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Continuous flow chemistry is becoming an established technology platform that finds frequent application in industrial chemical manufacture with support and endorsements by the FDA for pharmaceuticals. Amongst the various advantages that are commonly cited for flow chemistry over batch processing, sustainability continues to require further advances and joint efforts by chemists and chemical engineers in both academia and industry. This short review highlights developments between 2015 and early 2021 that positively impact on the green credentials associated with flow chemistry, specifically when applied to the preparation of pharmaceuticals. An industrial perspective on current challenges is provided to whet discussion and stimulate further investment towards achieving greener modern synthetic technologies.1 Introduction2 Subject Areas and Relevant Case Studies3 Industrial Outlook on Future Sustainability Driven through Continuous Manufacturing Approaches4 Conclusions and Outlook

Conversion of N-Boc-protected quaternary proline derivatives under thermal Curtius rearrangement conditions was found to afford a series of ring-opened ketone and unsaturated pyrrolidine products instead of the expected carbamate species. The nature of the substituent on the quaternary carbon thereby governs the product outcome due to the stability of a postulated N-acyliminium species. A continuous flow process with in-line scavenging was furthermore developed to streamline this transformation and safely create products on a gram scale.

A continuous flow process is presented that couples a Curtius rearrangement step with a biocatalytic impurity tagging strategy to produce a series of valuable Cbz-carbamate products. Immobilized CALB was exploited as a robust hydrolase to transform residual benzyl alcohol into easily separable benzyl butyrate. The resulting telescoped flow process was effectively applied across a series of acid substrates rendering the desired carbamate structures in high yield and purity. The derivatization of these products via complementary flow-based Michael addition reactions furthermore demonstrated the creation of β-amino acid species. This strategy thus highlights the applicability of this work towards the creation of important chemical building blocks for the pharmaceutical and speciality chemical industries.

A continuous-flow process is presented that enables the safe generation and derivatization of benzyne under photochemical conditions. This is facilitated by a new high-power LED lamp emitting light at 365 nm. The resulting flow process effectively controls the release of gaseous by-products based on an adjustable backpressure regulator and delivers a series of heterocyclic products in a short residence time of 3 minutes. The robustness of this methodology is demonstrated for the rapid generation of benzotriazoles, 2H-indazoles and various furan-derived adducts, facilitating the preparation of these important heterocyclic scaffolds via a simple and readily scalable flow protocol.

A continuous flow process to generate [1.1.1]propellane on demand is presented rendering solutions of [1.1.1]propellane that can directly be derivatised into various bicyclo[1.1.1]pentane (BCP) species. This was realised in throughputs up to 8.5 mmol h-1 providing an attractive and straightforward access to gram quantities of selected BCP building blocks. Lastly, a continuous photochemical transformation of [1.1.1]propellane into valuable BCPs bearing mixed ester/acyl chloride moieties was developed.

A continuous photochemical process is presented that renders a series of quinoline products via an alkene isomerization and cyclocondensation cascade. It is demonstrated that a high-power LED lamp generates the desired targets with higher productivity and efficiency than a medium-pressure Hg-lamp. The scope of this tandem process is established and allows for the generation of various substituted quinolines in high yields and with throughputs of greater than one gram per hour. Finally, this effective flow process is coupled with a telescoped hydrogenation reaction to render a series of tetrahydroquinolines including the antimalarial natural product galipinine. European Commission - European Regional Development Fund Science Foundation Ireland University College Dublin 2020-10-05 JG: PDF replaced with correct versions

Continuous flow technology has played an undeniable role in enabling modern chemical synthesis, whereby a myriad of reactions can now be performed with greater efficiency, safety and control. As flow chemistry furthermore delivers more sustainable and readily scalable routes to important target structures a growing number of industrial applications are being reported. In this review we highlight the impact of flow chemistry on revitalising important chemical reactions that were either forgotten soon after their initial report as necessary improvements were not realised due to a lack of available technology, or forbidden due to unacceptable safety concerns relating to the experimental procedure. In both cases flow processing in combination with further reaction optimisation has rendered a powerful set of tools that make such transformations not only highly efficient but moreover very desirable due to a more streamlined construction of desired scaffolds. This short review highlights important contributions from academic and industrial laboratories predominantly from the last 5 years allowing the reader to gain an appreciation of the impact of flow chemistry.

