Histamine is metabolized by several enzymes
in vitro
and
in vivo
. The relevance of this metabolism in the mammalian heart
in vivo
is unclear. However, histamine can exert positive inotropic effects ...(PIE) and positive chronotropic effects (PCE) in humans via H
2
-histamine receptors. In transgenic mice (H
2
-TG) that overexpress the human H
2
receptor in cardiomyocytes but not in wild-type littermate mice (WT), histamine induced PIE and PCE in isolated left or right atrial preparations. These H
2
-TG were used to investigate the putative relevance of histamine degrading enzymes in the mammalian heart. Histidine, the precursor of histamine, increased force of contraction (FOC) in human atrial preparations. Moreover, histamine increased the phosphorylation state of phospholamban in human atrium. Here, we could detect histidine decarboxylase (HDC) and histamine itself in cardiomyocytes of mouse hearts. Moreover, our data indicate that histamine is subject to degradation in the mammalian heart. Inhibition of the histamine metabolizing enzymes diamine oxidase (DAO) and monoamine oxidase (MAO) shifted the concentration response curves for the PIE in H
2
-TG atria to the left. Moreover, activity of histamine metabolizing enzymes was present in mouse cardiac samples as well as in human atrial samples. Thus, drugs used for other indication (e.g. antidepressants) can alter histamine levels in the heart. Our results deepen our understanding of the physiological role of histamine in the mouse and human heart. Our findings might be clinically relevant because we show enzyme targets for drugs to modify the beating rate and force of the human heart.
Aim
Several genetically modified mice models were studied so far to investigate the role of cardiac calsequestrin (CSQ2) for the contractile function of the ventricle and for the occurrence of ...ventricular tachycardia. Using a CSQ2 knockout mouse, we wanted to study also the atrial function of CSQ2.
Methods
The influence of CSQ2 on atrial function and, for comparison, ventricular function was studied in isolated cardiac preparations and by echocardiography as well as electrocardiography in mice with deletion of CSQ2.
Results
Using deletion of exon 1, we have successfully generated a constitutive knockout mouse of the calsequestrin 2 gene (CSQ2−/−). CSQ2 protein was absent in the heart (atrium, ventricle), but also in oesophagus and skeletal muscle of homozygous knockout mice. In 6‐month‐old CSQ2−/− mice, relative left atrial weight was increased, whereas relative heart weight was unchanged. The staircase phenomena in paced left atrial preparations on force of contraction and the post‐rest potentiation were different between wild type and CSQ2−/− indicative for a decreased sarcoplasmic Ca2+ load and supporting an important role of CSQ2 also in the atrium. The incidence of arrhythmias was increased in CSQ2−/−. In 2‐year‐old CSQ2−/− mice, cardiac hypertrophy and heart failure were noted possibly as a result of chronically increased cytosolic Ca2+ levels.
Conclusion
These data suggest a functional role of CSQ2 not only in the ventricle but also in the atrium of mammalian hearts. Loss of CSQ2 function can cause not only arrhythmias, but also cardiac hypertrophy and heart failure.
Clonal hematopoiesis of indeterminate potential (CHIP) is associated with increased risk of atherosclerotic cardiovascular disease, and mouse experiments suggest that CHIP related to Tet2 loss of ...function in myeloid cells accelerates atherosclerosis via augmented interleukin (IL) 1β signaling.
To assess whether individuals with CHIP have greater cardiovascular event reduction in response to IL-1β neutralization in the Canankinumab Anti-inflammatory Thrombosis Outcomes Trial (CANTOS).
This randomized clinical trial took place from April 2011 to June 2017 at more than 1000 clinical sites in 39 countries. Targeted deep sequencing of genes previously associated with CHIP in a subset of trial participants using genomic DNA prepared from baseline peripheral blood samples were analyzed. All participants had prior myocardial infarction and elevated high-sensitivity C-reactive protein level above 0.20 mg/dL. Analysis took place between June 2017 and December 2021.
Canakinumab, an anti-IL-1β antibody, given at doses of 50, 150, and 300 mg once every 3 months.
Major adverse cardiovascular events (MACE).
A total of 338 patients (8.6%) were identified in this subset with evidence for clonal hematopoiesis. As expected, the incidence of CHIP increased with age; the mean (SD) age of patients with CHIP was 66.3 (9.2) years and 61.5 (9.6) years in patients without CHIP. Unlike other populations that were not preselected for elevated C-reactive protein, in the CANTOS population variants in TET2 were more common than DNMT3A (119 variants in 103 patients vs 86 variants in 85 patients). Placebo-treated patients with CHIP showed a nonsignificant increase in the rate of MACE compared with patients without CHIP using a Cox proportional hazard model (hazard ratio, 1.32 95% CI, 0.86-2.04; P = .21). Exploratory analyses of placebo-treated patients with a somatic variant in either TET2 or DNMT3A (n = 58) showed an equivocal risk for MACE (hazard ratio, 1.65 95% CI, 0.97-2.80; P = .06). Patients with CHIP due to somatic variants in TET2 also had reduced risk for MACE while taking canakinumab (hazard ratio, 0.38 95% CI, 0.15-0.96) with equivocal difference compared with others (P for interaction = .14).
