpho micelles being twice as emissive as Flav7 micelles. The SWIR emission extent of FlavMorpho micelles proved also superior to the tail-emission of Indocyanine Green (ICG), the FDA-approved reference cyanine, in the same region, by exciting the probes at their respective absorption maxima in phosphate buffered saline (PBS) solution. The availability of optical imaging devices equipped with lasers able to excite these dyes at their maximum of absorption in the SWIR region, could pave the way for implemented SWIR imaging results.
Subject(s)
Drug Design , Fluorescent Dyes , Fluorescent Dyes/chemistry , Fluorescent Dyes/chemical synthesis , Molecular Structure , Infrared Rays , Micelles , Optical Imaging , SolubilityABSTRACT
Commercially available near-infrared (NIR) dyes, including indocyanine green (ICG), display an end-tail of the fluorescence emission spectrum detectable in the short-wave infrared (SWIR) window. Imaging methods based on the second NIR spectral region (1,000-1,700â nm) are gaining interest within the biomedical imaging community due to minimal autofluorescence and scattering, allowing higher spatial resolution and depth sensitivity. Using a SWIR fluorescence imaging device, the properties of ICG vs. heptamethine cyanine dyes with emission >800â nm were evaluated using tissue-simulating phantoms and animal experiments. In this study, we tested the hypothesis that an increased rigidity of the heptamethine chain may increase the SWIR imaging performance due to the bathochromic shift of the emission spectrum. Fluorescence SWIR imaging of capillary plastic tubes filled with dyes was followed by experiments on healthy animals in which a time series of fluorescence hindlimb images were analyzed. Our findings suggest that higher spatial resolution can be achieved even at greater depths (>5â mm) or longer wavelengths (>1,100â nm), in both tissue phantoms and animals, opening the possibility to translate the SWIR prototype toward clinical application.
ABSTRACT
BACKGROUND: Human Cytomegalovirus (HCMV) is still one of the major concerning infection in hematopoietic stem cell transplant (HSCT) recipients. Letermovir (LTV) has been recently introduced for HCMV prophylaxis in adult patients who received allogeneic HSCT. However, many aspects related to immune reconstitution need to be further explored. The aim of this study was to define the prognostic role of HCMV-specific T-cell frequency measured at the end of LTV prophylaxis in predicting the risk for clinically significant HCMV infection (i.e. infection requiring antiviral treatment) after the stop of the prophylaxis. METHODS: Sixty-six adult patients who underwent allogeneic HSCT were enrolled and HCMV DNAemia was prospectively monitored. Additionally, HCMV-specific T-cell response was evaluated using ELISpot assay against two different antigens (HCMV infected cell lysate and pp65 peptide pool). RESULTS: Ten patients (15.2%) developed at least one positive HCMV DNAemia episode during LTV prophylaxis, whereas 50/66 (75.8%) patients developed at least one positive HCMV DNA event after LTV prophylaxis. Of note, 25 of them (50%) experienced a clinically significant HCMV infection. The median HCMV-specific T-cell response measured against HCMV lysate but not against pp65 peptide pool was lower in patients who developed HCMV clinically significant infection after prophylaxis. A ROC analysis revealed that the level of 0.04 HCMV-specific T cells/µl should be used as cut-off for development of clinically significant HCMV reactivation after prophylaxis. CONCLUSION: Assessment of HCMV-specific immunity upon discontinuation of universal prophylaxis with LTV should be considered as a method for identification of patients at risk for clinically significant HCMV infection.
Subject(s)
Cytomegalovirus Infections , Hematopoietic Stem Cell Transplantation , Adult , Humans , Cytomegalovirus/genetics , T-Lymphocytes , Antiviral Agents/therapeutic use , Hematopoietic Stem Cell Transplantation/adverse effects , Transplant Recipients , PeptidesABSTRACT
Monkeypox virus (MPXV) is a zoonotic disease endemic in the rainforest countries of Central and West Africa. Understanding the immune response in zoonosis is fundamental to prevent and contrast viral spreading. MPXV is a close relative of Variola (smallpox) virus and vaccination with vaccinia virus gives approximatively 85% of protection against MPXV. With the emergence of the recent MPXV outbreak, JYNNEOS vaccine has been proposed to individuals at high-risk of exposure. Comparative data on MPXV immune response in vaccinated or infected subjects are still limited. Here we set-up an immunofluorescence method for the evaluation of humoral response elicited by natural infection and healthy vaccinated subjects, including historically smallpox-vaccinated individuals and newly vaccinated subjects. Neutralization assay was also included, and in vaccinated subjects, cell-mediated response was evaluated. We observed that the natural infection produces a strong immune response that can control the disease. In naïve subjects, a second dose boosts the serological response to levels similar to those of the MPXV patients. Last, smallpox-vaccinated controls retain a degree of protection, even after years from vaccination, most visible in the t-cellular response.
