OBJECTIVE: To identify whether naringenin plays a protective role during thoracic aneurysm formation in Marfan syndrome. METHODS: To validate the effect of naringenin, Fbn1^C1039G/+ mice, the mouse model of Marfan syndrome, were fed with naringenin, and the disease progress was evaluated. The molecular mechanism of naringenin was further investigated via in vitro studies, such as bioluminescence resonance energy transfer (BRET), atomic force microscope and radioligand receptor binding assay. RESULTS: Six-week-old Fbn1^C1039G/+ mice were fed with naringenin for 20 weeks. Compared with the control group, naringenin significantly suppressed the aortic expansion [Fbn1^C1039G/+ vs. Fbn1^C1039G/++naringenin: (2.49±0.47) mm, n=18 vs. (1.87±0.19) mm, n=22, P < 0.05], the degradation of elastin, and the expression and activity of matrix metalloproteinase 2 (MMP2) and MMP9 in the ascending aorta of Fbn1^C1039G/+ mice. Besides, treatment with naringenin for 6 weeks also attenuated the disease progress among the 20-week-old Fbn1^C1039G/+ mice with established thoracic aortic aneurysms [Fbn1^C1039G/+ vs. Fbn1^C1039G/++naringenin: (2.24±0.23) mm, n=8 vs. (1.90±0.17) mm, n=8, P < 0.05]. To understand the underlying molecular mechanisms, we examined the effects of naringenin on angiotensin Ⅱ type 1 receptor (AT1) signaling and transforming growth factor-β (TGF-β) signaling respectively, which were the dominant signaling pathways contributing to aortopathy in Marfan syndrome as previously reported. The results showed that naringenin decreased angiotensin Ⅱ (Ang Ⅱ)-induced phosphorylation of protein kinase C (PKC) and extracellular regulating kinase 1/2 (ERK1/2) in HEK293A cell overexpressing AT1 receptor. Moreover, naringenin inhibited Ang Ⅱ-induced calcium mobilization and uclear factor of activated T-cells (NFAT) signaling. The internalization of AT1 receptor and its binding to β-arrestin-2 with Ang Ⅱ induction were also suppressed by naringenin. As evidenced by atomic force microscope and radioligand receptor binding assay, naringenin inhibited Ang Ⅱ binding to AT1 receptor. In terms of TGF-β signaling, we found that feeding the mice with naringenin decreased the phosphorylation of Smad2 and ERK1/2 as well as the expression of TGF-β downstream genes. Besides, the serum level of TGF-β was also decreased by naringenin in the Fbn1^C1039G/+ mice. Furthermore, we detected the effect of naringenin on platelet, a rich source of TGF-β, both in vivo and in vitro. And we found that naringenin markedly decreased the TGF-β level by inhibiting the activation of platelet. CONCLUSION Our study showed that naringenin has a protective effect on thoracic aortic aneurysm formation in Marfan syndrome by suppressing both AT1 and TGF-β signaling.
Angiotensin II/metabolism* ; Animals ; Aortic Aneurysm, Thoracic/prevention & control* ; Calcium/metabolism* ; Disease Models, Animal ; Elastin/metabolism* ; Fibrillin-1/metabolism* ; Flavanones ; Marfan Syndrome/metabolism* ; Matrix Metalloproteinase 2 ; Matrix Metalloproteinase 9 ; Mice ; Mice, Inbred C57BL ; Protein Kinase C/metabolism* ; Receptor, Angiotensin, Type 1/metabolism* ; Transforming Growth Factor beta/metabolism* ; Transforming Growth Factors/metabolism* ; beta-Arrestins/metabolism*

Angiotensin II Type 1 Receptor Blockers/adverse effects* ; Angiotensin-Converting Enzyme 2 ; Angiotensin-Converting Enzyme Inhibitors/adverse effects* ; Betacoronavirus ; COVID-19 ; Coronavirus Infections/etiology* ; Humans ; Pandemics ; Peptidyl-Dipeptidase A/physiology* ; Pneumonia, Viral/etiology* ; SARS-CoV-2

