Endoplasmic reticulum stress response in immune cells contributes to experimental autoimmune encephalomyelitis pathogenesis in rats

We examined the role of endoplasmic reticulum (ER) stress and the ensuing unfolded protein response (UPR) in the development of the central nervous system (CNS)-directed immune response in the rat model of experimental autoimmune encephalomyelitis (EAE). The induction of EAE with syngeneic spinal cord homogenate in complete Freund's adjuvant (CFA) caused a time-dependent increase in the expression of ER stress/UPR markers glucose-regulated protein 78 (GRP78), X-box-binding protein 1 (XBP1), C/EBP homologous protein (CHOP), and phosphorylated eukaryotic initiation factor 2α (eIF2α) in the draining lymph nodes of both EAE-susceptible Dark Agouti (DA) and EAE-resistant Albino Oxford (AO) rats. However, the increase in ER stress markers was more pronounced in AO rats. CFA alone also induced ER stress, but the effect was weaker and less sustained compared to full immunization. The ultrastructural analysis of DA lymph node tissue by electron microscopy revealed ER dilatation in lymphocytes, macrophages, and plasma cells, while immunoblot analysis of CD3-sorted lymph node cells demonstrated the increase in ER stress/UPR markers in both CD3+ (T cell) and CD3- (non-T) cell compartments. A positive correlation was observed between the levels of ER stress/UPR markers in the CNS-infiltrated mononuclear cells and the clinical activity of the disease. Finally, the reduction of EAE clinical signs by ER stress inhibitor ursodeoxycholic acid was associated with the decrease in the expression of mRNA encoding pro-inflammatory cytokines TNF and IL-1β, and encephalitogenic T cell cytokines IFN-γ and IL-17. Collectively, our data indicate that ER stress response in immune cells might be an important pathogenetic factor and a valid therapeutic target in the inflammatory damage of the CNS.

The presence of Mott cells in the lymph nodes of rats with experimental autoimmune encephalomyelitis

Mott cells are plasma cells that have multiple spherical Russell bodies packed in their cytoplasm. Russell bodies are dilated endoplasmic reticulum cisternae filled with aggregates of immunoglobulins that are neither secreted nor degraded. Mott cells were observed in our study by light and electron microscope in the lymph nodes of rats with experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Mott cells were detected on hematoxylin and eosin (HE)-stained lymph node sections as vacuolated cells with eccentrically positioned nuclei and large number of faint blue spherical inclusions in the cytoplasm. Electron microscopic investigation revealed the presence of Russell bodies of the "medusa" form inside Mott cells in lymph node ultra-thin sections of EAE animals. Mott cells expressed the plasma cell marker CD138 and either kappa or lambda immunoglobulin light chains, indicating their origin from polyclonally activated B cells. Finally, Mott cells were associated with active EAE, as they were not found in the lymph nodes of EAE-resistant Albino Oxford rats. The presence of Russell bodies implies an excessive production of immunoglobulins in EAE, thus further emphasizing the role of B cells, and among them Mott cells, in the pathogenesis of this animal model of multiple sclerosis.

Proapoptotic and proautophagy effect of H1-receptor antagonist desloratadine in human glioblastoma cell lines

Glioblastomas are aggressive and usually incurable high-grade gliomas without adequate treatment. In this study, we aimed to investigate the potential of desloratadine to induce apoptosis/autophagy as genetically regulated processes that can seal cancer cell fates. All experiments were performed on U251 human glioblastoma cell line and primary human glioblastoma cell culture. Cytotoxic effect of desloratadine was investigated using MTT and CV assays, while oxidative stress, apoptosis, and autophagy were detected by flow cytometry and immunoblot. Desloratadine treatment decreased cell viability of U251 human glioblastoma cell line and primary human glioblastoma cell culture (IC50 value 50 µM) by an increase of intracellular reactive oxygen species and caspase activity. Also, desloratadine decreased the expression of main autophagy repressor mTOR and its upstream activator Akt and increased the expression of AMPK. Desloratadine exerted dual cytotoxic effect inducing both apoptosis- and mTOR/AMPK-dependent cytotoxic autophagy in glioblastoma cells and primary glioblastoma cell culture.