Subject(s)
Mpox (monkeypox) , Smallpox , Humans , Monkeypox virus , Smallpox/prevention & control , Mpox (monkeypox)/epidemiology , Mpox (monkeypox)/prevention & control , Vaccinia virus , ImmunityABSTRACT
This article reviews how the distinction between the notions of gender, sex and sexualities has gradually evolved over the course of medical history. The definition of these concepts emerged in the context of the development of medical nosography to create categories that would distinguish the normal from the pathological. In the same way as somatic disorders, sexual behaviors are categorized and those that deviate from the norm and from the morality at that time, are taken care of by medicine.
Cet article vise à illustrer de quelle manière la distinction des notions de genre, de sexe et de sexualités a progressivement évolué au cours de l'histoire de la médecine. La définition de ces concepts est apparue dans un contexte de développement de la nosographie médicale pour créer des catégories permettant de distinguer le normal du pathologique. Parallèlement aux troubles somatiques, les comportements sexuels sont catégorisés, et ceux qui dévient, selon le contexte de la norme et de la morale, sont ainsi pris en charge par la médecine.
Subject(s)
Medicine , Sexual Behavior , Humans , Sexuality , Gender Identity , MoralsABSTRACT
The role and durability of the immunogenicity of the BNT162b2 mRNA vaccine against severe acute respiratory virus 2 (SARS-CoV-2), in cancer patients one year after receiving the third dose have to be elucidated. We have prospectively evaluated the long-term immunogenicity of the third dose of the SARS-CoV-2 BNT162b2 mRNA vaccine in 55 patients undergoing active treatment. Neutralizing antibody (NT Ab) titers against Omicron variants and total anti-trimeric S IgG levels were measured one year after the third dose. Heparinized whole-blood samples were used for the assessment of the SARS-CoV-2 interferon-γ release assay (IGRA). Thirty-seven patients (67.3%) showed positive total anti-trimeric S IgG one year after the third dose. Looking at the T-cell response against the spike protein, the frequency of responder patients did not decrease significantly between six and twelve months after the third dose. Finally, less than 20% of cancer patients showed an undetectable NT Ab titer against BA.1 and BA.5 variants of concern (VOCs). Underlying therapies seem to not affect the magnitude or frequency of the immune response. Our work underlines the persistence of humoral and cellular immune responses against BNT162b2 in a cohort of cancer patients one year after receiving the third dose, regardless of the type of underlying therapy.
Subject(s)
COVID-19 , Neoplasms , Virus Diseases , Humans , BNT162 Vaccine , COVID-19 Vaccines , Follow-Up Studies , SARS-CoV-2 , COVID-19/prevention & control , Neoplasms/therapy , Antibodies, Neutralizing , Immunity , Immunoglobulin G , Antibodies, Viral , mRNA VaccinesABSTRACT
Human cytomegalovirus (HCMV) infection represents a major complication for solid organ transplant recipients. The aim of this study was to verify if the measurement of HCMV-specific T-cells could help to identify patients protected against HCMV disease cytokine flow cytometry using infected dendritic cells as stimulus (CFC-iDC, which discriminates between CD4+ and CD8+ T cells), and ELISPOT, using infected cell lysate (ELISPOT-iCL) or pp65 (ELISPOT-pp65) as stimulus, were adopted. Among the 47 kidney transplant recipients (KTR) enrolled, 29 had a self-resolving HCMV infection (Controllers) and 18 required antiviral treatment (Non-Controllers). HCMV-specific T-cell frequency at the peak of HCMV infection identified Controllers and Non-Controllers, although the diagnostic performance of CD8+ CFC-iDC (area under the curve [AUC] of the receiver-operator characteristic curve: 0.65) was lower than that of CD4+ CFC-iDC (AUC: 0.83), ELISPOT-iCL (AUC: 0.83) and ELISPOT-pp65 (AUC: 0.80). CFC-iDC detected a protective immune reconstitution significantly earlier (median time: 38 days) than ELISPOT-iCL and ELISPOT-pp65 (median time: 126 and 133 days, respectively). Time to protective immune reconstitution in Non-Controllers was significantly longer than in Controllers with the ELISPOT and the CD4+ CFC-iDC assays, but not with CD8+ CFC-iDC. The majority of patients did not require antiviral treatment after protective immune reconstitution, with the exception of five patients according to CFC-iDC assay, one patient according to ELISPOT-iCL assay and three patients according to ELISPOT-pp65 assay. Monitoring the HCMV-specific immunological reconstitution with is effective in discriminating KTR at risk of or protected from HCMV disease and the ELISPOT assays are suitable for implementation in the clinical setting.
