Neutrophils as major drivers of increased atherosclerosis in a murine model of chronic colitis

Background

Recent findings showed a higher risk of premature atherosclerosis and cardiovascular events in patients with inflammatory bowel disease (IBD) especially during acute flare of the chronic disease. The underlying mechanisms remain to be defined since traditional risk factors such as hypercholesterinemia are not present in these patients.

Purpose

The present study aimed to unravel the underlying pathomechanisms of enhanced atherogenesis and -progression in a murine model of colitis.

Methods

Chronic colitis was induced in male Apolipoprotein E-deficient mice (Apoe−/−) using dextran sodium sulphate (DSS) in drinking water for 2,3 or 5 cycles, while the control group received regular drinking water. Each cycle consisted of 6 days DSS application and two weeks of recovery. Aortic atherosclerotic plaque burden was determined by en face Oil Red O staining and immune cell subsets were analysed by flow cytometry in the circulation, the bone marrow, and the aorta. Neutrophil depletion was performed via i.p injection of a Ly6G-depleting antibody or respective isotype control. Bone marrow-derived neutrophils were further analysed by transcriptome analysis.

Results

Similar to IBD patients, mice with chronic colitis exhibited an increased aortic plaque burden after 15 weeks of treatment despite the absence of classical risk factors. Over time, both circulating and aortic neutrophils showed an oscillatory detection pattern with the first significant increase after the 2nd DSS administration whereby the second increase after the 3rd DSS cycle was even stronger. Also, pro-inflammatory cytokines were elevated in the plasma and specifically G-CSF showed the same oscillatory pattern with increased plasma level already after the 2nd DSS administration and an even stronger increase after the 3rd thereby pointing towards alterations in bone marrow hematopoiesis. In line, flow cytometric analyses confirmed a greater rise of hematopoietic stem and even myeloid progenitor cells compared with the 2nd DSS application in IBD mice after 3rd treatment. scRNA-Seq analysis of progenitor cells revealed changes in cell differentiation towards neutrophils and upregulation of proinflammatory genes in isolated neutrophils of DSS-treated mice. These neutrophils showed also a more adhesive phenotype revealed by increased mRNA expression of Glg1 and Selplg. Accordingly, also Sele mRNA was increased in the aorta. The reduction of circulating neutrophils by an anti-Ly6G antibody during the acute phases of colitis reduced the aortic plaque burden compared to isotype treaded mice.

Conclusion

The current findings suggest detrimental effects of chronic colitis on atherogenesis and -progression in Apoe−/− mice via increased differentiation of myeloid cells into neutrophils and the promotion of a more adhesive and proinflammatory phenotype. These modified neutrophils may act as initiators of atherogenesis by promoting the invasion of immune cells into the aortic wall.

Funding Acknowledgement

Type of funding sources: None.

Hyperglycaemia-induced degeneration of bioprosthetic valve tissue and the pivotal role of the extracellular matrix molecule biglycan

Background/Introduction

Bioprosthetic valve degeneration is a growing clinical challenge in our aging society. Especially type 2 diabetes mellitus represents a risk factor for bioprosthetic valve deterioration with likewise worldwide rising prevalence. The proteoglycan biglycan has been shown to be associated with degenerative changes of the valve in diabetic patients even though underlying mechanisms are yet unknown.

Purpose

The impact of hyperglycaemia on bioprosthetic valve tissue was analysed in an established mouse model of ectopic calcification. Thereby, the role of biglycan in bioprosthetic valve degeneration was assessed in biglycan-deficient mice (Bgn-/0) in comparison to wild type littermates (WT).

Methods

Hyperglycaemia was induced in six weeks old mice by intraperitoneal injection of streptozotocin (STZ; 55 mg/kg body weight) on five consecutive days. Blood glucose concentration was verified two weeks after treatment and bioprosthetic valve material was implanted subcutaneously. After eight weeks, phenotype of invading cells and extracellular matrix remodelling of implants were analysed with histochemical and immunohistological staining. Furthermore, gene expression of invading cells, circulating cytokines in blood plasma and calcium accumulation in the tissue were quantified.