These results are consistent with observations of increased risk for cardiovascular events in patients with CHIP and raise the possibility that those with TET2 variants may respond better to canakinumab than those without CHIP. Future studies are required to further substantiate this hypothesis.
ClinicalTrials.gov Identifier: NCT01327846.
Background
Improved Phase 2 study designs may increase success rates in late stage AD trials. Varoglutamstat (PQ912) is an oral small molecule glutaminyl cyclase inhibitor designed to address several ...key disease mechanisms. A Phase 2A study (NCT02389413) of 120 early AD patients treated for 12 weeks provided preliminary evidence of safety and tolerability, and effects on working memory, CSF biomarkers, and synaptic function (EEG theta‐power).
Objective
To design a well‐powered, safe, and efficient study of varoglutamstat in early AD incorporating adaptive dose selection in Phase 2A, a futility analysis testing pharmacological, biological and cognitive criteria, and a seamless transition to a larger Phase 2B study investigating longer‐term efficacy and safety.
Methods
An efficient and safe selection rule across 3 descending doses (600mg, 300mg, 150 mg BID) was established using a continuously monitored Pocock safety boundary targeting a set of treatment emergent AE’s of interest. Well‐powered stage‐gate criteria at a planned interim futility analysis included thresholds for target occupancy in plasma, and would detect negative effects on a cognitive composite or absence of benefit on EEG theta‐power. The Phase 2B study was powered to detect an effect size of 0.7 points on the Clinical Dementia Rating – Sum of Boxes score at 18 months, an established approvable endpoint.
Results
The on‐going Phase 2A adaptive dose‐finding trial (NCT03919162) is randomizing 180 subjects with MCI or mild probable AD, initially to 24+ weeks of 600mg varoglutamstat dose or placebo, BID. If the safety boundary is hit, the dose will be discontinued and all subjects titrated down, with similar sequential testing of lower doses as needed. The interim futility analysis will occur when the first 180 randomized subjects have been on study for at least 24 weeks. If this stage‐gate is passed, Phase 2B will enroll 234 additional patients to achieve 414 total patients treated for 72 weeks at full dose of varoglutamstat or placebo.
Conclusion
This novel study design enables adaptive dose selection, an early interim futility analysis, and longer‐term determination of cognitive and functional efficacy, and should support robust proof‐of‐concept for varoglutamstat using a total sample of 414 subjects treated for 72 weeks.
Previously, we have shown that CyPPA (cyclohexyl-2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl-amine), a pharmacological small-conductance calcium-activated potassium (SK)-channel positive ...modulator, antagonizes lipopolysaccharide (LPS)-induced cytokine expression in microglial cells. Here, we aimed to test its therapeutic potential for brain-controlled sickness symptoms, brain inflammatory response during LPS-induced systemic inflammation, and peripheral metabolic pathways in mice.
Mice were pretreated with CyPPA (15 mg/kg IP) 24 hours before and simultaneously with LPS stimulation (2.5 mg/kg IP), and the sickness response was recorded by a telemetric system for 24 hours. A second cohort of mice were euthanized 2 hours after CyPPA or solvent treatment to assess underlying CyPPA-induced mechanisms. Brain, blood, and liver samples were analyzed for inflammatory mediators or nucleotide concentrations using immunohistochemistry, real-time PCR and Western blot, or HPLC. Moreover, we investigated CyPPA-induced changes of UCP1 expression in brown adipose tissue (BAT)-explant cultures.
CyPPA treatment did not affect LPS-induced fever, anorexia, adipsia, or expression profiles of inflammatory mediators in the hypothalamus or plasma or microglial reactivity to LPS (CD11b staining and CD68 mRNA expression). However, CyPPA alone induced a rise in core body temperature linked to heat production via altered metabolic pathways like reduced levels of adenosine, increased protein content, and increased UCP1 expression in BAT-explant cultures, but no alteration in ATP/ADP concentrations in the liver. CyPPA treatment was accompanied by altered pathways, including NFκB signaling, in the hypothalamus and cortex, while circulating cytokines remained unaltered.
Overall, while CyPPA has promise as a treatment strategy, in particular according to results from in vitro experiments, we did not reveal anti-inflammatory effects during severe LPS-induced systemic inflammation. Interestingly, we found that CyPPA alters metabolic pathways inducing short hyperthermia, most likely due to increased energy turnover in the liver and heat production in BAT.
•Practices on animal health monitoring have been investigated.•We focused on Informational Resources that farmers use to pilot animal health.•Six types of informational resources are used by farmers ...and cited by their advisors.•Farmers primarily use informal sensory indicators based on daily herd observations.•Under-estimated sensory indicators could lead to a gap of communication.
