In vivo investigation of Lcr35® anti-candidiasis properties in Caenorhabditis elegans reveals the involvement of highly conserved immune pathways

Lactic acid bacteria, including the microorganisms formerly designated as Lactobacillus, are the major representatives of Live Biotherapeutic Microorganisms (LBM) when used for therapeutic purposes. However, in most cases, the mechanisms of action remain unknown. The antifungal potential of LBM has already been demonstrated using preclinical models (cell cultures, laboratory animals). Understanding their mechanisms of action is strategic for the development of new therapeutics for humans. Here, Caenorhabditis elegans was used as an in vivo model to analyze pro-longevity, anti-aging and anti-candidiasis effects of the LBM Lacticaseibacillus rhamnosus (formerly Lactobacillus rhamnosus) Lcr35^®. A high-throughput transcriptomic analysis revealed a specific response of C. elegans depending on whether it is in the presence of the LBM L. rhamnosus Lcr35^® (structural response), the yeast Candida albicans (metabolic response) or both (structural and metabolic responses) in a preventive and a curative conditions. Studies on C. elegans mutants demonstrated that the p38 MAPK (sek-1, skn-1) and the insulin-like (daf-2, daf-16) signaling pathways were involved in the extended lifespan provided by L. rhamnosus Lcr35^® strain whereas the JNK pathway was not involved (jnk-1). In addition, the anti C. albicans effect of the bacterium requires the daf-16 and sek-1 genes while it is independent of daf-2 and skn-1. Moreover, the anti-aging effect of Lcr35^®, linked to the extension of longevity, is not due to protection against oxidative stress (H₂O₂). Taken together, these results formally show the involvement of the p38 MAP kinase and insulin-like signaling pathways for the longevity extension and anti-Candida albicans properties of Lcr35^® with, however, differences in the genes involved. Overall, these findings provide new insight for understanding the mechanisms of action of a probiotic strain with antimicrobial potential.

Abstract 2003: Poor diet quality is associated with immune aging in survivors of pediatric acute lymphoblastic leukemia

Rationale and objectives: Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer. Despite a 90% five-year survival rate, survivors of childhood ALL often suffer from late effects, including cardiometabolic disorders. Contributing factors such as inflammation and oxidative stress, combined with drug treatments, can induce premature aging and cellular senescence with a significant impact on cardiometabolic disorders. Premature aging can lead to decreased thymic T-cell production, resulting in decreased circulation of T-cell receptor excision circles (TRECs). Because diet has been associated with cardiometabolic disorders, we hypothesized that the quality of diet in children who had survived ALL was related to the immune aging biomarker TREC, in concert with inflammatory status.

Methods: Adolescent and young adult survivors of pediatric ALL of the PETALE cohort (n=241, 22.1 ± 6.3 years at diagnosis, 49.4% male) were examined in their profile for TREC levels (by qPCR) and for adherence to 6 diet quality indices.

Results: Adjusted linear regressions revealed that the Healthy Diet Indicator (HDI) was associated with TREC levels (β=50.0, p=0.005, adjusted p=0.03). After performing a conceptual relational analysis (CAR) for data mining of various biomarkers of inflammation, oxidative stress, endotoxemia, and endothelial or adipose dysfunction; interleukin-6 (IL-6) and C-reactive protein (CRP) were found to be negatively associated with TREC levels (β= -80 and -80.1, p=0.017 and 0.026, respectively) but not with HDI. Further analysis revealed that IL-6 and CRP levels were moderators, but not mediators, of the association between HDI and TREC.

Conclusion: This study supports the positive impact of a healthy diet on premature immune aging and the moderating role of inflammation in this association.

Citation Format: Abderrahim Benmoussa, Tibila Kientega, Sophia Morel, Guillaume Cardin, Sophie Bérard, Mickael wajnberg, Petko Valtchev, Alexandre Blondin-Masse, Daniel Curnier, Maja Krajinovic, Caroline Laverdière, Daniel Sinnett, Emile Levy, Sophie Marcoux, Francis Rodier, Valérie Marcil. Poor diet quality is associated with immune aging in survivors of pediatric acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2003.

