Angiotensin-(1-7) receptor Mas deficiency does not exacerbate cardiac atrophy following high-level spinal cord injury in mice

Experimental spinal cord injury (SCI) causes a morphological and functional deterioration of the heart, in which the renin–angiotensin system (RAS) might play a role. The recently discovered non-canonical axis of RAS with angiotensin-(1-7) and its receptor Mas, which is associated with cardioprotection could be essential to prevent damage to the heart following SCI. We investigated the cardiac consequences of SCI and the role of Mas in female wild-type (WT, n = 22) and mice deficient of Mas (Mas(-/-), n = 25) which underwent spinal cord transection at thoracic level T4 (T4-Tx) or sham-operation by echocardiography (0, 7, 21, and 28 days post-SCI), histology and gene expression analysis at 1 or 2 months post-SCI. We found left ventricular mass reduction with preserved ejection fraction (EF) and fractional shortening in WT as well as Mas(-/-) mice. Cardiac output was reduced in Mas(-/-) mice, whereas stroke volume (SV) was reduced in WT T4-Tx mice. Echocardiographic indices did not differ between the genotypes. Smaller heart weight (HW) and smaller cardiomyocyte diameter at 1 month post-SCI compared to sham mice was independent of genotype. The muscle-specific E3 ubiquitin ligases Atrogin-1/MAFbx and MuRF1 were upregulated or showed a trend for upregulation in WT mice at 2 months post-SCI, respectively. Angiotensinogen gene expression was upregulated at 1 month post-SCI and angiotensin II receptor type 2 downregulated at 2 month post-SCI in Mas(-/-) mice. Mas was downregulated post-SCI. Cardiac atrophy following SCI, not exacerbated by lack of Mas, is a physiological reaction as there were no signs of cardiac pathology and dysfunction

The absence of serotonin in the brain alters acute stress responsiveness by interfering with the genomic function of the glucocorticoid receptors

Alterations in serotonergic transmission have been related to a major predisposition to develop psychiatric pathologies, such as depression. We took advantage of tryptophan hydroxylase (TPH) 2 deficient rats, characterized by a complete absence of serotonin in the brain, to evaluate whether a vulnerable genotype may influence the reaction to an acute stressor. In this context, we investigated if the glucocorticoid receptor (GR) genomic pathway activation was altered by the lack of serotonin in the central nervous system. Moreover, we analyzed the transcription pattern of the clock genes that can be affected by acute stressors. Adult wild type (TPH2(+/+)) and TPH2-deficient (TPH2(-/-)) male rats were sacrificed after exposure to one single session of acute restraint stress. Protein and gene expression analyses were conducted in the prefrontal cortex (PFC). The acute stress enhanced the translocation of GRs in the nucleus of TPH2(+/+) animals. This effect was blunted in TPH2(-/-) rats, suggesting an impairment of the GR genomic mechanism. This alteration was mirrored in the expression of GR-responsive genes: acute stress led to the up-regulation of GR-target gene expression in TPH2(+/+), but not in TPH2(-/-) animals. Finally, clock genes were differently modulated in the two genotypes after the acute restraint stress. Overall our findings suggest that the absence of serotonin within the brain interferes with the ability of the HPA axis to correctly modulate the response to acute stress, by altering the nuclear mechanisms of the GR and modulation of clock genes expression

Angiotensin‐II receptor type Ia does not contribute to cardiac atrophy following high‐thoracic spinal cord injury in mice

NEW FINDINGS: What is the central question of this study? Spinal cord injury leads to cardiac atrophy and the role of the renin-angiotensin system with angiotensin II acting via its receptor AT1a in this effect has not been previously explored. What is the main finding and its importance? In mice undergone thoracic level 4 transection, we confirm cardiac atrophy. Knockout of AT1a does not protect mice from cardiac atrophy. We observed no histopathological signs but reduced load-dependent left ventricular function (lower stroke volume and cardiac output) with preserved ejection fraction. Further investigations are warranted to assess cardiac function under stress conditions. ABSTRACT: Spinal cord injury (SCI) leads to cardiac atrophy often accompanied by functional deficits. The renin-angiotensin system (RAS) with angiotensin II (AngII) signalling via its receptor AT1a might contribute to cardiac atrophy post-SCI. We performed spinal cord transection at thoracic level T4 (T4-Tx) or sham-operation in female wild type mice (WT, n = 27) and mice deficient of AT1a (Agtr1a(-/-), n = 27). Echocardiography (0, 7, 21 and 28 days post-SCI) as well as histology and gene expression analyses at 1 and 2 months post-SCI were performed. We found cardiac atrophy post-SCI: reduced heart weight, estimated left ventricular mass in Agtr1a(-/-), and cardiomyocyte diameter in WT mice. Although, the latter as well as stroke volume (SV) and cardiac output (CO) were reduced in Agtr1a(-/-) mice already at baseline, cardiomyocyte diameter was even smaller in injured Agtr1a(-/-) mice compared to injured WT mice. SV and CO were reduced in WT mice post-SCI. Ejection fraction and fractional shortening was preserved post-SCI in both genotypes. There were no histological signs of fibrosis and pathology in the cardiac sections of both genotypes post-SCI. Gene expression of Agtr1a showed a trend for upregulation at 2 months post-SCI, angiotensinogen was upregulated at 2 month post-SCI in both genotypes. AngII receptor type 2 (Agtr2) was up-and down-regulated at 1 and 2 months post-SCI in WT mice, respectively, and Ang-(1-7) receptor (Mas) at 1 and 2 months post-SCI. Atrogin-1/MAFbx and MuRF1, the atrophy markers were not significantly upregulated post-SCI. Our data shows that lack of AT1a does not protect from cardiac atrophy post-SCI

