Gene Expression Of Renin-angiotensin System Components Research Articles

The angiotensin II type 1 receptor blocker valsartan in the battle against COVID‐19

ObjectiveSevere acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2) uses the host’s angiotensin‐converting enzyme 2 (ACE2) as a cellular entry point. Therefore, modulating ACE2 might impact SARS‐CoV‐2 viral replication, shedding, and coronavirus disease 2019 (COVID‐19) severity. Here, it was investigated whether the angiotensin II type 1 receptor blocker valsartan alters the expression of renin‐angiotensin system (RAS) components, including ACE2, in human adipose tissue (AT) and skeletal muscle.MethodsA randomized, double‐blind, placebo‐controlled clinical trial was performed, in which 36 participants (BMI 31.0 ± 0.8 kg/m2) with impaired glucose metabolism received either valsartan or placebo for 26 weeks. Before and after 26 weeks’ treatment, abdominal subcutaneous AT and skeletal muscle biopsies were obtained, and gene expression of RAS components was measured by quantitative reverse transcription polymerase chain reaction.ResultsValsartan treatment did not significantly impact the expression of RAS components, including ACE2, in AT and skeletal muscle.ConclusionsGiven the pivotal role of ACE2 in SARS‐CoV‐2 spread and the clinical outcomes in COVID‐19 patients, the data suggest that the putative beneficial effects of angiotensin II type 1 receptor blockers on the clinical outcomes of patients with COVID‐19 may not be mediated through altered ACE2 expression in abdominal subcutaneous AT.

Influence of Obesity in the Development of Chronic Kidney Disease: Contribution of Leptin and Angiotensin II in Inflammatory Processes

IntroductionObesity is associated with leptin resistance, as well as hyperactivity of the renin‐angiotensin system (RAS). Angiotensin II (Ang II) is an important pro‐inflammatory and pro‐fibrotic agent and is associated with the progression of chronic kidney disease (CKD). Therefore, the aim of this study is to investigate the contribution of Ang II and leptin in the development of CKD associated with obesity.MethodsThe protocols are in agreement with CEUA (nº 13/2017). Twenty‐four mice aged 18 weeks were used: Six C57BL / 6J were assigned to the lean control group (CTL) and 18 ob/ob were randomly assigned to obese control group (ob ob) and obese treated with leptin group (ob ob ‐ lep). Treatment with leptin was done by osmotic mini‐pump insertion. Mini‐pumps were filled with a solution containing leptin at a dose of 3.5 μg/day for 42 days. During treatment period animals were kept in individual cages and food intake was monitored daily. Weight gain and blood glucose were monitored weekly. At the end of the treatment period, animals were kept in metabolic cages for 24 hours to evaluate water intake and urine collection. Ultimately, animals were submitted to euthanasia. Renal function was assessed by plasma creatinine and urea concentration. Renal tissue was used for evaluation of gene expression by qPCR. Statistical analysis was performed by one‐way ANOVA, followed by Bonferroni post‐test. Values of p <0.05 were considered statistically significant.ResultsOb ob ‐lep animals had a reduction in food intake when compared to the ob ob group. Food intake in ob ob – lep was similar to CTL group. In ob ob ‐ lep animals there was also a reduction in body weight compared to ob ob. There were no changes in water intake, urine flow and blood glucose among groups. There were also no changes in plasma creatinine values among groups, however, in the ob ob group there was an increase in serum urea and the leptin treatment partially reversed this parameter to values closer to CTL group. Regarding gene expression of RAS components, ob ob animals showed an increase in mRNA expression for angiotensinogen compared to CTL group and leptin treatment did not reverse this parameter. The expression of mRNA for renin is also increased in the ob ob group, however, leptin treatment reversed this increase to values similar to control. Inflammation in obese animals was confirmed by increased IL6 mRNA expression and leptin did not reverse this parameter. There was no significant difference in mRNA expression for MCP1 among groups, however, there was a tendency to an increase in the expression of this gene in obese animals and decrease in leptin treatment. Obesity increased nephrine and αSMA mRNA expression compared to CTL, and leptin reversed this increase. Obesity increased the mRNA expression for collagen I and leptin did not reverse this parameter.ConclusionLeptin treatment was efficient because it decreased food intake and weight gain in obese animals. Obesity impairs renal function, increases the activation of intra‐renal RAS, inflammation and fibrosis, and leptin therapy partially reverses these parameters, taking renoprotective role.Support or Funding InformationCNPq, CAPES and FAPESP.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Basic Science Liver

Basic Science Liver

Effects of ACE2 deficiency on physical performance and physiological adaptations of cardiac and skeletal muscle to exercise.

The renin-angiotensin system (RAS) is related to physiological adaptations induced by exercise. Angiotensin-converting enzyme (ACE) 2 is a major regulator of the RAS in tissues, as it metabolizes angiotensin (Ang) II to Ang-(1-7). The aim of this study was to determine the effects of ACE2 deficiency on physical performance and physiological adaptations induced by voluntary running. Physical performance, body composition and plasma angiotensin levels, as well as tissue morphology and gene expression of RAS components in the left ventricle (LV) and skeletal muscle (gastrocnemius), were evaluated in ACE2-deficient (ACE2(-/y)) and wild-type (ACE2(+/y)) mice after 6 weeks of voluntary wheel running. ACE2(-/y) mice run less than ACE2(+/y) mice (19±4.7 vs. 26±12.6 revolutions per day × 100, P<0.01). The ACE2(+/y) group presented a lower fat mass (15±1.1%) and higher muscle mass (76.6±1.6%) after 6 weeks of voluntary running compared with the sedentary control group (fat mass: 18.3±2.1%; muscle mass: 72.7±2.2). However, no change in body composition was observed in ACE2(-/y) mice after exercise. Heart and skeletal muscle hypertrophy was observed only in trained ACE2(+/y) mice. Besides a small decrease in Ang I in ACE2(-/y) mice, plasma levels of angiotensin peptides remained unchanged by exercise or ACE2 deficiency. In the LV of trained animals, AT2 gene expression was higher in ACE2(+/y) compared with ACE2(-/y) mice. ACE2 deficiency leads to an increase in AT1 gene expression in skeletal muscle. ACE expression in soleus was increased in all exercised groups. ACE2 deficiency affects physical performance and impairs cardiac and skeletal muscle adaptations to exercise.

