Effect of caloric restriction on liver function in young and old ApoE/LDLr-/- mice

Background. Caloric restriction (CR) leads to decrease metabolic intensity, which results in a reduction of oxygen consumption and the amount of free radicals. This can affect the function of the liver. Studies show that caloric restriction does not alter or significantly increase the enzyme activity associated with gluconeogenesis, but the effect was different according to the age of the model animals. Objective. The aim of the study was to determine the effect of caloric restriction on liver function in young and old ApoE/ LDLr-/- mice. Material and methods. Dietary experiments were performed on 2 and 5 month old male ApoE/LDLr-/- mice. Animals were divided into 3 experimental groups (n=6) and fed AIN’93G diet for 8 and 5 weeks, respectively. Control animals were fed ad libitum (AL) and housed in a colony cages. These animals were checked for dietary intake. The second group were also fed ad libitum but the animals were kept individually in cages (stress AL- sAL). Similarly to sAL group, the animals from the CR group were kept individually but received a 30% less diet compared to AL group. At the end of the experiment animals were euthanized and the blood, liver and adipose tissue have been collected. Alanine aminotransferase (ALT) as well as aspartate aminotransferase (AST) were measured in plasma. Fatty acid profile was evaluated (relative %) in adipose tissue (GC-MS). Liver’s stetosis was assessed. Results were analyzed statistically (ANOVA, STATISTICA v.10.0). Results. CR ApoE/LDLr-/- mice showed significantly lower body weight compared to animals, both AL and sAL. There were no significant differences between ALT and AST in both younger and older animals. However, negative tendencies were more pronounced in younger animals. In young animals CR significantly increased liver weight compared to AL (4.14 vs 3.73g/100g). In adipose tissue fatty acid profile differed in CR mice compared to control in young animals. Conclusions. Caloric restriction did not affect liver enzymes in mice. Caloric restriction showed similar but not identical metabolic activity in young and old mice.Wprowadzenie. Restrykcje kaloryczne (CR) prowadzą do spadku intensywności metabolizmu, co wiąże się ze zmniejszeniem zużycia tlenu i ilości powstających wolnych rodników. Tym samym mogą mieć wpływ na funkcjonowanie wątroby. Badania wykazują, że ograniczenia kaloryczne nie zmieniają lub znacząco zwiększają aktywność enzymów związanych z glukoneogenezą, w tym kluczowego enzymu jakim jest aminotransferaza alaninowa (ALT). Obserwowany efekt był różny w zależności od wieku modelowych zwierząt. Cel badań. Celem pracy było określenie wpływu restrykcji kalorycznej na czynność wątroby u młodych i starszych myszy ApoE/LDLr-/-. Materiał i metody. Doświadczenie żywieniowe przeprowadzono na 2. i 5. miesięcznych samcach myszy ApoE/LDLr-/-. Zwierzęta podzielono na 3 grupy doświadczalne (n=6) i żywiono dietą AIN’93G przez okres 8 i 5. tygodni. Zwierzęta z grupy kontrolnej (AL) żywione były ad libitum i przetrzymywane zbiorowo w klatkach. Spożycie diety było sprawdzane. Grupa druga otrzymywała dietę ad libitum przy czym zwierzęta przetrzymywano w klatkach indywidualnie (sAL). Analogicznie do grupy drugiej zwierzęta z grupy restrykcji kalorycznych (CR) były trzymane indywidualnie, jednak otrzymywały 30% mniej diety w porównaniu do grupy kontrolnej AL. Po zakończeniu doświadczenia zwierzęta poddano eutanazji i pobrano wątrobę w celu oceny histologicznej (barwienie H&E i ORO) oraz krew, w której metodą spektrofotometryczną przeprowadzono oznaczenie enzymów aminotransferazy alaninowej (ALT), jak również aminotransferazy asparaginowej (AST). W tkance tłuszczowej oznaczono profil kwasów tłuszczowych (GC-MS). Wyniki poddano analizie statystycznej (ANOVA , STATISTICA v.10.0). Wyniki. Zarówno młodsze, jak i starsze myszy ApoE/LDLr-/- poddane restrykcji kalorycznej wykazały istotnie niższą końcową masę ciała w porównaniu do zwierząt z grup kontrolnych, zarówno AL, jak i sAL. Nie stwierdzono istotnych statystycznie różnic pomiędzy grupami w poziomie ALT, jak również AST zarówno u zwierząt młodszych, jak i starszych, przy czym negatywne tendencje były wyraźniej widoczne u zwierząt młodszych poddanych restrykcji kalorycznej. Również u młodszych zwierząt CR miało istotny niekorzystny wpływ na masę wątroby w porównaniu do kontroli (4,14 vs 3,73 g/100g). Zaobserwowano istotny wpływ CR na profil kwasów tłuszczowych w tkance tłuszczowej u zwierząt młodszych. Wnioski. Restrykcje kaloryczne nie miały wpływu na próby czynnościowe wątroby u myszy. Restrykcje kaloryczne wykazały podobną, ale nie identyczną aktywność metaboliczną u młodszych i starszych zwierząt