Subject(s)
Cytomegalovirus Infections , Kidney Transplantation , Humans , Cytomegalovirus , Enzyme-Linked Immunospot Assay , CD8-Positive T-Lymphocytes , Antigens, Viral , Antiviral Agents/therapeutic use , CytokinesABSTRACT
We reported the long-term kinetics of immune response after vaccination and evaluated the immunogenicity after a third dose of mRNA vaccine in 86 healthcare workers. Humoral response was analyzed by measuring anti-spike IgG and SARS-CoV-2 NTAbs titer; cell-mediated response was measured as frequency of IFN-γ producing T-cells and cell proliferation. Memory B cells secreting SARS-CoV-2 RBD-IgG were measured by B-spot assay. At three weeks after the third dose (T4), the frequency of subjects showing NT-Abs titer at the upper detection limit (≥640) was significantly higher than that observed at three weeks after the second dose (26/77; 33.7% vs. 9/77; 11.6%; p = 0.0018). Additionally, at T4, all the subjects reached positive levels of T-cell mediated response (median 110 SFU/106 PBMC, IQR 73-231). While the number of IFNγ-producing T-cells decreased between second and third dose administration, the T-cell proliferative response did not decrease but was sustained during the follow-up. Among T-cell subsets, a higher proliferative response was observed in CD4+ than in CD8+ population. Moreover, even if a decline in antibody response was observed between the second and third dose, a sustained persistence of memory B cells was observed. Subsequently, the third dose did not affect the frequency of memory B cells, while it restored or increased the peak antibody levels detected after the second dose.
ABSTRACT
Since the identification of the new severe acute respiratory syndrome virus 2 (SARS-CoV-2), a huge effort in terms of diagnostic strategies has been deployed. To date, serological assays represent a valuable tool for the identification of recovered COVID-19 patients and for the monitoring of immune response elicited by vaccination. However, the role of T-cell response should be better clarified and simple and easy to perform assays should be routinely introduced. The main aim of this study was to compare a home-made assay for whole blood stimulation with a standardized ELISpot assay design in our laboratory for the assessment of spike-specific T-cell response in vaccinated subjects. Even if a good correlation between the assays was reported, a higher percentage of responder subjects was reported for immunocompromised subjects with ELISpot assay (56%) than home-made whole blood stimulation assay (33%). Additionally, three commercial assays were compared with our home-made assay, reporting a good agreement in terms of both positive and negative results.
ABSTRACT
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has severely impacted on public health, mainly on immunosuppressed patients, including solid organ transplant recipients. Vaccination represents a valuable tool for the prevention of severe SARS-CoV-2 infection, and the immunogenicity of mRNA vaccines has been evaluated in transplanted patients. In this study, we investigated the role of a third dose of the BNT162b2 vaccine in a cohort of kidney transplant recipients, analyzing both humoral and cell-mediated responses. We observed an increased immune response after the third dose of the vaccine, especially in terms of Spike-specific T cell response. The level of seroconversion remained lower than 50% even after the administration of the third dose. Mycophenolate treatment, steroid administration and age seemed to be associated with a poor immune response. In our cohort, 11/45 patients experienced a SARS-CoV-2 infection after the third vaccine dose. HLA antibodies appearance was recorded in 7 out 45 (15.5%) patients, but none of the patients developed acute renal rejection. Further studies for the evaluation of long-term immune responses are still ongoing, and the impact of a fourth dose of the vaccine will be evaluated.