Results

STZ treatment significantly increased blood glucose levels in both genotype groups (WT-STZ: 156 mg/dl; WT+STZ: 353 mg/dl; Bgn-/0-STZ: 142 mg/dl; Bgn-/0+STZ: 396 mg/dl). Immunohistological staining identified most of cells invading the bioprosthetic tissue and the surrounded capsule as Mac2-positive and partly positive for vimentin, whereas alpha smooth muscle actin and von Willebrand factor were only detectable sporadically. Movat pentachrome staining exhibited an altered extracellular matrix composition of collagen and proteoglycans due to hyperglycaemia, while the elastin amount remained stable. Gene expression analysis showed an increased expression of the proteoglycan decorin in hyperglycaemic mice (WT-STZ: 0.55; WT+STZ: 1.13; Bgn-/0-STZ: 0.51; Bgn-/0+STZ: 1.70). Circulating cytokines (IL-1β, IL-2, IL-5, IL-10, INF-γ, TNF-α, GM-CSF) were influenced neither by hyperglycaemia nor by the genotype of the mice. Alizarin and von Kossa staining exhibited small to moderate calcium deposits in the bioprosthetic valve tissue. A colorimetric assay showed a significantly increased calcium accumulation in WT with hyperglycaemia versus normoglycemic WT (WT-STZ: 8.96 μg/mg; WT+STZ: 18.54 μg/mg), an observation that was lost in Bgn-/0 (Bgn-/0-STZ: 9.84 μg/mg; Bgn-/0+STZ: 12.97 μg/mg).

Conclusion

Hyperglycaemia significantly promotes destructive remodelling in bioprosthetic valve material. Biglycan-deficiency limits degenerative processes associated with diabetes, suggesting that biglycan as a component of the extracellular matrix has an adverse effect in diabetes-associated bioprosthetic valve deterioration.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Dr. Rusche grant of the German Heart Foundation and the German Society for Thoracic and Cardiovascular Surgery

[The conferences of the German Society of Legal Medicine in the mirror of history]

In diesem Beitrag wird die chronologische Entwicklung der Jahrestagungen der Deutschen Gesellschaft für Rechtsmedizin (DGRM) von 1905 bis 2021 thematisiert. Dabei werden sowohl die medizinischen und wissenschaftlichen Aspekte als auch die spezifischen Probleme des Faches im Kontext der jeweiligen politischen und gesellschaftlichen Strukturen dargestellt und die Tagungskultur skizziert.

Influence of drugs on prison suicide - A retrospective case study

The prevalence of mental disorders and comorbidity with substance abuse and personality disorders is high in prisoners. Furthermore, drug abuse in prison is a widespread problem throughout prisons around the world. In this retrospective study, we analyzed the prison deaths over six years (2012-2017). For each death, we collected data of the Berlin prison system, the prison hospital and the State Institute for Forensic and Social Medicine Berlin and the Institute of Legal Medicine and Forensic Sciences, Charité Medical University Berlin. In total, 33 prisoners died during our study period, of which 24 committed suicide. In 25% of the suicide cases, forensic toxicology reports were positive for drugs without cases of lethal intoxication. A direct influence of drug intoxication on prisoner deaths and suicide was not common in our data. Small sample size, a missing control group, and the retrospective study design limit generalizability of the results.

Absence of the kinase S6k1 mimics the effect of chronic endurance exercise on glucose tolerance and muscle oxidative stress

Objective

Ribosomal protein S6 Kinase-1 (S6K1) has been linked to resistance exercise-mediated improvements in glycemia. We hypothesized that S6K1 may also play a role in regulating glycemic control in response to endurance exercise training.

Methods

S6k1-knockout (S6K1KO) and WT mice on a 60 cal% high-fat diet were trained for 4 weeks on treadmills, metabolically phenotyped, and compared to sedentary controls.

Results

WT mice showed improved glucose tolerance after training. In contrast, S6K1KO mice displayed equally high glucose tolerance already in the sedentary state with no further improvement after training. Similarly, training decreased mitochondrial ROS production in skeletal muscle of WT mice, whereas ROS levels were already low in the sedentary S6K1KO mice with no further decrease after training. Nevertheless, trained S6K1KO mice displayed an increased running capacity compared to trained WT mice, as well as substantially reduced triglyceride contents in liver and skeletal muscle. The improvements in glucose handling and running endurance in S6K1KO mice were associated with markedly increased ketogenesis and a higher respiratory exchange ratio.

