Design, synthesis and application of luminescent rhenium complexes in cell imaging

This thesis describes the development of a new variety of lumophores, in particular luminescent rhenium(I) complexes of the type Re(bisim)(CO)3L n+, where bisim represents a bisimine derivative, e.g. bipyridine, and Lisa pyridine derivative (n = 1) or a chloride (n = 0), suitable for specific cell imaging and whose modified photophysical properties overcome some of the problems associated with traditional imaging agents (small Stokes shift, short lifetimes, etc). Specifically the successful synthesis and photophysical studies of a chemical model to validate the concept of a membrane permeable cell-imaging device, fac-Re0)ipyXCO)3(PyCH2COO(CH2)3OTBD) +, are presented. Further investigations towards and improved cell imaging agent, considering different issues like water solubility, lipophilicity and cell encapsulation rate, are then undertaken. Consequently, a new range of water soluble rhenium complexes, ykc- Re(bisimXCO)3(L) n" where bisim is a water soluble bathophenanthroline and L is a pyridine derivative (n = 2) or a chloride (n = 1), as well as a variety of novel yac-Re(bisimXCO)3Cl complexes, where bisim is a terpyridine derivative bearing a self destruction device which can be triggered by nitroreductase, are also presented. Additionally, the synthesis and structural description of a trinuclear rhenium complex is reported, along with a discussion of its use in inclusion experiments and attempts at analogue formation. The design and synthesis of a thiol selective luminescent rhenium complex, fac-Re(bipyXCO)3(PyCH2Cl) +, is described, along with the demonstration of its thiol selectivity both in vitro and in vivo as demonstrated by specific mitochondrial localization. Finally, studies of membrane permeability in liposome models, cellular uptake and localization in different cells such as Spironucleous vortens, yeast cells and human breast cancer cells of a variety of rhenium complexes above cited are also reported. These results combine to demonstrate the promising future of this new class of imaging probes as specific cell imaging agents and therefore, this work represents the initial step in the growing area of the development of transition metal based imaging agents

Synthesis and antiproliferative study of phosphorescent multimetallic Re(I)/Au(I) complexes containing fused imidazo[4, 5-f]-1, 10-phenanthroline core

Five heterobimetallic Re-I/Au-I and a tri-metallic Re-I/Au-I/Re-I species following the formulas fac-ReCl (CO)(3)(NNCAuR)](0/+) and (fac-ReCl (CO)(3)(NNC)])(2)Au](+), where R is an iodide (1), phenylacetylene (2), dodecanethiol (3), 2, 3, 4, 6-tetra-O-acetyl-1-thio-beta-D-glucopyranose (4) and JohnPhos (5) and NNC is the fused imidazo4, 5-f]-1, 10-phenanthroline heterotopic ligand, were synthesised and fully characterised by a variety of spectroscopic and analytical techniques. The resultant complexes are luminescent in the orange region, revealing classical metal-to-ligand charge transfer ((MLCT)-M-3) ((Re (d pi) -> (NNC)(pi*)) emission in aerated DMSO solution. The red shifted emission observed on going from 3 to 4 suggests that the electronic properties of the gold ancillary ligand are implicated in the emissive properties. Antiproliferative activity in tumour cell lines, lung (A549) and cervix (HeLa) cells revealed that only complex 4 containing a 2, 3, 4, 6-tetra-O-acetyl-1-thio-beta-D-glucopyranose as gold ancillary ligand possesses certain cytotoxicity in both cell lines

Compuestos luminiscentes de Re(I) con aplicaciones en bioimagen

Este trabajo describe el diseño y la síntesis de una nueva familia de complejos luminiscentes de renio (I) del tipo fac-[Re(NN)(CO)3L]n+, donde NN representa un derivado de fenantrolina y L es, o bien un derivado de piridina o acetonitrilo (n=1), o bien un cloruro o triflato (n=0), con potencial aplicación en imagen celular y cuyas propiedades fotofísicas superan algunos de los problemas asociados con los agentes tradicionales de imagen. En concreto, se presentan la síntesis y los estudios fotofísicos de una serie de especies neutras de Re(I) como son el fac-[Re(2,9(Me)2-Phen)(CO)3Cl], fac-[Re(2,9(CHO)2-Phen)(CO)3Cl] y fac-[Re(2, 9(CH2OH)2-Phen)(CO)3Cl]. Además, se describe la activación de estas especies por abstracción o reacción de sustitución del haluro por un ligando más lábil. Por último, también se describe la síntesis de complejo fac-[Re(2,9(Me)2-Phen)(CO)3(3-CH2OH-Py)]+, que se logró mediante la sustitución del ligando activado (OTf) en el compuesto fac-[Re(2,9(Me)2-Phen)(CO)3(OTf)] por 3-hidroximetil-piridina. Además de su caracterización completa, se analizó su estructura cristalina por difracción de rayos X. Por otra parte, se recoge también el intento de transformar esta especie en su análogo fac-[Re(2,9(Me)2-Phen)(CO)3(3-CH2Cl-Py)]+, la cual debería de ser un complejo con afinidad a reaccionar con tiolatos. Igualmente se describen los intentos de las síntesis de fac-[Re(2,9(CHO)2-Phen)(CO)3(3-CH2OH-Py)]+ y fac-[Re(2,9(CH2OH)2-Phen)(CO)3(3-CH2Cl-Py)]+. Se realizaron los estudios fotofísicos de las especies fac-[Re(2,9(Me)2-Phen)(CO)3Cl], fac-[Re(2,9(CHO)2-Phen)(CO)3Cl], fac-[Re (2,9(CH2OH)2-Phen)(CO)3Cl] y fac-[Re(2,9(Me)2-Phen)(CO)3(3-CH2OH-Py)]+ por espectroscopía de fluorescencia y visible-UV. Finalmente, se analizó la citotoxicidad de fac-[Re(2,9(Me)2-Phen)(CO)3(3-CH2OH-Py)]+ en células humanas de adenocarcinoma de cáncer de cérvix, células HeLa, así como su interacción con el ADN. Además de estos estudios, también se utilizó la microscopía fluorescencia para validar éste compuesto como un potencial agente de contraste. Estos resultados demuestran el futuro prometedor de esta nueva clase de compuestos como agentes de imagen y, por lo tanto, este trabajo representa un paso adelante en la creciente área del desarrollo de agentes de imagen basados en metales de transición