BACKGROUND: Dysregulation of hepatic glucose production (HGP) contributes to the development of type 2 diabetes mellitus. Telmisartan, an angiotensin II type 1 receptor blocker (ARB), has various ancillary effects in addition to common blood pressure-lowering effects. The effects and mechanism of telmisartan on HGP have not been fully elucidated and, therefore, we investigated these phenomena in hyperglycemic HepG2 cells and high-fat diet (HFD)-fed mice.METHODS: Glucose production and glucose uptake were measured in HepG2 cells. Expression levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase α (G6Pase-α), and phosphorylation levels of insulin receptor substrate-1 (IRS-1) and protein kinase C ζ (PKCζ) were assessed by western blot analysis. Animal studies were performed using HFD-fed mice.RESULTS: Telmisartan dose-dependently increased HGP, and PEPCK expression was minimally increased at a 40 μM concentration without a change in G6Pase-α expression. In contrast, telmisartan increased phosphorylation of IRS-1 at Ser302 (p-IRS-1-Ser302) and decreased p-IRS-1-Tyr632 dose-dependently. Telmisartan dose-dependently increased p-PKCζ-Thr410 which is known to reduce insulin action by inducing IRS-1 serine phosphorylation. Ectopic expression of dominant-negative PKCζ significantly attenuated telmisartan-induced HGP and p-IRS-1-Ser302 and -inhibited p-IRS-1-Tyr632. Among ARBs, including losartan and fimasartan, only telmisartan changed IRS-1 phosphorylation and pretreatment with GW9662, a specific and irreversible peroxisome proliferator-activated receptor γ (PPARγ) antagonist, did not alter this effect. Finally, in the livers from HFD-fed mice, telmisartan increased p-IRS-1-Ser302 and decreased p-IRS-1-Tyr632, which was accompanied by an increase in p-PKCζ-Thr410.CONCLUSION: These results suggest that telmisartan increases HGP by inducing p-PKCζ-Thr410 that increases p-IRS-1-Ser302 and decreases p-IRS-1-Tyr632 in a PPARγ-independent manner.
Animals ; Blotting, Western ; Diabetes Mellitus, Type 2 ; Diet, High-Fat ; Ectopic Gene Expression ; Glucose ; Glucose-6-Phosphatase ; Hep G2 Cells ; Insulin Receptor Substrate Proteins ; Insulin ; Liver ; Losartan ; Mice ; Peroxisomes ; Phosphoenolpyruvate ; Phosphorylation ; Protein Kinase C ; Protein Kinases ; Receptor, Angiotensin, Type 1 ; Receptor, Insulin ; Serine