Conclusions

In high-fat fed mice, loss of S6K1 mimics endurance exercise training by reducing mitochondrial ROS production and upregulating oxidative utilization of ketone bodies. Pharmacological targeting of S6K1 may improve the outcome of exercise-based interventions in obesity and diabetes.

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Absence of S6k1 upregulates oxidative substrate utilization under HFD consumption.

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S6k1 knockout mice show enhanced running performance and improved glycemia already in the sedentary state.

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Aerobic endurance exercise training of S6k1 knockout mice further improves running performance but not glycemia.

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Metabolic improvements are associated with lower rates of TCA-linked mitochondrial H₂O₂ production and increased ketogenesis.

[External post-mortem examination]

The external post-mortem examination in Germany is a non-delegable medical duty for determination of death, identity of the deceased, cause of death, manner of death, time of death and notifiable infectious diseases. Within the framework of rescue service missions the physician is limited to ascertaining that death has occurred. The determination of death must be reliable and is automatically followed by a complete external post-mortem examination of the body, if necessary by another physician. The certain signs of death are livor mortis, rigor mortis and putrefaction. Reliable features for the occurrence of death are injuries which are not compatible with life and brain death. The external post-mortem examination is the basis for the decision on whether further criminal investigations are necessary. The external post-mortem examination and the accompanying death certification must always be meticulously carried out.

Association of neighbourhood unemployment rate with incident Type 2 diabetes mellitus in five German regions

AIM

To analyse the association of neighbourhood unemployment with incident self-reported physician-diagnosed Type 2 diabetes in a population aged 45-74 years from five German regions.

METHODS

Study participants were linked via their addresses at baseline to particular neighbourhoods. Individual-level data from five population-based studies were pooled and combined with contextual data on neighbourhood unemployment. Type 2 diabetes was assessed according to a self-reported physician diagnosis of diabetes. We estimated proportional hazard models (Weibull distribution) in order to obtain hazard ratios and 95% CIs of Type 2 diabetes mellitus, taking into account interval-censoring and clustering.

RESULTS

We included 7250 participants residing in 228 inner city neighbourhoods in five German regions in our analysis. The incidence rate was 12.6 per 1000 person-years (95% CI 11.4-13.8). The risk of Type 2 diabetes mellitus was higher in men [hazard ratio 1.79 (95% CI 1.47-2.18)] than in women and higher in people with a low education level [hazard ratio 1.55 (95% CI 1.18-2.02)] than in those with a high education level. Independently of individual-level characteristics, we found a higher risk of Type 2 diabetes mellitus in neighbourhoods with high levels of unemployment [quintile 5; hazard ratio 1.72 (95% CI 1.23-2.42)] than in neighbourhoods with low unemployment (quintile 1).

CONCLUSIONS

Low education level and high neighbourhood unemployment were independently associated with an elevated risk of Type 2 diabetes mellitus. Studies examining the impact of the residential environment on Type 2 diabetes mellitus will provide knowledge that is essential for the identification of high-risk populations.

Short communication: Importance of introgression for milk traits in the German Vorderwald and Hinterwald cattle

The subject of the present study was to analyze the influence of genetic introgression on milk yield performance of the German local Vorderwald and Hinterwald cattle breeds. Deviations of milk yield, fat yield, and protein yield of cows as well as pedigree information were analyzed. A sire model was used to estimate genetic trend and effects of the migrant breeds. Migrant contributions to Vorderwald cattle were high and have been rising even in the recent past. The effects of these breeds on milk yield performance were positive. Montbéliarde cattle not only had the largest effect on milk production of Vorderwald cattle but also the highest genetic contribution to this breed. Genetic introgression with Montbéliarde continued until recently. This suggests that introgression of high-yielding breeds is still a preferred method for genetic improvement of local breeds, even though it diminishes their value for conservation. Hence, the current population management has too little focus on the preservation of genetic uniqueness. In comparison, migrant breed contributions to the Hinterwald cattle, a breed with a unique phenotype and an own niche, were moderate and almost constant over the time. For the Hinterwald cattle, no significant effect of migrant breeds could be detected, which suggests that population management has different priorities in different endangered breeds. We conclude that not only the registration of animals from local breeds but also the breeding programs themselves should be supported and need to be controlled.