ABSTRACT
PURPOSE: This work aims to investigate the supramolecular binding interactions that occur between iodinated X-ray contrast agents (CAs) and macrocyclic gadolinium (Gd)-based MRI contrast agents (GBCAs). This study provides some new insights in the renal excretion pathways of the two types of imaging probes. METHODS: The water-proton relaxivities (r1 ) of clinically approved macrocyclic and linear GBCAs have been measured in the presence of different iodinated X-ray contrast agents at different magnetic field strengths in buffer and in serum. The in vivo MRI and X-ray CT of mice injected with either Gd-HPDO3A or a Gd-HPDO3A + iodixanol mixture were then acquired to assess the biodistribution of the two probes. RESULTS: A significant increase in r1 (up to approximately 200%) was observed for macrocyclic GBCAs when measured in the presence of an excess of iodinated X-ray CAs (1:100 mol:mol) in serum. The co-administration of Gd-HPDO3A and iodixanol in vivo resulted in a marked increase in the signal intensity of the kidney regions in T1 -weighted MR images. Moreover, the co-presence of the two agents resulted in the extended persistence of the MRI signal enhancement, suggesting that the Gd-HPDO3A/iodixanol adduct was eliminated more slowly than the typical washing out of Gd-HPDO3A. CONCLUSIONS: The reported results show that it is possible to detect the co-presence of iodinated agents and macrocyclic GBCAs in contrast-enhanced MR images. The new information may be useful in the design of novel experiments toward improved diagnostic outcomes.
Subject(s)
Contrast Media , Organometallic Compounds , Animals , Contrast Media/chemistry , Gadolinium , Heterocyclic Compounds , Magnetic Resonance Imaging/methods , Mice , Organometallic Compounds/metabolism , Renal Elimination , Tissue Distribution , Triiodobenzoic Acids , X-RaysABSTRACT
The immunogenicity of severe acute respiratory syndrome 2 virus (SARS-CoV-2) vaccines in immunocompromised patients remains to be further explored. Here, we evaluated the immunogenicity elicited by complete vaccination with BNT162b2 vaccine in solid organ transplant recipients (SOTRs). A cohort of 110 SOTRs from Northern Italy were vaccinated with two doses of BNT162b2 mRNA vaccine and prospectively monitored at baseline and after 42 days. Both SARS-CoV-2 naïve and recovered subjects were included. Humoral response elicited by vaccination, including SARS-CoV-2 neutralizing antibodies (SARS-CoV-2 NT Abs), was evaluated; additionally, ex-vivo ELISpot assay was performed for the quantification of Spike-specific T-cell response. Results were compared with those obtained in a cohort of healthy subjects. In a subset of patients, humoral and T-cell responses against delta variant were also evaluated. Less than 20% of transplanted subjects developed a positive humoral and cell-mediated response after complete vaccination schedule. Overall, median levels of immune response elicited by vaccination were significantly lower with respect to controls in SARS-CoV-2 naïve transplant, but not in SARS-CoV-2 recovered transplanted patients. Additionally, a significant impairment of both humoral and cell-mediated response was observed in mycophenolate-treated patients. Positive delta-SARS-CoV-2 NT Abs levels were detected in almost all the SARS-CoV-2 recovered subjects but not in previously uninfected patients. Our study supports previous observations of a low level of seroconversion after vaccination in transplanted patients.
ABSTRACT
D-Glucose and 3-O-Methyl-D-glucose (3OMG) have been shown to provide contrast in magnetic resonance imaging-chemical exchange saturation transfer (MRI-CEST) images. However, a systematic comparison between these two molecules has yet to be performed. The current study deals with the assessment of the effect of pH, saturation power level (B1 ) and magnetic field strength (B0 ) on the MRI-CEST contrast with the aim of comparing the in vivo CEST contrast detectability of these two agents in the glucoCEST procedure. Phosphate-buffered solutions of D-Glucose or 3OMG (20 mM) were prepared at different pH values and Z-spectra were acquired at several B1 levels at 37°C. In vivo glucoCEST images were obtained at 3 and 7 T over a period of 30 min after injection of D-Glucose or 3OMG (at doses of 1.5 or 3 g/kg) in a murine melanoma tumor model (n = 3-5 mice for each molecule, dose and B0 field). A markedly different pH dependence of CEST response was observed in vitro for D-Glucose and 3OMG. The glucoCEST contrast enhancement in the tumor region following intravenous administration (at the 3 g/kg dose) was comparable for both molecules: 1%-2% at 3 T and 2%-3% at 7 T. The percentage change in saturation transfer that resulted was almost constant for 3OMG over the 30-min period, whereas a significant increase was detected for D-Glucose. Our results show similar CEST contrast efficiency but different temporal kinetics for the metabolizable and the nonmetabolizable glucose derivatives in a tumor murine model when administered at the same doses.