Depletion of angiotensin-converting enzyme 2 reduces brain serotonin and impairs the running-induced neurogenic response

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordPhysical exercise induces cell proliferation in the adult hippocampus in rodents. Serotonin (5-HT) and angiotensin (Ang) II are important mediators of the pro-mitotic effect of physical activity. Here, we examine precursor cells in the adult brain of mice lacking angiotensin-converting enzyme (ACE) 2, and explore the effect of an acute running stimulus on neurogenesis. ACE2 metabolizes Ang II to Ang-(1-7) and is essential for the intestinal uptake of tryptophan (Trp), the 5-HT precursor. In ACE2-deficient mice, we observed a decrease in brain 5-HT levels and no increase in the number of BrdU-positive cells following exercise. Targeting the Ang II/AT1 axis by blocking the receptor, or experimentally increasing Trp/5-HT levels in the brain of ACE2-deficient mice, did not rescue the running-induced effect. Furthermore, mice lacking the Ang-(1-7) receptor, Mas, presented a normal neurogenic response to exercise. Our results identify ACE2 as a novel factor required for exercise-dependent modulation of adult neurogenesis and essential for 5-HT metabolism

Прогностическая роль уровня цитокинов амниотической жидкости плода и крови матери в вероятности развития гестационной гипертензии

Pregnancy induced hypertension, which includes both gestational hypertension (GH) and preeclampsia, is the most common medical disorder and remains one of the major causes of maternal and fetal death. The pathogenesis of GH is still unknown, yet immunologic and inflammatory causes may play an important role in the pathophysiology of this disease. The purpose of this study is to investigate the midtrimester IL-6, IL-8, IL-10, IL-12, TNF-α, SDF-1a and VEGF in the amniotic fluid (AF) and maternal blood regarding the above as being predictive for the gestational hypertension outcome. In the group of 128 pregnant women over 35 years old the six ones have developed GH. Our study results demonstrate that GH is associated with a strong increase of IL-6, IL-12 in maternal blood and a significant decrease of serum IL-10. Although AF level of both IL-6 and IL-10 has been significantly lower in GH subjects. In conclusion this study shows the relationship between the midtrimester IL-6, IL-12 and IL-10 concentrations in AF and maternal serum and GH outcome.Артериальная гипертензия при беременности, включающая в себя гестационную гипертензию и преэклампсию, является наиболее частым из осложнений беременности и остаётся одной из основных причин материнской смертности и гибели плода. Патогенез гестационной гипертензии до сих пор полностью не изучен, однако иммунологические и воспалительные факторы могут играть важную роль в патофизиологии этого заболевания. Целью данного исследования является изучение в период второго триместра беременности соотношения концентраций IL-6, IL-8, IL-10, IL-12, TNF-α, SDF-1a и VEGF в амниотической жидкости плода и материнской сыворотке крови и их связь с последующим развитием гестационной гипертензии. В группе из 128 беременных в возрасте старше 35 лет, в шести случаях выявлено развитие гестационной гипертензии. Полученные результаты определили, что наличие гестационной гипертензии связано с существенным увеличением концентрации сывороточного IL-6 и IL-12 и одновременным снижением IL-10 в крови матери, при том, что в амниотической жидкости выявлено существенное снижение как IL-10, так и IL-6. В заключении данное исследование доказывает связь между уровнями IL-6, IL-10 и IL-12 в амниотической жидкости плода и крови матери, выявленными во втором триместре беременности, и последующим развитием гестационной гипертензии

Genetic deletion of ACE2 induces vascular dysfunction in C57BL/6 mice: role of nitric oxide imbalance and oxidative stress