The impact of interval vs. continuous training on troponin and natriuretic peptide levels in post-myocardial patients: a randomised control trial

Introduction

High-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) are two well established and used exercise modalities for cardiac rehabilitation in patients after myocardial infarction. However, data on their effects on clinically relevant biomarkers, e.g. troponin and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels are scarce. The aim of the study was to assess the acute and long-term effects of HIIT vs. MICT on troponin and NT-proBNP levels in patients after myocardial infarction.

Methods

Patients referred to cardiac rehabilitation after myocardial infarction were randomised to either HIIT or MICT. HIIT consisted of 7 cycles of 1.5 min of 80–90% VO2peak and 3 min of 65–70% VO2peak intensity; MICT consisted of 32 min of 75% VO2peak intensity. We have determined troponin and NT-proBNP levels before (resting), immediately after, and one hour after (a) the first and (b) the last exercise training session, in order to appraise the specific effects of HIIT vs. MICT on an acute and long-term response to training. Cardiopulmonary exercise testing was performed in all patients. Wilcoxon signed-rank test was used to compare two related samples.

Results

One hundred six patients were included (55±10 years of age, 20% females), 53 in each group. There were no differences between HIIT and MICT groups in baseline characteristics.

Both HIIT and MICT caused the release of NT-proBNP levels during the first exercise training session (from median 159 to 169 ng/L, p<0.001 for HIIT; from median 217 to 226 ng/L, p<0.001 for MICT), while only HIIT additionally lead to an elevation in NT-proBNP levels even 1 hour after the first session of the exercise training programme (from median 169 to 182 ng/L, p=0.002). After 36 sessions of the exercise training programme, this trend of a further increase in NT-proBNP levels was not present.

Neither HIIT nor MICT raised troponin levels during both the first and the last exercise training visit. After both types of exercise (during recovery), however, a decrease in troponin level was present and was significant, but only after the first training visit (from median 10.5 to 10.0 ng/L, p=0.014 for HIIT; from 13.1 to 12.4 ng/L, p=0.035 for MICT). Interestingly, MICT, but not HIIT, caused a significant increase in troponin levels after the termination of the last exercise training visit (from median 10.5 to 10.9 ng/L, p=0.004).

Conclusion

Both HIIT and MICT significantly cause an acute increase in NT-proBNP levels, while only HIIT is associated with further elevation of NT-proBNP levels after the termination of the first exercise training session in patients after myocardial infarction. On the contrary, neither exercise training modality causes a significant increase in troponin levels, suggesting that the safety pattern of both exercise training modalities may be comparable.

Funding Acknowledgement

Type of funding sources: None.

Adherence to the Mediterranean lifestyle in patients after myocardial infarction

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

ReKoBo study group

INTRODUCTION

Adherence to the Mediterranean diet is associated with decreased cardiovascular and overall mortality, and is recommended by the relevant preventive cardiology guidelines. However, besides specific dietary intake, Mediterranean lifestyle includes a series of eating habits and social behaviours. All these aspects are summed in the Medlife questionnaire.

PURPOSE

The aim of our study was to assess adherence to the Mediterranean lifestyle and examine associations with clinically relevant variables, in patients after myocardial infarction referred to cardiac rehabilitation.

METHODS

This was a single-centre cross-sectional study. Mediterranean lifestyle pattern was assessed using a validated Medlife questionnaire, which includes 28 questions (15 questions on the Mediterranean diet adherence, 6 questions on the eating habits and behaviour, and 7 questions on the social pattern of the Mediterranean lifestyle). Associations of the Medlife score with the exercise performance (assessed by the cardiopulmonary exercise testing), clinical data, demographics, lipid status, and quality of life (assessed by the HeartQol questionnaire) were assessed using Spearman’s correlation coefficient, while differences between two groups were determined with the independent-samples t-test.