This review presents a comprehensive overview on selected synthetic routes towards commercial drug compounds as published in both journal and patent literature. Owing to the vast number of potential structures, we have concentrated only on those drugs containing five-membered heterocycles and focused principally on the assembly of the heterocyclic core. In order to target the most representative chemical entities the examples discussed have been selected from the top 200 best selling drugs of recent years.

Starting from phenylhydrazine and glucose, a versatile cinnoline scaffold was obtained on a multigram scale and further derivatized. A simple continuous-flow hydrogenation process permits the conversion of selected cinnolines into their 1,4-dihydrocinnoline counterparts. These products are generated in high yields and high purities with residence times of less than one minute and, along with their cinnoline precursors, are expected to serve as valuable heterocyclic building blocks for future medicinal chemistry programs. University College Dublin 2020-10-05 JG: PDF replaced with correct version

A continuous flow platform has been developed that integrates reactive distillation with modern flow reactor technology. This has been applied to the successful flow synthesis of a series of tetrahydroquinolines generated through an InCl3-catalysed Povarov reaction between different aryl imines and cyclopentadiene that was generated by a continuous distillation from its dimeric precursor via a thermal retro Diels–Alder reaction. The developed continuous process represents a robust approach to these important heterocyclic entities which were prepared on the gram scale within less than one hour.

Herein we report the discovery of a new photochemical cascade process through a flow-based strategy for intercepting diradicals generated from simple alkenes. This continuous process delivers a series of unprecedented polycyclic reaction products. Exploring the scope of this novel process revealed that this approach is general and affords a variety of structurally complex reaction products in high yields (up to 81%), short reaction times (7 min) and high throughputs (up to 5.5 mmol h−1). A mechanistic rationale is presented that is supported by computations as well as isolation of key intermediates whose identity is confirmed by X-ray crystallography. The presented photochemical cascade process demonstrates the discovery of new chemical reactivity and complex chemical scaffolds by continuously generating and intercepting high-energy intermediates in a highly practical manner., A photochemical cascade process is reported affording complex pentacyclic scaffolds in high yields from readily available substrates. Flow processing provided high reaction control and scalability to generate gram quantities of these intriguing scaffolds for further studies.

N-heterocyclic silver carbene compounds have been extensively studied and shown to be active agents against a host of pathogenic bacteria and fungi. By incorporating hypothesized virulence targeting substituents into NHC–silver systems via salt metathesis, an atom-efficient complexation process can be used to develop new complexes to target the passive and active systems of a microbial cell. The incorporation of fatty acids and an FtsZ inhibitor have been achieved, and creation of both the intermediate salt and subsequent silver complex has been streamlined into a continuous flow process. Biological evaluation was conducted with in vitro toxicology assays showing these novel complexes had excellent inhibition against Gram-negative strains E. coli, P. aeruginosa, and K. pneumoniae; further studies also confirmed the ability to inhibit biofilm formation in methicillin-resistant Staphylococcus aureus (MRSA) and C. Parapsilosis. In vivo testing using a murine thigh infection model showed promising inhibition of MRSA for the lead compound SBC3, which is derived from 1,3-dibenzyl-4,5-diphenylimidazol-2-ylidene (NHC*).

A continuous flow process is presented, which directly converts isoxazoles into their oxazole counterparts via a photochemical transposition reaction. This results in the first reported exploitation of this transformation to establish its scope and synthetic utility. A series of various di- and trisubstituted oxazole products bearing different appendages including different heterocyclic moieties were realized through this rapid and mild flow process. Furthermore, the robustness of this approach was demonstrated by generating gram quantities of selected products while also providing insights into likely intermediates. 2020-10-05 JG: PDF replaced with correct version

A detailed account on the outcome of the thermal reaction between benzylidene phthalides and various amino acid derivatives is reported. It was discovered that the tricyclic pyrroles as previously described are not the products formed in these reactions. Instead under high-temperature conditions decarboxylated phthalamide adducts are formed within 5-10 minutes. Additionally, an unprecedented alkene transposition mechanism has been identified leading to the final products of these reactions. Royal Society School of Chemistry, University College Dublin 2020-10-06 JG: PDF replaced with correct version