The contribution of migrant breeds to the genetic gain of beef traits of German Vorderwald and Hinterwald cattle

During the past decades, migrant contributions have accumulated in many local breeds. Cross-breeding was carried out to mitigate the risk of inbreeding depression and to improve the performance of local breeds. However, breeding activities for local breeds were not as intensive and target oriented as for popular high-yielding breeds. Therefore, even if performance improved, the gap between the performance of local and popular breeds increased for many traits. Furthermore, the genetic originality of local breeds declined due to the increasing contributions of migrant breeds. This study examined the importance of migrant breed influences for the realization of breeding progress of beef traits of German Vorderwald and Hinterwald cattle. The results show that there is a high amount of migrant contributions and their effects on performance are substantial for most traits. The effect of the French cattle breed Montbéliard (p-value 0.014) on daily gain of Vorderwald bulls at test station was positive. The effects of Vorderwald ancestors (p-value for daily gain 0.007 and p-value for net gain 0.004) were positive for both traits under consideration in the population of Hinterwald cattle. Additionally, the effect of remaining breeds (p-value 0.030) on net gain of Hinterwald cattle in the field was also positive. The estimated effect of Fleckvieh ancestors on net gain of Hinterwald cattle was even larger but not significant. Breeding values adjusted for the effects of the migrant breeds showed little genetic trend.

Langjährige Be7 -Bodenluftmessungen lassen Änderung des atmosphärischen Austauschverhaltens während der letzten Jahrzehnte vermuten

An analysis covering three decades (1964-1994) of monthly Be7 ground-level-air concentration measurements at Braunschweig shows a systematic trend of the data. This trend is related to the yearly maximum/minimum concentration ratio. The observation may be due to a continuous mitigation of exchange processes between stratosphere and troposphere. This finding is commensurate with the hypothesis that, due to the growing concentration of anthropogenic infrared active gases, the heat source distribution in the stratosphere and consequently the eddy diffusivity and exchange process between stratosphere and troposphere are altered. This results in a shorter irradiation period of stratospheric air portions by cosmic rays and consequently can lower the concentration of isotopes of stratospheric origin in ground level air.

(3 + 1)-dimensional crystal and antiferromagnetic structures in CeRuSn

At 320 K, the crystal structure of CeRuSn is commensurate with the related CeCoAl-type of structure by the doubling of the c lattice parameter. However, with lowering the temperature it becomes incommensurate with x and z position parameters at all three elemental sites being modulated as one moves along the c-axis. The resulting crystal structure can be conveniently described within the superspace formalism in (3 + 1) dimensions. The modulation vector, after initially strong temperature dependence, approaches a value close to qnuc = (0 0 0.35). Below TN = 2.8 (1) K, CeRuSn orders antiferromagnetically with a propagation vector qmag = (0 0 0.175), i.e. with the magnetic unit cell doubled along the c-axis direction with respect to the incommensurate crystal structure. Ce moments appear to be nearly collinear, confined to the a-c plane, forming ferromagnetically coupled pairs. Their magnitudes are modulated between 0.11 and 0.95 μB as one moves along the c-axis.

Validation of the German Diabetes Risk Score within a population-based representative cohort

AIM

To validate the German Diabetes Risk Score within the population-based cohort of the Cardiovascular Disease - Living and Ageing in Halle (CARLA) study.

METHODS

The sample included 582 women and 719 men, aged 45-83 years, who did not have diabetes at baseline. The individual risk of every participant was calculated using the German Diabetes Risk Score, which was modified for 4 years of follow-up. Predicted probabilities and observed outcomes were compared using Hosmer-Lemeshow goodness-of-fit tests and receiver-operator characteristic analyses. Changes in prediction power were investigated by expanding the German Diabetes Risk Score to include metabolic variables and by subgroup analyses.

RESULTS

We found 58 cases of incident diabetes. The median 4-year probability of developing diabetes based on the German Diabetes Risk Score was 6.5%. The observed and predicted probabilities of developing diabetes were similar, although estimation was imprecise owing to the small number of cases, and the Hosmer-Lemeshow test returned a poor correlation (chi-squared = 55.3; P = 5.8*10⁻¹²). The area under the receiver-operator characteristic curve (AUC) was 0.70 (95% CI 0.64-0.77), and after excluding participants ≥66 years old, the AUC increased to 0.77 (95% CI 0.70-0.84). Consideration of glycaemic diagnostic variables, in addition to self-reported diabetes, reduced the AUC to 0.65 (95% CI 0.58-0.71). A new model that included the German Diabetes Risk Score and blood glucose concentration (AUC 0.81; 95% CI 0.76-0.86) or HbA(1c) concentration (AUC 0.84; 95% CI 0.80-0.91) was found to peform better.

CONCLUSIONS

Application of the German Diabetes Risk Score in the CARLA cohort did not reproduce the findings in the European Prospective Investigation into Cancer and Nutrition (EPIC) Potsdam study, which may be explained by cohort differences and model overfit in the latter; however, a high score does provide an indication of increased risk of diabetes.

Investigating associations between milk metabolite profiles and milk traits of Holstein cows

In the field of dairy cattle research, it is of great interest to improve the detection and prevention of diseases (e.g., mastitis and ketosis) and monitor specific traits related to the state of health and management. During the standard milk performance test, traditional milk traits are monitored, and quality and quantity are screened. In addition to the standard test, it is also now possible to analyze milk metabolites in a high-throughput manner and to consider them in connection with milk traits to identify functionally important metabolites that can also serve as biomarker candidates. We present a study in which 190 milk metabolites and 14 milk traits of 1,305 Holstein cows on 18 commercial farms were investigated to characterize interrelations of milk metabolites between each other, to milk traits from the milk standard performance test, and to influencing factors such as farm and sire effect (half-sib structure). The effect of influencing factors (e.g., farm) varied among metabolites and traditional milk traits. The investigations of associations between metabolites and milk traits revealed groups of metabolites that show, for example, positive correlations to protein and casein, and negative correlations to lactose and pH. On the other hand, groups of metabolites jointly associated with the investigated milk traits can be identified and functionally discussed. To enable a multivariate investigation, 2 machine learning methods were applied to detect important metabolites that are highly correlated with the investigated traditional milk traits. For somatic cell score, uracil, lactic acid, and 9 other important metabolites were detected. Lactic acid has already been proposed as a biomarker candidate for mastitis in the recent literature. In conclusion, we found sets of metabolites eligible to predict milk traits, enabling the analysis of milk traits from a metabolic perspective and discussion of the possible functional background for some of the detected associations.

Bell's palsy and sudden deafness associated with Rickettsia spp. infection in Sweden. A retrospective and prospective serological survey including PCR findings

BACKGROUND AND PURPOSE

Sixty patients with facial palsy and 67 with sudden deafness were retrospectively or prospectively examined for serological evidence of rickettsial infection; in six cases where cerebrospinal fluid was available, patients were also examined for presence of rickettsial DNA.

METHODS

Rickettsial antibodies were detected in single or paired serum samples using immunofluorescence with Rickettsia helvetica as the antigen and in four cases also using western blot. Using PCR and subsequent direct cycle sequencing, the nucleotide sequences of the amplicons (17 kDa protein gene) in cerebrospinal fluid were analysed.

RESULTS

Five out of 60 (8.3%) patients with facial palsy and eight of 67 (11.9%) with hearing loss showed confirmative serological evidence of infection with Rickettsia spp. An additional three and four patients in the facial palsy and hearing loss groups, respectively, showed evidence of having a recent or current infection or serological findings suggestive of infection. In four cases, the specificity of the reaction was confirmed by western blot. An additional 70 patients were seroreactive with IgG or IgM antibodies higher than or equal to the cut-off of 1:64, whereas 37 patients were seronegative. Only two of 127 patients had detectable antibodies to Borrelia spp. In three of six patients, rickettsial DNA was detected in the cerebrospinal fluid, where the obtained sequences (17 kDa) shared 100% similarity with the corresponding gene sequence of Rickettsia felis.

CONCLUSIONS

These results highlight the importance of considering Rickettsia spp. as a cause of neuritis, and perhaps as a primary cause of neuritis unrelated to neuroborreliosis.

The natural line width of low field nuclear magnetic resonance spectra

The authors suggest a procedure for the determination of the natural nuclear magnetic resonance line width Delta nu of liquids using an air coil system at flux densities from 25 microT to 150 microT. Even if the line broadening caused by instrumental field inhomogeneity is much higher than Delta nu, Delta nu can be found by extrapolating the measured line width's field dependency. For pure water this procedure yielded Delta nu=0.125 Hz+/-0.005 Hz. This is shown to be consistent with the smallest line width found for this sample below 25 microT using a superconducting quantum interference device-based spectrometer.