RESULTS

There were 111 patients included in the study, mean age 55 +/- 10 years, 20% of them were women. Adherence to the Mediterranean lifestyle was not associated with age, BMI, peak VO2, total or LDL cholesterol. Also, there were no differences in terms of Medlife score between women vs. men, and between patients living in urban vs. rural areas. There were, however, significant associations between Medlife score and HDL (r = 0.239, p = 0.012), triglyceride level (r=-0.383, p < 0.001) and blood glucose level (r=-0.214, p = 0.024), and with the emotional aspects of the quality of life (r = 0.245, p = 0.017). Also, higher-educated were significantly more adherent to the Mediterranean lifestyle as compared to lower-educated patients (16.2 vs. 14.7 points, p = 0.018).

CONCLUSION

Poorer adherence to the Mediterranean lifestyle is associated with substandard control of lipid status and glucose level. Improvement in the Mediterranean lifestyle adherence might be a cornerstone in the cardiac rehabilitation beyond exercise training programmes.

The impact of interval vs. continuous training on exercise capacity and endothelial function in post-myocardial patients: a randomised control trial

Introduction

High-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) are two most common and well established exercise modalities for cardiac rehabilitation in patients after myocardial infarction. Yet, data on their effects on cardiovascular parameters beyond exercise capacity (e.g. endothelial function) are scarce.

Methods

Patients referred to cardiac rehabilitation (CR) after myocardial infarction were randomised to HIIT or MICT. HIIT consisted of 7 cycles of 1.5 min of 80–90% VO2peak and 3 min of 65–70% VO2peak intensity; MICT consisted of 32 min of 75% VO2peak intensity. We ultrasonographically appraised flow-mediated dilation (FMD) – a marker of endothelial function – before (resting), immediately after and one hour after (a) the first and (b) the last exercise training session, in order to appraise the specific effects of HIIT vs. MICT on acute and long-term vascular response to training. Cardiopulmonary exercise testing was performed in all patients. We compared the effects of training modalities with ANCOVA using baseline values as covariates, and examined the improvement after CR in each intervention group with paired-samples t-test.

Results

Eighty-six patients were included (55±10 years of age, 19% females), 43 in each group. There were no differences between HIIT and MICT groups in baseline characteristics. VO2peak improved in both groups (HIIT: 22.8 to 24.9 ml/kg/min, p=0.016 and MICT: 21.9 to 24.5 ml/kg/min, p<0.001), with no significant between-group differences (p=0.571). Also, resting FMD improved after both HIIT and MICT (4.6 to 6.7%, p=0.016, and 4.7 to 8.0%, p=0.001, respectively), with no significant between-group differences (p=0.177). Acute vascular response to training, however, improved with HIIT (FMD one hour after the last training session: 4.1 to 7.1%, p=0.022), but not MICT (5.9 to 6.4%, p=0.584).

Conclusion

Both HIIT and MICT significantly and comparably improve exercise capacity and resting FMD in patients after myocardial infarction. In addition, however, HIIT is associated with improved vascular response during recovery period after exercise.