Accumulating evidence indicates that angiotensin-converting enzyme 2 (ACE2) plays a critical role in cardiovascular homeostasis, and its altered expression is associated with major cardiac and vascular disorders. The aim of this study was to evaluate the regulation of vascular function and assess the vascular redox balance in ACE2-deficient (ACE2-/y) animals. Experiments were performed in 20-22 week-old C57BL/6 and ACE2-/y male mice. Evaluation of endothelium-dependent and -independent relaxation revealed an impairment of in vitro and in vivo vascular function in ACE2-/y mice. Drastic reduction in eNOS expression at both protein and mRNA levels, and a decrease in •NO concentrations were observed in aortas of ACE2-/y mice in comparison to controls. Consistently, these mice presented a lower plasma and urine nitrite concentration, confirming reduced •NO availability in ACE2-deficient animals. Lipid peroxidation was significantly increased and superoxide dismutase activity was decreased in aorta homogenates of ACE2-/y mice, indicating impaired antioxidant capacity. Taken together, our data indicate, that ACE2 regulates vascular function by modulating nitric oxide release and oxidative stress. In conclusion, we elucidate mechanisms by which ACE2 is involved in the maintenance of vascular homeostasis. Furthermore, these findings provide insights into the role of the renin-angiotensin system in both vascular and systemic redox balance

Inflammation mitigation improves post-infarction functional recovery of the heart

Aim The in vitro evaluation of the cardiac functional effects of TNF-α antagonist administration in rats after isoproterenol induced myocardial infarction. Material and methods Myocardial infarction was reproduced using a proven model based on isoproterenol i/p administration in rats in 2 consecutive days in a similar dose, 150 mg/kg. In another group the animals after isoproterenol induced myocardial infarction (series IMI) have received daily TNF-α antagonist, a specific monoclonal antibody (ma-TNF-α) i/p in dose of 50 mg/kg during 8 days (series IMI+ma-TNF-α). In both series the animals were sacrificed after 10 days from the 1st injection and their isolated hearts ware perfused with Krebs solution according to Langendorff and Neely-Rovetto models. Results The most remarkable traits of left ventricle dysfunction in IMI in comparison to control were following: (1) diminution of cardiac output (CO), systolic pressure (SP) and +dP/dT max by respectively 28,7 and 34,7 and 23,3%; (2) negative inotropic effect to action of endothelin-1 manifested by decrease of SP and aortic jet during stimulation up to 13,9%; (3) increased cardiac arrhythmogenic activity in response to calcium overload; (4) increasing by 45,2% of ischemia induced contracture as well as decreasing by 37,5% of SP during reperfusion. The ma-TNF-α administration in post-infarction period led to noticeable benefits such as: significant enhancement of SP and CO respectively by 17,3 and 18,6% as well as positive inotropic effect developing to ET-1 action as well as significant increase of time regarding the appearance of ventricular extrasystole and ventricular tachyarrhythmia by respectively 12,9 and 11,7% as well as perceptible improvement of ischemia-reperfusion syndrome. Conclusion A sustained inflammation inhibition by ma-TNF-α administration in post-infarction period improves tangibly the cardiac functioning that proves the role of inflammatory response in myocardial infarction induced functional and structural myocardial remodeling and underlines the inflammation as a therapeutic target

Normothermic mouse functional MRI of acute focal thermostimulation for probing nociception

Combining mouse genomics and functional magnetic resonance imaging (fMRI) provides a promising tool to unravel the molecular mechanisms of chronic pain. Probing murine nociception via the blood oxygenation level-dependent (BOLD) effect is still challenging due to methodological constraints. Here we report on the reproducible application of acute noxious heat stimuli to examine the feasibility and limitations of functional brain mapping for central pain processing in mice. Recent technical and procedural advances were applied for enhanced BOLD signal detection and a tight control of physiological parameters. The latter includes the development of a novel mouse cradle designed to maintain whole-body normothermia in anesthetized mice during fMRI in a way that reflects the thermal status of awake, resting mice. Applying mild noxious heat stimuli to wildtype mice resulted in highly significant BOLD patterns in anatomical brain structures forming the pain matrix, which comprise temporal signal intensity changes of up to 6% magnitude. We also observed sub-threshold correlation patterns in large areas of the brain, as well as alterations in mean arterial blood pressure (MABP) in response to the applied stimulus

Neurolysin knockout mice generation and initial phenotype characterization

The oligopeptidase neurolysin (EC 3.4.24.16; Nln) was first identified in rat brain synaptic membranes and shown to ubiquitously participate in the catabolism of bioactive peptides such as neurotensin and bradykinin. Recently, it was suggested that Nln reduction could improve insulin sensitivity. Here, we have shown that Nln knockout mice (KO) have increased glucose tolerance, insulin sensitivity and gluconeogenesis. KO mice have increased liver mRNA for several genes related to gluconeogenesis. Isotopic label semi-quantitative peptidomic analysis suggests increase in specific intracellular peptides in gastrocnemius and epididymal adipose tissue, which likely is involved with the increased glucose tolerance and insulin sensitivity in the KO mice. These results suggest the exciting new possibility that Nln is a key enzyme for energy metabolism and could be a novel therapeutic target to improve glucose uptake and insulin sensitivity