Distinct chemical changes in abdominal but not in thoracic aorta upon atherosclerosis studied using fiber optic Raman spectroscopy

Fiber optic Raman spectroscopy and Raman microscopy were used to investigate alterations in the aorta wall and the surrounding perivascular adipose tissue (PVAT) in the murine model of atherosclerosis (Apoe-/-/Ldlr-/- mice). Both abdominal and thoracic parts of the aorta were studied to account for the heterogenic chemical composition of aorta and its localization-dependent response in progression of atherosclerosis. The average Raman spectra obtained for both parts of aorta cross sections revealed that the chemical composition of intima-media layers along aorta remains relatively homogeneous while the lipid content in the adventitia layer markedly increases with decreasing distance to PVAT. Moreover, our results demonstrate that the increase of the lipid to protein ratio in the aorta wall correlates directly with the increased unsaturation level of lipids in PVAT and these changes occur only in the abdominal, but not in thoracic, aorta. In summary, distinct pathophysiological response in the aortic vascular wall could be uncovered by fiber optic Raman spectroscopy based on simple parameters detecting chemical contents of lipids in PVAT

Multi-omic signatures of atherogenic dyslipidaemia : pre-clinical target identification and validation in humans

Dyslipidaemia is a major risk factor for atherosclerosis and cardiovascular diseases. The molecular mechanisms that translate dyslipidaemia into atherogenesis and reliable markers of its progression are yet to be fully elucidated. To address this issue, we conducted a comprehensive metabolomic and proteomic analysis in an experimental model of dyslipidaemia and in patients with familial hypercholesterolemia (FH)

Chemical composition of atherosclerotic plaques of apoE/LDLR-double knockout mice by synchrotron radiation FTIR microspectroscopy

Atherosclerosis is a multietiological inflammatory disease of large and medium-sized arteries of increasing incidence in westernized countries. The aim of this study was to identify the biochemical changes during the progression of atherosclerosis by synchrotron radiation Fourier transform infrared microspectroscopy in atheromas of apoE/$LDLR^{-//-}$ mice fed egg-rich diet supplemented or not with angiotensin converting enzyme inhibitor perindopril. Synchrotron radiation Fourier transform infrared microspectroscopy technique was used to obtain information at high spatial resolution about the distribution of proteins (C-N, N-H, CO for amide I and amide II bands), lipids ($CH_2$, $CH_3$ bands) as well as mineral deposits (calcium carbonates and phosphates). Total contents of lipids and proteins were found to be significantly lower in animals treated with the diet and perindopril. An increase in saturation level of lipids was observed in animals fed with egg-rich diet when compared to the normal diet and perindopril treatment, which did not inhibit this effect. Moreover, a significant change in the secondary structure of proteins (ratio between absorption bands 1634 $cm^{-1}$/1656 $cm^{-1}$ attributed to β-type and α-type, respectively) was observed in both experimental groups in comparison with the control. Principal component analysis was used to analyse the recorded spectra. It has revealed that higher content of phosphates (wavenumber range 950-1020 $cm^{-1}$) was observed between egg-rich diet fed animals and the control group

Sex-specific differences of adenosine triphosphate levels in red blood cells isolated from ApoE/LDLR double-deficient mice