Subject(s)
3-O-Methylglucose/chemistry , Glucose/chemistry , Magnetic Resonance Imaging/methods , Melanoma, Experimental/diagnostic imaging , Animals , Cell Line, Tumor , Hydrogen-Ion Concentration , Magnetic Fields , Male , Melanoma, Experimental/metabolism , Mice , Mice, Inbred C57BLABSTRACT
Labeling of macrophages with perfluorocarbon (PFC)-based compounds allows the visualization of inflammatory processes by 19F-magnetic resonance imaging (19F-MRI), due to the absence of endogenous background. Even if PFC-labeling of monocytes/macrophages has been largely investigated and used, information is lacking about the impact of these agents over the polarization towards one of their cell subsets and on the best way to image them. In the present work, a PFC-based nanoemulsion was developed to monitor the course of inflammation in a model of spinal cord injury (SCI), a pathology in which the understanding of immunological events is of utmost importance to select the optimal therapeutic strategies. The effects of PFC over macrophage polarization were studied in vitro, on cultured macrophages, and in vivo, in a mouse SCI model, by testing and comparing various cell tracking protocols, including single and multiple administrations, the use of MRI or Point Resolved Spectroscopy (PRESS), and application of pre-saturation of Kupffer cells. The blood half-life of nanoemulsion was also investigated by 19F Magnetic Resonance Spectroscopy (MRS). In vitro and in vivo results indicate the occurrence of a switch towards the M2 (anti-inflammatory) phenotype, suggesting a possible theranostic function of these nanoparticles. The comparative work presented here allows the reader to select the most appropriate protocol according to the research objectives (quantitative data acquisition, visual monitoring of macrophage recruitment, theranostic purpose, rapid MRI acquisition, etc.). Finally, the method developed here to determine the blood half-life of the PFC nanoemulsion can be extended to other fluorinated compounds.
ABSTRACT
Removal of ribonucleotides (rNMPs) incorporated into the genome by the ribonucleotide excision repair (RER) is essential to avoid genetic instability. In eukaryotes, the RNaseH2 is the only known enzyme able to incise 5' of the rNMP, starting the RER process, which is subsequently carried out by replicative DNA polymerases (Pols) δ or ϵ, together with Flap endonuclease 1 (Fen-1) and DNA ligase 1. Here, we show that the DEAD-box RNA helicase DDX3X has RNaseH2-like activity and can support fully reconstituted in vitro RER reactions, not only with Pol δ but also with the repair Pols ß and λ. Silencing of DDX3X causes accumulation of rNMPs in the cellular genome. These results support the existence of alternative RER pathways conferring high flexibility to human cells in responding to the threat posed by rNMPs incorporation.
Subject(s)
DEAD-box RNA Helicases/metabolism , Ribonucleotides/metabolism , Adenosine Triphosphate/metabolism , Catalytic Domain , Cell Line , DEAD-box RNA Helicases/chemistry , DNA Polymerase beta/metabolism , Humans , Protein Domains , RNA-Binding Motifs , Ribonuclease H/chemistry , Ribonuclease H/metabolismABSTRACT
PURPOSE: Prostate cancer (PCa), the most widespread male cancer in western countries, is generally eradicated by surgery, especially if localized. However, during surgical procedures, it is not always possible to identify malignant tissues by visual inspection. Among the possible consequences, there is the formation of positive surgical margins, often associated with recurrence. In this work, the gastrin-releasing peptide receptor (GRPR), overexpressed in the prostatic carcinoma and not in healthy tissues or in benign hyperplasia (BPH), is proposed as target molecule to design a novel near-infrared fluorescent (NIRF) probe for image-guided prostatectomy. PROCEDURES: The NIRF dye Sulfo-Cy5.5 was conjugated to a Bombesin-like peptide (BBN), targeting GRPR. The final product, called BBN-Cy5.5, was characterized and tested in vitro on PC-3, DU145, and LnCAP cell lines, using unconjugated Sulfo-Cy5.5 as control. In vivo biodistribution studies were performed by optical imaging in PC-3 tumor-bearing and healthy mice. Finally, simulation of the surgical protocol was carried out. RESULTS: BBN-Cy5.5 showed high water solubility and a good relative quantum yield. The ability of the probe to recognize the GRPR, highly expressed in PC-3 cells, was tested both in vitro and in vivo, where a significant tumor accumulation was achieved 24 h post-injection. Furthermore, a distinguishable fluorescent signal was visible in mice bearing PCa, when the surgery was simulated. By contrast, low signal was found in healthy or BPH-affected mice. CONCLUSIONS: This work proposes a new NIRF probe ideal to target GRPR, biomarker of PCa. The promising data obtained suggest that the dye could allow the real-time intraoperative visualization of prostate cancer.