Managers of health in livestock systems are asked to shift from a curative approach to a more preventive approach. This change requires sociological and technical reconfiguration and raises the issue of how changes are implemented by farmers and their technical support ecosystem (advisors, trainers, veterinarians). Here, we report work conducted in western France by an Agricultural European Innovation Partnership Operational Group bringing together animal scientists and sociologists to advance knowledge on animal health in a range of livestock sectors, i.e. dairy cattle, beef cattle, small ruminants (sheep, goats), poultry and pigs. In this study, our aim was to answer this question: what are the Informational Resources (I.R.) that farmers use to promote animal health of their herds? First, we used a survey to characterize 129 I.R. used by advisors, then, we used statistical analysis to classify these I.R. into six clusters. Second, we organized eight focus-group sessions that involved a total of 50 farmers from across all livestock sectors to find out how they mobilize the I.R. and what they see as important for animal health monitoring practice. Finally, we performed individual interviews with 42 farmers to expand the data captured in the collective focus groups. Results showed that farmers and advisors have a broad and diverse range of I.R. to help monitor animal health. We identified six clusters of I.R.: regulatory tools, periodic reports, tools for farmer-led monitoring, tools and indicators for national reference datasets, slaughterhouse and laboratory indicators, and training delivered to farmers. During focus group, livestock farmers identified some of their I.R. within these clusters but they also cited other daily routines that help them monitor animal health that were not cited by advisors. We found that farmers mainly use sensory indicators (typically smell, sight, touch) in their daily practice whereas advisors mainly use relatively sophisticated retrospective monitoring tools. Farmers also cited the importance of indicators that can rapidly objectify any change in animal condition, behavior, or health. This work finds a split in the distribution of animal health management roles, with farmers implementing daily checks whereas advisors run periodic health surveillance, thus revealing differentiated roles and needs between farmers and their advisors.
The alkane-assimilating yeast
Yarrowia lipolytica degrades very efficiently hydrophobic substrates such as
n-alkanes, fatty acids, fats and oils for which it has specific metabolic pathways. An ...overview of the oxidative degradation pathways for alkanes and triglycerides in
Y. lipolytica is given, with new insights arising from the recent genome sequencing of this yeast. This includes the interaction of hydrophobic substrates with yeast cells, their uptake and transport, the primary alkane oxidation to the corresponding fatty alcohols and then by different enzymes to fatty acids, and the subsequent degradation in peroxisomal β-oxidation or storage into lipid bodies. Several enzymes involved in hydrophobic substrate utilisation belong to multigene families, such as lipases/esterases (
LIP genes), cytochromes P450 (
ALK genes) and peroxisomal acyl-CoA oxidases (
POX genes). Examples are presented demonstrating that wild-type and genetically engineered strains of
Y. lipolytica can be used for alkane and fatty-acid bioconversion, such as aroma production, for production of SCP and SCO, for citric acid production, in bioremediation, in fine chemistry, for steroid biotransformation, and in food industry. These examples demonstrate distinct advantages of
Y. lipolytica for their use in bioconversion reactions of biotechnologically interesting hydrophobic substrates.
Colorectal cancer (CRC) has a high prevalence in western countries. Diagnosis and treatment of CRC is complex and requires multidisciplinary collaboration across the interface of health care sectors. ...In Germany, a new nationwide established program aims to provide quality information of healthcare delivery across different sectors. Within this context, this study describes the development of a set of quality indicators charting the whole pathway of CRC-care including data specifications that are necessary to operationalize these indicators before practice testing.
Indicators were developed following a systematic 10 step modified 'RAND/UCLA Appropriateness Method' which involved a multidisciplinary panel of thirteen participants. For each indicator in the final set, data specifications relating to sources of quality information, data collection procedures, analysis and feedback were described.
The final indicator set included 52 indicators covering diagnostic procedures (11 indicators), therapeutic management (28 indicators) and follow-up (6 indicators). In addition, 7 indicators represented patient perspectives. Primary surgical tumor resection and pre-operative radiation (rectum carcinoma only) were perceived as most useful tracer procedures initiating quality data collection. To assess the quality of CRC care across sectors, various data sources were identified: medical records, administrative inpatient and outpatient data, sickness-funds billing code systems and patient survey.
In Germany, a set of 52 quality indicators, covering necessary aspects across the interfaces and pathways relevant to CRC-care has been developed. Combining different sectors and sources of health care in quality assessment is an innovative and challenging approach but reflects better the reality of the patient pathway and experience of CRC-care.
The consumers' demand for natural flavour and fragrances rises. To be natural, compounds have to result from the extraction of natural materials and/or to be transformed by natural means such as the ...use of enzymes or whole cells. Fungi are able to transform some fatty acids into lactones that can thus be natural. Although some parts of this subject have been reviewed several times, the present article proposes to review the different pathways utilised, the metabolic engineering strategies and some current concerns on the reactor application of the transformation including scaling up data. The main enzymatic steps are hydroxylation and β-oxidation in the traditional way, and lactone desaturation or Baeyer-Villiger oxidation. Although the pathway to produce γ-decalactone is rather well known, metabolic engineering strategies may result in significant improvements in the productivity. For the production of other lactones, a key step is the hydroxylation of fatty acids. Beside the biotransformation, increasing the production of the various lactones requires from biotechnologists to solve two main problems which are the toxicity of lactones toward the producing cell and the aeration of the emulsified reactor as the biochemical pathway is very sensitive to the level of available oxygen. The strategies employed to resolve these problems will be presented.
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