Continuous flow synthesis of fine chemicals has successfully advanced from an academic niche area to a rapidly growing field of its own that directly impacts developments and applications in industrial settings. Whilst the numerous advantages of flow over batch processing are widely recognised and have led to a wider uptake of continuous flow synthesis within the community, we have reached a point where continuous flow synthesis has to transition from a stand-alone enabling technology to a readily integrated synthesis concept. Thus it is paramount to embrace a multitude of in-line analysis and purification techniques to not only allow for efficiently telescoped multi-step sequences but ultimately generate bioactivity data concomitantly on newly synthesised entities. This short review summarises the state of the art in this field and presents both challenges and opportunities that arise from this ambitious endeavour. University College Dublin

A continuous flow protocol is reported for the synthesis of 2H-indazoles via the thermal Cadogan reaction. Triethyl phosphite serves as a readily available deoxygenation reagent providing a facile entry to a series of drug-like 2H-indazoles in high chemical yields. Compared to an analogous batch approach, the flow process was advantageous as it provides for a contained environment where boiling of the reagent is suppressed by using a back-pressure regulator (BPR) which in turn leads to faster kinetics. Straightforward scale-up provided multi-gram quantities of 2H-indazoles whose further functionalisation via light-driven and regiospecific acetylation was demonstrated in flow mode.

A flow based multistep processing sequence to reliably provide the delivery of a highly functional cyclopentenone is described. The exemplification of employing solid dosing of reagents and in-line aqueous extraction has enabled an integrated workflow in a highly automated reactor setup.

We report a series of multi-step flow operations to deliver an advanced hydrazine intermediate used in the assembly of the neurotensin modulator SR 142948A. Several new reactor configurations have enabled chemical transformations that would be otherwise difficult or dangerous to perform at scale. Overall the flow approach has allowed the preparation of kilogram quantities of the required hydrazine through a short and efficient route.

A simple yet robust flow set-up for the efficient desulfurization of a series of thioimidazoles is presented, which generates the corresponding imidazole derivatives in high yields. The strategic choice of peristaltic over piston pumps allowed reliable delivery of the heterogeneous stream of the thioimidazole substrate into a T-piece where it reacted with NaNO2 in the presence of acetic acid. This approach enabled the controlled and safe formation of the reactive nitrosonium species without uncontrolled exposure to hazardous nitrous oxide by-products as observed in related batch protocols. The value of the resulting imidazole products was further demonstrated by their conversion into various esters representing new derivatives of the known analgesic etomidate through an efficient one-pot Corey–Gilman–Ganem oxidation procedure.

Propargylic amines are important multifunctional building blocks that are frequently exploited in the synthesis of privileged heterocyclic entities. Herein we report on a novel flow process that achieves the safe and effective on-demand synthesis of propargylic amines in a telescoped manner. This process minimizes exposure to hazardous azide intermediates and renders a streamlined route into these building blocks. The value of this approach is demonstrated by the rapid generation of a small selection of drug-like thiazolines that result from a high-yielding reaction cascade between propargylic amines with different aryl isothiocyanates. University College Dublin

Two series of boehmeriasin A analogs have been synthesized in short and high yielding processes providing derivatives differing either in the alkaloid's pentacyclic scaffold or its peripheral substitution pattern. These series have enabled, for the first time, comparative studies into key biological properties revealing a new lead compound with exceptionally high activity against liver cancer cell lines in the picomolar range for both well (Huh7, Hep3B and HepG2) and poorly (Mahlavu, FOCUS and SNU475) differentiated cells. The cell death was characterized as apoptosis by cytochrome-C release, PARP protein cleavage and SubG1 cell cycle arrest. Subsequent testing associated apoptosis via oxidative stress with in situ formation of reactive oxygen species (ROS) and altered phospho-protein levels. Compound 19 decreased Akt protein phosphorylation which is crucially involved in liver cancer tumorigenesis. Given its simple synthetic accessibility and intriguing biological properties this new lead compound could address unmet challenges within liver cancer therapy.

A robust approach allowing for the efficient trifluoroacetylation of a series of highly substituted pyrrolidines in a diastereoselective manner is reported. The transformation is based on a Dakin–West reaction of advanced pyrrolidine 2-carboxylic acid derivatives that can be assembled stereoselectively in four synthetic steps. Importantly, this work demonstrates how the introduction of lateral substituents on the pyrrolidine scaffold enables the generation of the desired trifluoroacetylation products, which was not possible previously due to the exclusive formation of trifluoromethylated oxazoles (vide infra). In the course of this work we succeeded for the first time in isolating and characterizing (HRMS, IR, 1H, 13C and 19F NMR, X-ray) different intermediates of the Dakin–West reaction allowing us to probe its mechanism.