Funding Acknowledgement

Type of funding source: None

Role of AMPK/mTOR-independent autophagy in clear cell renal cell carcinoma

We examined the status and role of autophagy, a process of lysosomal recycling of cellular material, in clear cell renal cell carcinoma (ccRCC). Paired samples of tumor and adjacent non-malignant tissue were collected from 20 patients with ccRCC after radical nephrectomy. The mRNA levels of apoptosis (BAD, BAX, BCL2, BCLXL, BIM) and autophagy (ATG4, BECN1, GABARAP, p62, UVRAG) regulators were measured by RT-qPCR. The protein levels of autophagosome-associated LC3-II, autophagy receptor p62, apoptotic marker PARP, as well as phosphorylation of autophagy initiator Unc 51-like kinase 1 (ULK1), its activator AMP-activated protein kinase (AMPK) and 4EBP1, the substrate of ULK1 inhibitor mechanistic target of rapamycin (mTOR), were analyzed by immunoblotting. The mRNA levels of pro-apoptotic BAX, anti-apoptotic BCLXL and pro-autophagic ATG4, p62 and UVRAG were higher in ccRCC tumors. Autophagy induction was confirmed by an increase in phospho-ULK1 and degradation of the autophagic target p62, while apoptotic PARP cleavage was unaltered. AMPK phosphorylation was reduced and 4EBP1 phosphorylation was increased in ccRCC tissue. The expression of apoptosis regulators did not correlate with clinicopathological features of ccRCC. Conversely, high mRNA levels of ATG4, GABARAP and p62 were associated with lower tumor stage, as well as with smaller tumor size and better disease-specific 5-year survival (ATG4 and p62). Accordingly, low p62 protein levels, corresponding to increased autophagic flux, were associated with lower tumor stage, reduced metastasis and improved 5-year survival. These data demonstrate that transcriptional induction of autophagy in ccRCC is accompanied by AMPK/mTOR-independent increase in ULK1 activation and autophagic flux, which might slow tumor progression and metastasis independently of apoptosis.

Influence of preoperative statins and aspirin administration on biological and magnetic resonance imaging properties in patients with abdominal aortic aneurysm

Background: Main objective of this study was to evaluate the influence of statins and/or acetylsalicylic acid on biochemical characteristics of abdominal aortic aneurysm (AAA) wall and intraluminal thrombus (ILT). Patients and methods: Fifty patients with asymptomatic infrarenal AAA were analyzed using magnetic resonance imaging on T1w sequence. Relative ILT signal intensity (SI) was determined as a ratio between ILT and psoas muscle SI. Samples containing the full ILT thickness and aneurysm wall were harvested from the anterior surface at the level of the maximal diameter. The concentration of enzymes such as matrix metalloproteinase (MMP) 9, MMP2 and neutrophil elastase (NE/ELA) were analyzed in ILT and AAA wall; while collagen type III, elastin and proteoglycan 4 were analyzed in harvested AAA wall. Oxidative stress in the AAA wall was assessed by catalase and malondialdehyde activity in tissue samples. Results: Relative ILT signal intensity (1.09 ± 0.41 vs 0.89 ± 0.21, p = 0.013) were higher in non-statin than in statin group. Patients who were taking aspirin had lower relative ILT area (0.89 ± 0.19 vs 1.13. ± 0.44, p = 0.016), and lower relative ILT signal intensity (0.85 [0.73-1.07] vs 1.01 [0.84-1.19], p = 0.021) compared to non-aspirin group. There were higher concentrations of elastin in AAA wall among patients taking both of aspirin and statins (1.21 [0.77-3.02] vs 0.78 (0.49-1.05) ng/ml, p = 0.044) than in patients who did not take both of these drugs. Conclusions: Relative ILT SI was lower in patients taking statin and aspirin. Combination of antiplatelet therapy and statins was associated with higher elastin concentrations in AAA wall.

6076Improvement of exercise capacity over the course of outpatient cardiac rehabilitation is an independent predictor of prognosis after a myocardial infarction

Background

Cardiac rehabilitation after myocardial infarction improves cardiovascular health and quality of life. However, data on long-term prognostic impact of surrogate rehabilitation parameters–such as exercise capacity improvements–remain scarce.

Purpose

To assess the independent prognostic impact of exercise capacity improvement over the course of outpatient cardiac rehabilitation after myocardial infarction.