In this study for the first time, we investigated the correlation between sex-specific differences in adenosine triphosphate (ATP) levels in red blood cells (RBCs) and their mechanical, biochemical, and morphological alterations during the progression of atherosclerosis in ApoE/LDLR double-deficient ($ApoE/LDLR^{-/-}$) mice. Our results indicate that both sex and age affect alterations in RBCs of both $ApoE/LDLR^{-/-}$ and C57BL/6J mice. When compared with male RBCs, female RBCs were characterized by lower basal ATP and mean corpuscular hemoglobin concentration (MCHC), higher hemoglobin concentration (HGB), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), deformability, and phosphatidylserine (PS) exposure levels, regardless of age in both, $ApoE/LDLR^{-/-}$ and C57BL/6J mice. $ApoE/LDLR^{-/-}$ mice compared with age-matched controls showed lower basal ATP levels regardless of age and sex. Intracellular ATP level of RBCs was decreased solely in senescent female C57BL/6J mice, while it was elevated in males. Basal extracellular ATP levels were 400 times lower than corresponding intracellular level. In conclusion, basal ATP levels, RBC morphology, deformability, PS exposure levels alterations are sex-dependent in mice. Changes in basal ATP levels were correlated with PS exposure and trends of changes in MCV. Trends of changes of the most RBC parameters were similar in both sexes of $ApoE/LDLR^{-/-}$ mice compared with age-matched controls, however, their kinetics and levels vary greatly between different stages of disease progression

Effects of Low Carbohydrate High Protein (LCHP) diet on atherosclerotic plaque phenotype in ApoE/LDLR−/−ApoE/LDLR^{-/-} mice : FT-IR and Raman imaging

Low Carbohydrate High Protein (LCHP) diet displays pro-atherogenic effects, however, the exact mechanisms involved are still unclear. Here, with the use of vibrational imaging, such as Fourier transform infrared (FT-IR) and Raman (RS) spectroscopies, we characterize biochemical content of plaques in Brachiocephalic Arteries (BCA) from ApoE/LDLR−/− mice fed LCHP diet as compared to control, recomended by American Institute of Nutrition, AIN diet. FT-IR images were taken from 6–10 sections of BCA from each mice and were complemented with RS measurements with higher spatial resolution of chosen areas of plaque sections. In aortic plaques from LCHP fed ApoE/LDLR−/− mice, the content of cholesterol and cholesterol esters was increased, while that of proteins was decreased as evidenced by global FT-IR analysis. High resolution imaging by RS identified necrotic core/foam cells, lipids (including cholesterol crystals), calcium mineralization and fibrous cap. The decreased relative thickness of the outer fibrous cap and the presence of buried caps were prominent features of the plaques in ApoE/LDLR−/− mice fed LCHP diet. In conclusion, FT-IR and Raman-based imaging provided a complementary insight into the biochemical composition of the plaque suggesting that LCHP diet increased plaque cholesterol and cholesterol esters contents of atherosclerotic plaque, supporting the cholesterol-driven pathogenesis of LCHP–induced atherogenesis

Exercise capacity and cardiac hemodynamic response in female ApoE/LDLR^{-/-} mice : a paradox of preserved V'O_{2max} and exercise capacity despite coronary atherosclerosis

We assessed exercise performance, coronary blood flow and cardiac reserve of female ApoE/LDLR-/- mice with advanced atherosclerosis compared with age-matched, wild-type C57BL6/J mice. Exercise capacity was assessed as whole body maximal oxygen consumption (V'O2max), maximum running velocity (vmax) and maximum distance (DISTmax) during treadmill exercise. Cardiac systolic and diastolic function in basal conditions and in response to dobutamine (mimicking exercise-induced cardiac stress) were assessed by Magnetic Resonance Imaging (MRI) in vivo. Function of coronary circulation was assessed in isolated perfused hearts. In female ApoE/LDLR-/- mice V'O2max, vmax and DISTmax were not impaired as compared with C57BL6/J mice. Cardiac function at rest and systolic and diastolic cardiac reserve were also preserved in female ApoE/LDLR-/- mice as evidenced by preserved fractional area change and similar fall in systolic and end diastolic area after dobutamine. Moreover, endothelium-dependent responses of coronary circulation induced by bradykinin (Bk) and acetylcholine (ACh) were preserved, while endothelium-independent responses induced by NO-donors were augmented in female ApoE/LDLR-/- mice. Basal COX-2-dependent production of 6-keto-PGF1α was increased. Concluding, we suggest that robust compensatory mechanisms in coronary circulation involving PGI2- and NO-pathways may efficiently counterbalance coronary atherosclerosis-induced impairment in V'O2max and exercise capacity