Development of an innovative methodology combining chemical fractionation and in vivo analysis to investigate the biological properties of cheese

With the ever-increasing human lifespan, age-related affections have become a public health issue. The health sector is looking for new bioactive compounds to respond to this demand. The unexplored microbial biodiversity and its metabolites represent a major source of innovative bioactive molecules with health potential. Fermented foods, such as raw-milk cheese, have already been investigated for their rich microbial environment, especially for their organoleptic qualities. But studies remain limited regarding their effects on health and few metabolites of microbial origin have been identified. An efficient methodology was developed in this study to investigate the biological effect of raw-milk cheese, combining a chemical fractionation, to isolate the most metabolites from the cheese matrix, and an in vivo biological test using Caenorhabditis elegans. C. elegans was brought into contact with cheese extracts, obtained by means of chemical fractionation, and with freeze-dried whole cheese by supplementing the nematode growth medium. A longevity assay was performed to evaluate the effects of the extracts on the worms. Our results demonstrate the feasibility of the method developed to bring the worms into contact of the cheese extracts. The evaluation of the effects of the extracts on the longevity was possible. Some extracts showed a beneficial effect as extract W70 for example, obtained with water, which increases the mean lifespan by 16% and extends the longevity by 73% (p < 0.0001).

Non-canonical ATM/MRN activities temporally define the senescence secretory program

Senescent cells display senescence-associated (SA) phenotypic programs such as stable proliferation arrest (SAPA) and a secretory phenotype (SASP). Senescence-inducing persistent DNA double-strand breaks (pDSBs) cause an immediate DNA damage response (DDR) and SAPA, but the SASP requires days to develop. Here, we show that following the immediate canonical DDR, a delayed chromatin accumulation of the ATM and MRN complexes coincides with the expression of SASP factors. Importantly, histone deacetylase inhibitors (HDACi) trigger SAPA and SASP in the absence of DNA damage. However, HDACi-induced SASP also requires ATM/MRN activities and causes their accumulation on chromatin, revealing a DNA damage-independent, non-canonical DDR activity that underlies SASP maturation. This non-canonical DDR is required for the recruitment of the transcription factor NF-κB on chromatin but not for its nuclear translocation. Non-canonical DDR further does not require ATM kinase activity, suggesting structural ATM functions. We propose that delayed chromatin recruitment of SASP modulators is the result of non-canonical DDR signaling that ensures SASP activation only in the context of senescence and not in response to transient DNA damage-induced proliferation arrest.

[Primary mesothelioma of the pericardium: diagnostic methods. A case report]

Clinical picture and diagnostic methods in a patient with primary pericardial mesothelioma are described. Echocardiography shows an intrapericardial mass in direct continuity with left ventricular wall. Magnetic resonance imaging is essential to define mass dimension and extension and show cardiac wall and contiguous tissues infiltration. The histological characteristics are defined by using TAC-guided needle biopsy and needle aspiration.

[An electro- and vectorcardiographic study of ventricular activation in scleroderma]

Electrical ventricular activation was studied by means of electrocardiogram and vectorcardiogram in 62 patients, 55 women and 7 men, affected by systemic sclerosis of average disease duration of 10.3 years. 45% of the patients showed the "diffused form" of the disease and 55% the "limited form". The vectorcardiogram showed some alterations of the ventricular activation in 55% of the recorded cases. The previous electrocardiogram found only 18%. The alterations, which are more frequent in the diffuse form than in the limited one, are the presence of loss of forces in septal, lateral or inferior or combined areas and intraventricular conduction disorders as complete and incomplete right bundle branch block, left anterior subdivision block, left posterior subdivision block, or combination between incomplete right bundle branch block and left anterior or posterior subdivision block. The vectorcardiogram was more sensitive than the electrocardiogram in showing loss of forces, also in patients with the limited form of systemic sclerosis, when the electrocardiogram was normal. Moreover the vectorcardiogram is helpful to identify left posterior subdivision block. The vectorcardiographic investigation seems to be a useful complement of the electrocardiogram especially for the identification of cases with myocardial involvement that is clinically silent.