Compuestos metálicos para bioimagen y terapia

En este trabajo se ha realizado la síntesis de dos familias de ligandos tioureas del tipo RNHCSNHR’, donde R representa un grupo fluoreno o acridina y R’ es un fenilo, bencilo o 3-fluorofenilo, así como su posterior coordinación a Ag (I) cuando ha sido posible. Además, se han estudiado sus propiedades fotofísicas, citotóxicas y su posible aplicación en microscopía de fluorescencia. Específicamente, se ha realizado la síntesis y caracterización de cada uno de los ligandos mediante técnicas de espectroscopia infrarroja, de resonancia magnética nuclear de protón, carbono y flúor, COSY, APT, HSQC, HMBC, y así hacer una comparación exhaustiva con los complejos metálicos sintetizados posteriormente. Se han llevado a cabo diferentes reacciones de coordinación de los ligandos derivados de fluoreno con AgOTf en diferentes estequiometrias L:Ag (1:1 y 2:1). En estos derivados, los ligandos objeto de estudio se coordinan al centro metálico a través del átomo de azufre de la tiourea. Posteriormente, se ha procedido a la caracterización estructural de los nuevos complejos sintetizados mediante las técnicas habituales nombradas anteriormente. La comparación de los espectros de los nuevos complejos y los ligandos de partida ha servido para confirmar que la coordinación del metal se ha producido satisfactoriamente. Así mismo se ha intentado las reacciones de coordinación de los ligandos derivados de acridina con AgPPh3OTf. Lamentablemente, estos complejos no han podido ser aislados para su posterior caracterización. A continuación se ha elaborado un estudio de las propiedades fotofísicas utilizando las técnicas de UV-visible y espectroscopia de emisión así como un estudio de la actividad citotóxica de los diferentes ligandos y sus correspondientes complejos metálicos mediante el método MTT en la línea celular A-549 de cáncer de pulmón. Finalmente se ha realizado un experimento de microscopía de fluorescencia con una tiourea de cada familia para poder elucidar su comportamiento a nivel celular

Complejos metálicos luminiscentes con aplicaciones en terapia y bioimagen

Con la vista puesta en el desarrollo de especies químicas útiles en medicina diagnóstica y terapéutica se ha tratado de sintetizar una serie de compuestos de coordinación tanto monometálicos como heterobimetálicos del tipo fac-[Re(bipy)(CO)3L]+ y fac-[Re(bipy)(CO)3(L-AuPPh3)]+ respectivamente, donde L representa a distintos derivados de mercaptopiridina que actuarán como ligandos conectores entre los fragmentos metálicos de renio y oro. En ellos, el de renio aporta las propiedades luminiscentes, mientras que el de oro proporciona efectos antiproliferativos. Los compuestos obtenidos se han caracterizado debidamente mediante técnicas de espectroscopia de RMN e IR, espectrometría de masas y, cuando ha sido posible, por difracción de rayos X. Además, se han estudiado sus propiedades fotofísicas con objeto de valorar su viabilidad como agentes de imagen en microscopía de fluorescencia, técnica cuyo carácter no invasivo le augura a sí misma un futuro prometedor, y de esta forma comprender el mecanismo de actuación mediante la visualización a nivel celular. También se han llevado a cabo estudios de actividad biológica sobre una línea celular tumoral, las células cancerígenas cervicouterinas HeLa, para evaluar el efecto de las variaciones estructurales introducidas en la biodistribución, citotoxicidad, etc., quedando patentes las diferencias entre los derivados de Re(I) y los de Re(I)/Au(I). Así, las especies heterobimetálicas presentan valores significativamente menores de IC50, lo que se traduce directamente en una mayor actividad anticancerígena en esta línea celular, hecho que, en parte, puede ser explicado por su aparente entrada a las mitocondrias, donde desarrollan todo su potencial, y que ha sido observado por microscopía de fluorescencia

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat