Cardiovascular phenotyping of the first mouse model of Sarcoidosis

Introduction

Sarcoidosis is a potentially life-threatening, inflammatory, granulomatous disease that affects multiple organs including the heart. Heretofore, its unknown etiology had hindered the creation of experimental models and the understanding of the molecular mechanisms of pathogenesis behind it.

Purpose

To extensively phenotype the heart of the first mouse model of sarcoidosis created through deletion of the tuberous sclerosis 2 (Tsc2) gene in the CD11c-positive macrophage population.

Methods

Tsc2 fl/fl CD11c Cre+ (Tsc2-KO; n=7) and Tsc2 fl/fl CD11c Cre- (Tsc2-WT; n=7) mice were subjected to echocardiography at 25 weeks of age (woa) to assess myocardial dimensions and function. Hearts of 13 and 25woa animals were subjected to histological and immunological stains to assess tissue changes, subtype inflammatory infiltrates and examine the localization of key proteins shown to be re-distributed in patients.

Results

At 13 woa, Tsc2-KO animals show inflammatory infiltrates; subtyped mainly as macrophages as well as evidence of myocyte destruction. At 25 woa, the number of inflammatory cells is significantly higher and there is heavy fibrotic replacement primarily in the septum and trabeculae. Older animals also show giant cells and non-necrotizing granulomas. The hearts show heterogeneous gap junction remodeling known to constitute an arrhythmogenic substrate and lack of immunoreactive signal for the desmosomal protein plakoglobin from the cell-cell junctions just as described in patients. The left ventricular ejection fraction and LV morphology was not significantly different between the two groups (EF: 64±4% in Tsc2-KO vs 64±2% in Tsc2-WT; LV end-systolic diameter: 4.51±0.54 mm in Tsc2-KO vs 4.59±0.29 mm in Tsc2-WT). However, there was a strong trend towards increasing filling pressure (E/e'ratio; 14.24±4.01 vs 12.15±2.54) and mean pulmonary pressure (21±6 vs 18±3 mmHg) in Tsc2-KO mice compared to controls suggesting diastolic dysfunction.

Conclusion

Hearts of the Tsc2 fl/fl CD11c Cre+ animals show a phenotype highly reminiscent of cardiac sarcoidosis in patients. We anticipate that this model will be very useful in deciphering molecular mechanisms of pathogenesis as well as testing much-needed mechanism-based therapies.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation - PG/18/27/33616

Improvement of diet sustainability with increased level of organic food in the diet: findings from the BioNutriNet cohort

BACKGROUND

Organic food consumption has steadily increased over the past decade in westernized countries.

OBJECTIVE

The aim of this study, based on observational data, was to compare some sustainability features of diets from consumers with varying levels of organic food.

METHODS

The diet sustainability among 29,210 participants of the NutriNet-Santé study was estimated using databases developed within the BioNutriNet project. Four dimensions (nutrition, environment, economy, and toxicology) of diet sustainability were assessed using: 1) nutritional indicators through dietary intakes and dietary scores, and BMI; 2) environmental indicators (greenhouse gas emissions, cumulative energy demand, and land occupation); 3) economic indicators via diet monetary costs; and 4) estimated daily food exposures to 15 pesticides. Adjusted means (95% CI) across weighted quintiles of organic food consumption in the diet were estimated via ANCOVA. Breakdown methods were used to disentangle the contribution of the production system (organic compared with conventional) from the dietary pattern in the variation of diet-related environmental impacts, monetary costs, and pesticide exposure, between the 2 extreme quintiles.

RESULTS

Higher organic food consumption was associated with higher plant-food and lower animal-food consumption, overall nutritional quality (higher dietary scores), and lower BMI. Diet-related greenhouse-gas emissions, cumulative energy demand, and land occupation gradually decreased with increasing organic food consumption, whereas total diet monetary cost increased. Diet exposure to most pesticides decreased across quintiles.

CONCLUSIONS

Diets of high organic food consumers were generally characterized by strong nutritional and environmental benefits. The latter were mostly driven by the low consumption of animal-based foods, whereas the production system was responsible for the higher diet monetary costs, and the overall reduced dietary pesticide exposure.

Reasons for taking radiographs in general dental practice in Dar-es-Salaam, Tanzania

This study investigated the reasons why dental practitioners at the Muhimbili Dental OPD clinic in Dar-es-Salaam take radiographs. Information was obtained from medical records at the Department of Dental Radiology for an eighteen month period, during which 28,171 patients were seen at the hospital, and of which 2,672 (9.48 per cent) were radiographed. The main reasons for taking radiographs (percentages) was to detect fractures (17.2), tumours (14.1), caries (12.5), impacted teeth (12.2), periodontal disease (11.3), and non-specific dental pain (10.4). Radiographs were also taken for orthodontic (7.0 per cent) and endodontic (6.8 per cent) reasons. Some of the reasons for taking radiographs such as hypersensitive teeth, apicectomy, neuralgia and xerostomia were previously unheard of, indicating an increasing diversity of dental services. In conclusion, there is a need to increase the utilisation of dental radiographs from the present modest level in order to meet the growing need of the increasingly informed dental population in Dar-es-Salaam.