A new enabling technology for performing photochemical reactions in a continuous fashion is presented. This photo-reactor is compatible with existing flow systems and can be furthermore linked to a photo-spectrometer in order to allow for real time analysis of photochemical reactions. In this communication we wish to report the profiling of this system and its application to the continuous synthesis of ibuprofen based on a photo-Favorskii rearrangement reaction of a readily available α-chloropropiophenone precursor.

An efficient reaction cascade delivering a series of pyrrolo[1,2-a]quinolines bearing phosphonate or phosphine oxide moieties is presented. This sequence exploits the in situ transformation of propargylic alcohols into transient allenes by means of a strategic [2,3]-sigmatropic rearrangement followed by trapping of the resulting allenes by an adjacent pyrrole ring. Furthermore, the initial small scale batch process was successfully translated into a continuous flow process allowing efficient preparation of selected pyrrolo[1,2-a]quinolines on multigram scale without any safety concerns due to the reaction’s inherent exothermic profile.

The efficient flow synthesis of important heterocyclic building blocks based on the 1,2,4-triazole and pyrrolo[1,2-c]pyrimidine scaffold has been achieved. Crucially, a telescoped continuous flow process was developed based on the reaction of N-formylglycine with triphosgene to deliver a stream of ethyl isocyanoacetate in situ, which subsequently yielded the desired heterocyclic entities in a telescoped reaction. Additionally, the functionalisation of the pyrrolo[1,2-c]pyrimidine core via subsequent SEAr reactions was studied revealing insight into a ‘halogen dance’ phenomenon associated with these medicinally relevant architectures.

An assembled suite of flow-based transformations have been used to rapidly scale-up the production of a novel auxin mimic-based herbicide which was required for preliminary field trials. The overall synthetic approach and optimisation studies are described along with a full description of the final reactor configurations employed for the synthesis as well as the downstream processing of the reaction streams. Royal Society Engineering School École Centrale de Marseille

Retinal arteriolar narrowing reflects aging, hypertension, chronic kidney disease (CKD), and other vascular processes. We examined the predictive value of retinal arteriolar narrowing alone and in combination with albuminuria on renal disease progression in CKD. A white CKD stage 2 to 4 cohort of 164 men and women (60.8±13.8 years) underwent retinal photography and determination of albuminuria. The calibers of all retinal arterioles were measured after digital conversion of the photographs. Cases of incident renal end points defined as 50% renal function loss and start of renal replacement therapy were identified and validated by case record reviews. Over an average period of 1410 (range, 106–1606) days, 25 patients with CKD had incident renal end points. Kaplan–Meier analysis revealed that patients with CKD within the tertile of narrowest arterioles had more renal end points (log-rank P

A continuous flow process is presented that enables the efficient synthesis and derivatization of 1,2,4-thiadiazole heterocycles. Special attention was given to the safe handling of the versatile yet hazardous trichloromethane sulfenylchloride reagent including its in-line quenching in order to eliminate malodourous and corrosive by-products. Based on this flow method gram quantities of 5-chloro-3-phenyl-1,2,4-thiadiazole were safely prepared allowing for further elaboration of this valuable building block by reaction with different nitrogen-, sulfur- and oxygen-based nucleophiles. This synthetic approach was subsequently applied to generate a series of bromophenyl-5-chloro-1,2,4-thiadiazoles providing a valuable entry towards further structural diversification on this important heterocyclic scaffold.

This review which is the second in this series summarises the most common synthetic routes as applied to the preparation of many modern pharmaceutical compounds categorised as containing a six-membered heterocyclic ring. The reported examples are based on the top retailing drug molecules combining synthetic information from both scientific journals and the wider patent literature. It is hoped that this compilation, in combination with the previously published review on five-membered rings, will form a comprehensive foundation and reference source for individuals interested in medicinal, synthetic and preparative chemistry.