Subject(s)
Bombesin/chemistry , Fluorescent Dyes/pharmacokinetics , Optical Imaging/methods , Prostatic Neoplasms/surgery , Receptors, Bombesin/metabolism , Surgery, Computer-Assisted/methods , Animals , Cell Line, Tumor , Fluorescent Dyes/chemistry , Humans , Male , Mice , Mice, Nude , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology , Spectroscopy, Near-Infrared , Tissue Distribution , Xenograft Model Antitumor AssaysABSTRACT
Cancer cells are characterized by a metabolic shift in cellular energy production, orchestrated by the transcription factor HIF-1α, from mitochondrial oxidative phosphorylation to increased glycolysis, regardless of oxygen availability (Warburg effect). The constitutive upregulation of glycolysis leads to an overproduction of acidic metabolic products, resulting in enhanced acidification of the extracellular pH (pHe ~ 6.5), which is a salient feature of the tumor microenvironment. Despite the importance of pH and tumor acidosis, there is currently no established clinical tool available to image the spatial distribution of tumor pHe. The purpose of this review is to describe various imaging modalities for measuring intracellular and extracellular tumor pH. For each technique, we will discuss main advantages and limitations, pH accuracy and sensitivity of the applied pH-responsive probes and potential translatability to the clinic. Particular attention is devoted to methods that can provide pH measurements at high spatial resolution useful to address the task of tumor heterogeneity and to studies that explored tumor pH imaging for assessing treatment response to anticancer therapies.
Subject(s)
Acidosis/diagnostic imaging , Acidosis/metabolism , Neoplasms/diagnostic imaging , Neoplasms/metabolism , Acidosis/pathology , Animals , Humans , Hydrogen-Ion Concentration , Magnetic Resonance Spectroscopy/methods , Neoplasms/pathologyABSTRACT
PURPOSE: The discussed topic about gadolinium-based contrast agents (GBCA) safety has recently been revived due to the evidence of hyperintensities observed in the dentate nucleus (DN) and globus pallidus (GP) in the brain of patients with normal kidney function. Several preclinical studies have been conducted to understanding how the use of GBCAs can promote the gadolinium deposition in the brain. Here, we evaluate the impact of chronic cerebral hypoperfusion on gadolinium presence. METHODS: T1 hyperintensities and BBB integrity were evaluated by MRI in chronically hypoperfused and healthy rats injected with either gadodiamide or hypertonic saline. Additionally, the assessment of glucose metabolism by PET imaging and the gadolinium content by ICP-MS was performed after the last MR scan. RESULTS: Chronically hypoperfused rats displayed a greater MRI T1w signal in the DCN and hippocampus compared to Sham-operated animals, suggesting gadolinium accumulation. Dynamic contrast-enhanced (DCE) MRI assessment of BBB permeability revealed loss of integrity (high Ktrans) after rat injury in the dentate nuclei and hippocampus. Ex vivo tissue analysis showed greater gadolinium retention in the cerebellum and subcortical regions, supporting the imaging finding. FDG-PET imaging of the cerebellum did not reveal abnormal uptake in the DCN after chronic cerebral hypoperfusion. CONCLUSION: Higher signal intensity followed by higher Gd concentration observed in DCN and hippocampus of animals subjected to cerebral injury can be associated with an increase in BBB permeability due to the applied vascular dementia animal model. Nonetheless, no glucose metabolism abnormalities were detected in chronically hypoperfused cerebellum.