Methods

Consecutive patients undergoing outpatient cardiac rehabilitation (3-times weekly for 12 weeks) after a myocardial infarction at a university centre were included. Exercise testing was performed at inclusion and after completion of the rehabilitation programme, with exercise capacity improvement defined as ≥2 MET increase over the course of the programme. Clinical data and risk factors were systematically collected, and patients were followed up for a minimum of 2 years. Kaplan-Meier curves and a multivariate Cox proportional hazard model were constructed for prediction of events (defined as a composite of incident cardiovascular death, re-infarction and coronary revascularsiation), with age, sex, LDL-cholesterol levels and body mass index as co-variates.

Results

A total of 409 patients were included (20% women). Exercise capacity and expected exercise performance were significantly improved after cardiac rehabilitation programme (6.6 to 9.5 METs, p<0.001, and 82 to 117%, p<0.001, respectively). After a median follow-up of 6.5 years, 93 patients experienced an event. Exercise capacity improvement of ≥2 METs was associated with reduced event rates (Figure 1), retaining statistical significance even after adjusting for age, sex, LDL-cholesterol and body mass index (HR 0.485, 95% CI 0.285–0.824).

Kaplan-Meier curve

Conclusion

Improvement of exercise performance over the course of outpatient cardiac rehabilitation is an independent predictor of prognosis after a myocardial infarction, with improvements of ≥2 METs associated with a 50% reduction in events.

Identification of a functional protein kinase Cbeta promoter polymorphism in humans related to insulin resistance

Protein kinase Cbeta (PKCbeta) is known to inhibit insulin production in beta-cells and to support insulin action in skeletal muscle. We therefore searched for functional polymorphisms among already known genetic variants in the PKCbeta promoter and investigated their relation to glucose metabolism in humans. We found that the gene variant in the PKCbeta promoter at position -546 significantly reduced promoter activity in functional assays (P<0.05). Human subjects carrying this variant had a 3.5-fold decrease in PKCbeta2-protein expression in their thrombocytes (P=0.006). Additionally, we tested whether this variant affects parameters of glucose metabolism using 1012 humans included into the MeSyBePo study (Metabolic Syndrome Berlin Potsdam). The -546 variant was highly significant associated with increased homeostasis model assessment for insulin resistance (HOMA-IR, P=0.009) in the cohort. This association was accompanied by significantly increased fasting insulin concentrations in carriers of the homozygous polymorphism (P=0.021). Our results suggest that the -546 polymorphism in the PKCbeta promoter reduces promoter activity, which leads to a decreased expression of PKCbeta2 and subsequently is associated with decreased peripheral insulin-dependent glucose uptake.

HPLC determination of tiazofurin in the rat brain

A sensitive, selective and reproducible HPLC method for determination of tiazofurin in rat brain was developed and validated. The method allowed determination and quantification of nanomolar concentrations of tiazofurin in brain and its regions (hippocampus, cortex and striatum) of treated animals. Separation of tiazofurin from other peaks from brain tissue was achieved by isocratic elution on reverse phase chromatographic column. The mobile phase consisted of 0.05 M sodium acetate pH 4.6. Run time was 15 min.

Simultaneous LC determination of tiazofurin, its acetyl and benzoyl esters and their active metabolite thiazole-4-carboxamide adenine dinucleotide in biological samples

A rapid and sensitive HPLC-RP method for simultaneous determination of tiazofurin, its 5'-O acetyl and benzoyl esters and their active metabolite thiazole-4-carboxamide adenine dinucleotide was developed and validated. The method allowed determination and quantification of nanomolar quantities of these substances in cell extracts of treated cells, and was also used in kinetic studies of cellular uptake of tiazofurin and its esters from the cultivation medium. Separation of the analyzed substances from unidentified peaks from both biological materials was achieved by gradient elution, thus reducing the possibility of interference. The mobile phase consisted of a 0.1 M sodium-hydrogen phosphate, pH 5.1 and methanol. Run time was 22 min, with 5 min equilibration time.