INTRODUCTION Increasing evidence suggests that arterial hypertension (AHT) may begin in childhood and result in the premature development of cardiovascular disease. In view of this, we believed it would be important to investigate the early vascular changes related to early hypertension at the micro- and macrovascular levels both under normal circumstances and after cold-induced sympathetic stimulation. METHODS In a cohort of 121 adolescent subjects, we measured peripheral and central blood pressure (pBP and cBP, respectively), pulse pressure (PP), and the augmentation index (AIx), as well as retinal vascular diameters, at baseline and during a cold pressor test (CPT). We measured the central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) and calculated the retinal arteriolar-to-venular ratio (AVR). We compared macro- and microvascular alterations among normotensive (NT), prehypertensive (PHT), and hypertensive (HT) adolescents. RESULTS Of the adolescent subjects in the study, 54.5% were NT, 25.6% were PHT, and 19.8% were HT. With regard to BMI, central systolic BP (cSBP), aortic pulse pressure (AoPP), and CRAE, the PHT adolescents had values similar to those in the HT group but significantly different than those in the NT group. In the studied population, there was a positive and significant correlation of AIx with cSBP and a negative association of CRAE with both cSBP and peripheral SBP (pSBP). We describe the evolution of these parameters during and after sympathetic stimulation. CONCLUSION As compared with the prevalence of hypertension and prehypertension in large studies, involving teenagers and children, an alarming percentage (45.5%) of the adolescents in our study were HT or PHT. Higher pSBP and cSBP were associated with narrower retinal arterioles but not with changes of arterial elasticity. With particular regard to CRAE, the PHT group was more closely related to the HT group than to the NT group. There were no differences among the NT, PHT, and HT groups in the results of the CPT.

A new total synthesis of (–)-hennoxazole A is reported. The synthetic approach is based on the preparation of three similarly sized fragments resulting in a fast and convergent assembly of the natural product. The three key reactions of the synthesis include a highly stereoselective 1,5-anti aldol coupling, a gold-catalyzed alkoxycyclization reaction, and a stereocontrolled diene cross-meta­thesis. The synthesis involves integrated batch and flow chemistry methods leading to the natural product in 16 steps longest linear ­sequence and 2.8% overall yield.

Beetroot has a high concentration of inorganic nitrate, which can serially reduced to form nitrite and nitric oxide (NO) after oral ingestion. Increased renal resistive index (RRI) measured by Doppler ultrasonography is associated with higher cardiovascular mortality in hypertensive patients with reduced renal function over time defined as chronic kidney disease (CKD). Our aim was to investigate whether the supplementation of dietary nitrate by administration of beetroot juice is able to reduce blood pressure and renal resistive index (RRI) as prognostic markers for cardiovascular mortality in CKD patients. In a cross-over study design, 17 CKD patients were randomized to either a dietary nitrate load (300 mg) by highly concentrated beetroot juice (BJ) or placebo (water). Hemodynamic parameters as well as plasma nitrate concentration and RRI were measured before and 4 h after treatment. In this cohort, CKD was mainly caused by hypertensive or diabetic nephropathy. The mean eGFR was 41.6 ± 12.0 ml/min/m 2 . Plasma nitrate concentrations were significantly increased after ingestion of BJ compared to control. Peripheral systolic and diastolic blood pressure as well as mean arterial pressure (MAP) were significantly reduced secondary to the dietary nitrate load compared to control (e.g. ΔMAP BJ = −8.2 ± 7.6 mmHg vs. ΔMAP control = −2.2 ± 6.0 mmHg, p = 0.012). BJ also led to significantly reduced RRI values (ΔRRI BJ = −0.03 ± 0.04 versus ΔRRI control = 0.01 ± 0.04; p = 0.017). Serum potassium levels were not altered secondary to the treatment. In this study, administration of the nitrate donor BJ led to significantly reduced RRI values and peripheral blood pressure which might be explained by release of the vasodilatator NO after oral intake. Whether supplementation of dietary nitrate in addition to routine pharmacologic therapy is able to decelerate progression of cardiovascular and renal disease in CKD, remains to be investigated.

The synthesis of diazonium salts is historically an important transformation extensively utilized in dye manufacture. However the highly reactive nature of the diazonium functionality has additionally led to the development of many new reactions including several carbon-carbon bond forming processes. It is therefore highly desirable to determine optimum conditions for the formation of diazonium compounds utilizing the latest processing tools such as flow chemistry to take advantage of the increased safety and continuous manufacturing capabilities. Herein we report a series of flow-based procedures to prepare diazonium salts for subsequent in-situ consumption.