Long-Term Effects of Maternal Diabetes on Blood Pressure and Renal Function in Rat Male Offspring

Aims/HypothesisGestational diabetes mellitus (GDM) is increasing rapidly worldwide. Previous animal models were established to study consequences of offspring after exposure to severe intrauterine hyperglycemia. In this study we are aiming to characterize the blood pressure levels and renal function of male offspring obtained from diabetic mothers with moderate hyperglycemia.MethodsWe established a rat model with moderate hyperglycemia after pregnancy by a single intraperitoneal injection of streptozotocin (STZ). The male offspring were studied and fed with either normal diet or high salt diet after weaning. Arterial pressure and renal function were measured.ResultsArterial pressure of male offspring increased from 12 weeks by exposure to intrauterine moderate hyperglycemia. At 20 weeks, high salt diet accelerated the blood pressure on diabetic offspring compared to diabetic offspring fed with normal diet. We found offspring exposed to intrauterine moderate hyperglycemia had a trend to have a higher creatinine clearance rate and significant increase of urinary N-acetyl-β-D-glucosaminidase (NAG) excretion indicating an early stage of nephropathy progression.Conclusions/InterpretationWe observed the high blood pressure level and early renal dysfunction of male offspring obtained from diabetic mothers with moderate hyperglycemia. Furthermore, we investigated high salt diet after weaning on offspring exposed to intrauterine hyperglycemia could exacerbate the blood pressure and renal function. Renin angiotensin system (RAS) plays an important role in hypertension pathogenesis and altered gene expression of RAS components in offspring with in utero hyperglycemia exposure may account for the programmed hypertension. Therefore, our study provides evidence “fetal programming” of maternal diabetes is critical for metabolic disease development.

Aberrant Activation of the Intrarenal Renin-Angiotensin System in the Developing Kidneys of Type 2 Diabetic Rats

We have previously reported that intrarenal angiotensin II (Ang II) levels are increased long before diabetes becomes apparent in obese Otsuka-Long-Evans-Tokushima-Fatty (OLETF) rats, a model of type 2 diabetes. In this study, we examined the changes in intrarenal renin-angiotensin system (RAS) activity in the developing kidneys of OLETF rats. Ang II contents and mRNA levels of RAS components were measured in male OLETF and control Long-Evans Tokushima (LETO) rats at postnatal days (PND) 1, 5, and 15, and at 4-30 weeks of age. In both LETO and OLETF rats, kidney Ang II levels peaked at PND 1, then decreased during the pre- and post-weaning periods. However, Ang II levels and gene expression of RAS components, including angiotensinogen (AGT), renin, and angiotensin-converting enzyme (ACE), were not significantly different between LETO and OLETF rats. Intrarenal Ang IIcontents further decreased during puberty (from 7 to 11 weeks of age) in LETO rats, bur not in OLETF rats. At 11 weeks of age, kidney Ang II levels, urinary AGT excretion, and mRNA levels of AGT and renin were higher in OLETF rats than in LETO rats, while blood glucose levels were not significantly different between these groups of rats. These data indicate that continued intrarenal expression of Ang II during pubescence contributes to the increases in intrarenal Ang II levels in prediabetic OLETF rats, and is associated with increased intrarenal AGT and renin expression. Inappropriate activation of the intrarenal RAS in the prediabetic stage may facilitate the onset and development of diabetic nephropathy in later life.

Demonstration of renin mRNA, angiotensinogen mRNA, and angiotensin converting enzyme mRNA expression in the human eye: evidence for an intraocular renin-angiotensin system.

All components necessary for the formation of angiotensin II, the biologically active product of the renin-angiotensin system (RAS), have been demonstrated in ocular tissue or vitreous and subretinal fluid. The tissue concentrations of renin were too high to be explained by admixture of blood. This raises the possibility of an intraocular RAS, independent of the RAS in the circulation. In the present study, gene expression of RAS components in different parts of enucleated human eyes was investigated as evidence for tissue specific production. By using pooled tissue samples renin mRNA could be detected with the RNAse protection assay in retinal pigment epithelium (RPE) choroid, but not in neural retina or sclera. With reverse transcription polymerase chain reaction (RT-PCR), renin mRNA was detected in individual samples of RPE choroid and neural retina, and not anterior uveal tract or sclera. Angiotensinogen and angiotensin converting enzyme (ACE) gene expression could be demonstrated by RT-PCR in individual RPE choroid and neural retina samples and marginally in sclera samples. These results support the concept of intraocular synthesis of angiotensin II, independent of renin, angiotensin, and ACE in the circulation. Since gene expression was highest in ocular parts, which are highly vascularised, local angiotensin II may be involved in blood supply and/or pathological vascular processes such as neovascularisation in diabetic retinopathy.