[Acute hepatic ischemia and cardiogenic shock in patients with dilated cardiomyopathy]

A sharp and unusually high increase in the serum of glutamic-oxalacetic and glutamic-pyruvic transaminase and of lactic-dehydrogenase accompanied the terminal events, acute pulmonary edema with cardiogenic shock, in 2 patients suffering from chronic congestive heart failure caused by dilatative myocardiopathy. Experimental and clinical data raises the possibility that the considerable enzymic increase may be due to the combined effect of chronic stasis and acute ischemia on the liver.

[Electrocardiographic disorders in diverse clinical variations of scleroderma]

The electrocardiograms of 130 patients affected by scleroderma, 117 with systemic sclerosis (67 with diffuse and 50 with limited form) and 13 with localized scleroderma were analyzed. ECG was normal in 44.6% of cases, respectively in 39.3% with systemic sclerosis and in 92.3% with localized scleroderma. The more frequent electrocardiographic abnormalities were supraventricular and ventricular premature beats, right bundle branch block, left anterior hemiblock, low QRS voltages, ST-T wave abnormalities and Q or QS aspects. All the abnormalities above resulted to be more frequent in the patients with diffuse systemic sclerosis in comparison to the patients with limited systemic sclerosis. Our results confirm that the cardiac involvement appears to be much more serious in the diffuse systemic sclerosis.

[Pre- and postoperative ECG-VCG study of the correction of atrioventricular septal defects]

In order to determine the possible implication of the right bundle branch block (RBBB) in the superior axis deviation of patients (pt) affected with AV septal (Canal) defect, we studied the preoperative and postsurgical ECG of 50 patients who underwent radical correction of the malformation complex. 36 pt had the complete form and 14 a partial form. In 14 of them it was also possible to perform a VCG before and after surgery. The amplitude of S1, R' in a VR and V1 modified significantly (p less than 0.0001), the AQRS showed a clockwise displacement of 19 degrees (p less than 0.002). The terminal forces in the VCG frontal plane changed significantly 62 degrees (p less than 0.0001). Nevertheless the D.I. in a VL and V6 made no difference. Postoperative ECG patterns of pt with partial or complete forms did not differ substantially. Results allowed us to conclude that the major determinant of the AV septal defect ECG pattern is the posterior (inlet) deficiency of the interventricular septum. Surgical correction of the right ventricle overload leads to a clockwise AQRS displacement in the frontal plane. The conduction asynchronism through the left branch showed no modifications.

[Superior axial deviation in the young adult. An electro-vectorcardiographic study]

We analyzed the VCGs of 100 young subjects without apparent cardiac disease showing an ECG superior Axis Deviation, i.e. AQRS greater than - 30 degrees, and a rS aspect in V1. Our findings demonstrated that, in these subjects, the superior axis deviation is due to a distal right bundle branch block with posterior displacement of the terminal forces in 78% of the cases. The other cases being left anterior hemiblocks, either isolated (12%) or associated with a block of the anterior subdivision of the right bundle branch (10%). The differential diagnosis, easy on VCG, is sometimes very difficult on ECG. The most reliable ECG criteria to discriminate this kind of right bundle branch block from left anterior hemiblock are: intrinsic deflection in a VL-V6 greater than or equal to 0.015" (sensitivity 100%; specificity 57%), RV6/Ra VL ratio greater than 1 (sensibility 100%; specificity 50%) and the presence of a notched R wave in L2, L3 and a VF (sensitivity 90%; specificity 100%).

[Electro-vectorcardiographic behavior of right bundle branch block in endocardial cushion defects. Its probable relation to the so-called left anterior fascicular hemiblock]

We have investigated the possible ECG signs of incomplete Left Anterior Hemiblock (LAH). As an experimental model we chose the endocardial cushion defect, which is proved to have a ventricular activation correspondent to different degrees of LAH due to the particular disposition of the AV node and the His bundle. The VCG of 50 patients with endocardial cushion defect were divided into 5 groups according to the entity of the left and superior deviation of the maximum left vector. Comparison with the ECG signs shows that: a) minimal degrees of LAH occur with simple counterclockwise rotation of the frontal loop without a significant left axis deviation; b) there is no linear correlation between the importance of the left axis deviation and the signs of left ventricular activation asincronism. We conclude that, with the exception of this particular congenital heart disease, minimal LAH degrees can only be suspected on the basis of a counterclockwise VCG frontal loop, because the ECG diagnosis is possible only when the left axis deviation becomes important.