Using continuous-flow techniques, a small collection of 2H-azirines was prepared from oxime precursors via mesylation and base-promoted cyclisation. The 2H-azirines were either isolated after in-line purification or derivatised into a selection of 2-substituted aziridines through a telescoped reaction sequence involving nitrile, trifluoromethyl, or hydride nucleophilic addition. Importantly, these 2-substituted aziridines were produced with high cis diastereoselectivity providing access to small chiral heterocyclic entities that hold promise for medicinal chemistry programs because of their druglike features.

The implementation of continuous flow processing as a key enabling technology has transformed the way we conduct chemistry and has expanded our synthetic capabilities. As a result many new preparative routes have been designed towards commercially relevant drug compounds achieving more efficient and reproducible manufacture. This review article aims to illustrate the holistic systems approach and diverse applications of flow chemistry to the preparation of pharmaceutically active molecules, demonstrating the value of this strategy towards every aspect ranging from synthesis, in-line analysis and purification to final formulation and tableting. Although this review will primarily concentrate on large scale continuous processing, additional selected syntheses using micro or meso-scaled flow reactors will be exemplified for key transformations and process control. It is hoped that the reader will gain an appreciation of the innovative technology and transformational nature that flow chemistry can leverage to an overall process.

Propargylic alcohols are converted into tricyclic pyrroloquinolines in the presence of chlorophosphine and phosphite species.

Baseline blood pressure (BP) is the strongest known determinant of progression to hypertension, but for an individualized prediction of the incidence of hypertension, the identification of additional biomarkers is crucial. In animal models of hypertension, renal nitric oxide (NO) handling modifies the systemic BP responses prior to the development of hypertension. This study aimed to evaluate whether urinary NO metabolites (NOx) predict the progression of hypertension in normotensive subjects. Among 62 participants enrolled in the Flemish Study on Environment, Genes and Health Outcomes, we assessed progression to hypertension over 4.6 years. In a case-control design, 49 normotensive subjects including 10 subjects with high-normal blood pressure were enrolled of whom 25 remained normotensive (controls), whereas 24 'progressed' to hypertension (progressors). Thirteen hypertensive patients served as negative controls. Urinary NOx concentration, renal function and the urinary excretion of electrolytes were assessed at baseline and follow-up. At baseline, progressors showed higher BP values than controls and urinary NOx concentration was significantly lower in progressors as compared to the normotensive controls (p < 0.01). In all initially normotensive subjects baseline urinary NOx concentration was associated with follow-up BP (r=-0.55, p < 0.001) and the relative increase of BP over time (r=-0.47, p < 0.001). In progressors baseline urinary NOx was associated with follow-up BP (r=-0.52, p < 0.009) and the relative increase of BP over time (r=-0.44, p=0.033). Baseline urinary NOx and BP were independent predictors for the relative BP increase. A urinary NOx threshold of < 130.5 mg/L predicted 75% of all progressors. In context with high-normal baseline BP, 87.5% of all progressors were identified. These findings indicate that urinary NO metabolites are associated with BP development in normotensive subjects. Moreover, urinary NOx predicts the progression to hypertension independent of baseline BP suggesting urinary NOx as a biomarker for individual new-onset hypertension. ispartof: European Journal of Cardiovascular Prevention and Rehabilitation vol:18 issue:4 pages:656-663 ispartof: location:England status: published

Inflammation plays an important role in host defenses against infectious agents and injury, but it also contributes to the pathophysiology of atherosclerosis. Signal transducer and activated transcription 1 (STAT1) has been identified as a point of convergence for the cross talk between the pro-inflammatory cytokine interferon γ (IFNγ) and the Toll-like receptor-4 (TLR4) ligand LPS in immune cells. However, there is no information available on the role of STAT1 in TLR4-mediated progression of atherosclerosis and on potential synergism between lipopolysaccharides (LPS) and IFNγ signaling in cells from the vasculature. Cultured human microvascular endothelial cells (HMECs) exposed to LPS activated STAT1 in a delayed manner that was inhibited by cycloheximide treatment. Pretreatment of HMECs as well as primary vascular smooth muscle cells (VSMCs) with IFNγ followed by LPS resulted in a significant increase in STAT1 phosphorylation compared with both factors alone. Increased STAT1 protein levels, strictly mediated by IFNγ, correlated with the augmented STAT1 phosphorylation that was absent in TLR4−/−cells. As assessed by PCR, Western analysis, and ELISA, this coincided with increased expression of the chemokine interferon gamma-induced protein 10 kDa (IP-10) and the adhesion molecule ICAM-1 in a TLR4-dependent manner.The STAT1-inhibitor fludarabine markedly reduced these effects as well as IFNγ and LPS-dependent adhesion of U937 cells to endothelial cells, emphasizing the potential importance of STAT1 in the integration of both signals. With the established roles of IFNγ and TLRs in atherosclerotic pathology, the STAT1-dependent signal integration between IFNγ and TLR in ECs and VSMCs in response to exogenous and endogenous atherogenic ligands could result in amplification of pro-inflammatory responses in the damaged vessel and be a novel mechanism involved in the initiation and progression of atherosclerosis.