HHIPL1, a Gene at the 14q32 Coronary Artery Disease Locus, Positively Regulates Hedgehog Signaling and Promotes Atherosclerosis

The research leading to these results has received funding from the European Union Seventh Framework Programme FP7/2007–2013 under grant agreement number HEALTH-F2-2013–601456, a Transatlantic Networks of Excellence Award (12CVD02) from The Leducq Foundation and the British Heart Foundation (SP/18/8/33620) as a partner of the European Research Area Network on Cardiovascular Diseases (ERA-CVD) druggable-MI-genes (01KL1802) and supported by the UK National Institute for Health Research (NIHR) Leicester Biomedical Research Centre. Dr Samani is a UK NIHR Senior Investigator. Drs Morris, Ye, and Webb are funded by the British Heart Foundation (SP/16/4/32697).Peer reviewedPublisher PD

Zatajanie rzeczywistości poprzez zakłócanie wspomnień i samooszukiwanie się: stawianie czoła błędom przeszłości w Pokucie Iana McEwana i Okruchach dnia Kazuo Ishiguro

W powyższej pracy omawiam problematykę narracji, która pozornie służyć ma jako medium samousprawiedliwienia za błędy popełnione w przeszłości człowieka. Na przykładach powieści Iana McEwana Pokuta oraz Kazuo Ishiguro Okruchy dnia stwierdzam jednak, że w rzeczywistości powieściopisarstwo, pod natłokiem niewygodnej przeszłości, a przede wszystkim poprzez zakłócanie i przeinaczanie swoich własnych wspomnień, staje się historią pełną półprawd. Wyżej wymienione pozycje omawiać będę w kategoriach powieści postmodernistycznej, analizując różnorakie literackie i retoryczne zabiegi (takie jak niewiarygodny narrator), które z powodzeniem zostały zastosowane przez obydwóch pisarzy. W pracy stwierdzam, że w następstwie tego typu narracji uwaga czytelnika skupia się na źródłach niewiarygodności oraz tych elementach historii, które celowo zostały ukryte przed oceną i postrzeganiem odbiorcy. Dlatego też moja uwaga poświęcona będzie omówieniu wyżej wymienionym zabiegom i temu, czy mają one wpływ na powieściopisarstwo i końcowy odbiór pozycji literackich, a jeżeli tak, to w jakim stopniu. Ponieważ niewiarygodność zakorzeniona jest w błędnych, a niekiedy celowo przeobrażanych wspomnieniach, część pierwszego rozdziału zostanie poświęcona pamięci w kontekście naukowym, a mianowicie dziedzinie nauki, która w ostatnim stuleciu w znaczącym stopniu się rozwinęła. Aspekty poruszone w pierwszym rozdziale staną się więc teoretycznym podłożem dla późniejszej analizy wspomnianych pozycji, którym poświęcony jest drugi oraz trzeci rozdział.This paper’s intention is to discuss two instances in which narratives are treated as an apparent medium for self-justification but — in fact — become a falsified reality due to the distortion of memories. I discuss Ian McEwan’s Atonement and Kazuo Ishiguro’s The Remains of the Day; the two novels which try to equate imagination and reality by creating narratives which intertwine those parts of the plot that are real and those that are fictional. I read those novels as postmodern and thereby discuss literary and rhetorical devices — as unreliability of narrations — successfully employed by McEwan and Ishiguro in their respective novels. What becomes an aftermath of those kinds of narratives is drawing readers’ attention to the sources of unreliabilities and those elements of the plot that are purposefully excluded from readers’ perception. My aim is therefore to discuss the sources of unreliability and the ways in which they influence storytelling in both novels. Owing to the fact that impartiality of narratives has its roots in memory issues I will also discuss memory studies that have blossomed since the beginning of the twentieth century. All of those aspects which are discussed in the first chapter provide theoretical foundation for further analysis of the already mentioned novels that are studied in the second and third chapters