The bisoxazole containing natural product O-methyl si- phonazole was assembled using a suite of microreactors via a flow- based approach in concert with traditional batch methods. The use of a toolbox of solid-supported scavengers and reagents to aid puri- fication afforded the natural product in a total of nine steps.

Pan CR, Schmaderer C, Roos M, von Eynatten M, Sollinger D, Lutz J, Heemann U, Baumann M. Comparing aortic stiffness in kidney transplant recipients, hemodialysis patients, and patients with chronic renal failure. Clin Transplant 2011: 25: E463–E468. © 2011 John Wiley & Sons A/S. Abstract: Background: The poor cardiovascular survival of patients with renal insufficiency is improved by transplantation. Carotid-femoral pulse wave velocity (PWV) is able to predict independently overall and cardiovascular mortality. PWV is elevated in renal insufficiency. Consequently, PWV may change according to the improvement in renal function after kidney transplantation. Methods: In a cross-sectional setting, PWV was determined in 40 renal transplant recipients (RTx) and compared to the PWV of 40 age- and gender-matched patients with comparable renal insufficiency (CKD) and 40 age- and gender-matched hemodialysis patients (HD). Results: RTx and CKD patients had comparable eGFR (RTx: 42.9 ± 18.4, CKD: 48.3 ± 29.1 mL/min/1.73 m2) and protein/creatinine ratio (RTx: median 172.5, 25th percentile 97.75, 75th percentile 344.5, CKD: median 183.272, 25th percentile 100.00, 75th percentile 470.00 mg/g creatinine). There was no significant difference in PWV between RTx 3–12 months post-transplant and CKD or HD patients (RTx: 9.65 ± 1.57, CKD: 9.98 ± 3.91, HD: 10.27 ± 2.89 m/s; n = 20 pairs). Similarly, PWV in transplant patients >12-month post-transplant was similar to that of CKD and HD patients (RTx: 9.71 ± 2.23, CKD: 9.36 ± 2.74, HD: 9.84 ± 3.41 m/s; n = 20 pairs). Discussion: We could not detect significant differences in PWV comparing RTx with age- and gender-matched CKD patients.

Background Spontaneously hypertensive rats (SHRs) are characterized by capillary rarefaction, which may contribute to blood pressure elevation. We hypothesized that capillary rarefaction involves a suppressed angiogenesis; renin inhibition influences anti-angiogenesis homeostasis by acting on angiopoietins; transient renin blockade reduces anti-angiogenesis thereby ameliorating long-lasting blood pressure and cardiac hypertrophy in SHRs. Methods First, serum angiopoietin-1 and angiopoietin-2 were measured in 2-month old normotensive Wistar-Kyoto rats (WKYs) and SHRs after renin inhibition (aliskiren: 1 and 10mg/kg per day) or placebo. Second, 4-week old SHRs were prehypertensively treated with aliskiren (1 and 10mg/kg per day) or placebo for 4 weeks. After 4 weeks of 'drug holiday' 12-week old SHRs were given L-nitro-arginine methyl ester (L-NAME) (25mg/kg per day) for a 4-week interval to promote capillary rarefaction. Thereafter, mean arterial pressure (MAP), cardiacremodeling, capillary density, pAkt/Akt as marker for cellular survival, pro-angiogenic genes and systemic angiopoietins were investigated. Results Baseline angiopoietin levels were similar between WKYs and SHRs. Renin inhibition increased angiopoietin-1 in SHR and reduced angiopoietin-2 in both WKY and SHR blood pressure independently. Prehypertensive renin inhibition reduced MAP and cardiac hypertrophy in adult SHRs. This was associated with higher cardiac capillary density, pAkt/Akt, pro-angiogenic expression pattern and serum angiopoietin-1, whereas angiopoietin-2 was lower as compared to vehicle-pretreated SHRs. These results were independent of prehypertensive blood pressure lowering by aliskiren. Conclusion We conclude that renin inhibition modulates anti-angiogenesis signaling independently of blood pressure by increasing angiopoietin-1/angiopoietin-2 ratio. This promotes in SHR stabilization of endothelial cells, favors pro-angiogenic action and consequently results in higher capillary density. J Hypertens 29: 266-272

Background/aims Measurement of pulse wave velocity (PWV) in large vessels has been used extensively in clinical practice as an indirect measure of arterial stiffness and an indicator of cardiovascular risk factors. Arterial stiffness increases with age and in coronary artery disease. An in vivo clinical method to characterise arterial stiffness of the central microcirculation was developed. Methods Time-dependent alterations of retinal vessel diameter were examined by the dynamic vessel analyzer in a randomly chosen eye of 10 young (26.0 (23.5, 27.0) years old (median (1st quartile, 3rd quartile)) and 10 old (67.0 (61.3, 69.5)) years old) healthy volunteers. Two segments of a retinal artery were measured simultaneously. The distance between the segments was measured using retinal photographs. The data were filtered and analysed using signal analysis methods in order to calculate PWV in the assessed retinal artery (rPWV). Results rPWV differed significantly between young (21.5 (17.9, 4.6) mm/s) and old (243.8 (186.1, 347.7) mm/s) volunteers: (p=0.0001, Mann–Whitney test with Bonferroni correction). Conclusions This study demonstrates a higher rPWV in elderly people than in young people. Therefore this new parameter resembles large artery PWV. This suggests that dynamic in vivo imaging of the central microcirculation enables the measurement of local microvascular stiffness with a commercially available medical device.

This paper presents process characteristics and proof of concept reactions for a newly developed microreactor system, termed the Cambridge Disc Microreactor (CDM), using plastic microcapillary flow discs (MFDs). These flat reactor discs were constructed from a flexible, temperature resilient, solvent resistant fluoropolymer microcapillary film (MCF) comprising 10 parallel capillary channels with mean hydraulic diameters typically between 150 and 400 μm. The MFDs were heated inside the microreactor via conductive heat transfer from two heated surfaces, which were in contact with the flat outer surfaces of the disc. This allowed continuous flow processing of liquid phase reactions through the reactor at elevated temperatures and pressures at a precisely controlled residence time. The process characteristics of the reactor system were established experimentally by investigating the hydraulic response and the temperature profile or modeled analytically such that the residence time characteristics inside the d...

Background Little data exist on the relationship between potassium level and infarct size after ST-segment elevation acute myocardial infarction (STEMI). We investigated the influence of potassium levels on infarct size measured with single photon emission computed tomography (SPECT) in patients with STEMI after mechanical reperfusion. Methods The study included 598 patients. Potassium measurements at baseline and 2 SPECT examinations, at baseline and 7–14 days after intervention, were performed. Infarct size in the 7–14 days SPECT and salvage index were the primary outcome analyses. Results Tertiles of baseline potassium were: 4.37 mEq/L (3rd tertile). In potassium 1st, 2nd and 3rd tertiles, the infarct size in the 7–14 days SPECT (median [25th–75th percentiles]) was 9.0% [2.0%–21.8%], 10.0% [3.5%–22.0%] and 12.0% [5.0%–25.5%] of left ventricle (p = 0.026); salvage index was 0.50 [0.26–0.84], 0.56 [0.26–0.81] and 0.40 [0.23–0.75] (p = 0.09). Patients with anterior infarction in upper potassium tertile had greater infarct size compared with patients in lower potassium tertile (p = 0.049). After adjustment in multivariable analysis, potassium was an independent correlate of infarct size in the 7–14 days SPECT (p = 0.05). Conclusions In patients with STEMI, higher baseline potassium levels are associated with a larger scintigraphic infarct size.

The safe and reliable use of various fluorination methods including nucleophilic fluorination (DAST), trifluoromethylation (Ruppert's reagent) and electrophilic fluorination (Selectfluor®) in a continuous-flow microreactor is reported. Special attention was given to the use of in-line scavenging procedures in order to obtain clean products without the need for further purification.