BACKGROUND: Apart from its blood pressure-lowering effect by blocking the renin-angiotensin-aldosterone system, telmisartan, an angiotensin II type 1 receptor blocker (ARB), exhibits various ancillary effects including cardiovascular protective effects in vitro. Nonetheless, the protective effects of telmisartan in cerebrocardiovascular diseases are somewhat variable in large-scale clinical trials. Dysregulation of endothelial nitric oxide (NO) synthase (eNOS)-derived NO contributes to the developments of various vascular diseases. Nevertheless, the direct effects of telmisartan on endothelial functions including NO production and vessel relaxation, and its action mechanism have not been fully elucidated. Here, we investigated the mechanism by which telmisartan regulates NO production and vessel relaxation in vitro and in vivo. METHODS: We measured nitrite levels in culture medium and mouse serum, and performed inhibitor studies and western blot analyses using bovine aortic endothelial cells (BAECs) and a hyperglycemic mouse model. To assess vessel reactivity, we performed acetylcholine (ACh)-induced vessel relaxation assay on isolated rat aortas. RESULTS: Telmisartan decreased NO production in normoglycemic and hyperglycemic BAECs, which was accompanied by reduced phosphorylation of eNOS at Ser¹¹⁷⁹ (p-eNOS-Ser¹¹⁷⁹). Telmisartan increased the expression of protein phosphatase 2A catalytic subunit (PP2Ac) and co-treatment with okadaic acid completely restored telmisartan-inhibited NO production and p-eNOS-Ser¹¹⁷⁹ levels. Of the ARBs tested (including losartan and fimasartan), only telmisartan decreased NO production and p-eNOS-Ser¹¹⁷⁹ levels, and enhanced PP2Ac expression. Co-treatment with GW9662 had no effect on telmisartan-induced changes. In line with in vitro observations, telmisartan reduced serum nitrite and p-eNOS-Ser¹¹⁷⁹ levels, and increased PP2Ac expression in high fat diet-fed mice. Furthermore, telmisartan attenuated ACh-induced rat aorta relaxation. CONCLUSION: We demonstrated that telmisartan inhibited NO production and vessel relaxation at least in part by PP2A-mediated eNOS-Ser¹¹⁷⁹ dephosphorylation in a peroxisome proliferator-activated receptor γ-independent manner. These results may provide a mechanism that explains the inconsistent cerebrocardiovascular protective effects of telmisartan.
Acetylcholine ; Animals ; Aorta ; Blotting, Western ; Catalytic Domain ; Endothelial Cells ; In Vitro Techniques ; Losartan ; Mice ; Mice, Obese ; Nitric Oxide Synthase Type III ; Nitric Oxide ; Okadaic Acid ; Peroxisomes ; Phosphorylation ; Protein Phosphatase 2 ; Rats ; Receptor, Angiotensin, Type 1 ; Relaxation ; Renin-Angiotensin System ; Vascular Diseases

Angiotensin-(1-9) [Ang-(1-9)], generated from Ang I by Ang II converting enzyme 2, has been reported to have protective effects on cardiac and vascular remodeling. However, there is no report about the effect of Ang-(1-9) on pulmonary hypertension. The aim of the present study is to investigate whether Ang-(1-9) improves pulmonary vascular remodeling in monocrotaline (MCT)-induced pulmonary hypertensive rats. Sprague-Dawley rats received Ang-(1-9) (576 µg/kg/day) or saline via osmotic mini-pumps for 3 weeks. Three days after implantation of osmotic mini-pumps, 50 mg/kg MCT or vehicle were subcutaneously injected. MCT caused increases in right ventricular weight and systolic pressure, which were reduced by co-administration of Ang-(1-9). Ang-(1-9) also attenuated endothelial damage and medial hypertrophy of pulmonary arterioles as well as pulmonary fibrosis induced by MCT. The protective effects of Ang-(1-9) against pulmonary hypertension were inhibited by Ang type 2 receptor (AT₂R) blocker, but not by Mas receptor blocker. Additionally, the levels of LDH and inflammatory cytokines, such as TNF-α, MCP-1, IL-1β, and IL-6, in plasma were lower in Ang-(1-9) co-treated MCT group than in vehicle-treated MCT group. Changes in expressions of apoptosis-related proteins such as Bax, Bcl-2, Caspase-3 and -9 in the lung tissue of MCT rats were attenuated by the treatment with Ang-(1-9). These results indicate that Ang-(1-9) improves MCT-induced pulmonary hypertension by decreasing apoptosis and inflammatory reaction via AT₂R.
Angiotensins* ; Animals ; Apoptosis ; Arterioles ; Blood Pressure ; Caspase 3 ; Cytokines ; Hypertension* ; Hypertension, Pulmonary ; Hypertrophy ; Interleukin-6 ; Lung ; Monocrotaline ; Plasma ; Pulmonary Fibrosis ; Rats ; Rats, Sprague-Dawley ; Receptor, Angiotensin, Type 2 ; Vascular Remodeling

INTRODUCTION: This study aimed to determine the 5-year incidence of albuminuria among Asian persons with newly diagnosed type 2 diabetes mellitus (DM), and to identify the risk factors at diagnosis for progression to albuminuria. MATERIALS AND METHODS: A retrospective 5-year closed cohort study was conducted among 1016 persons aged ≥18 years old who were diagnosed with type 2 DM between 1 January 2007 and 31 December 2009 at primary care facilities in Singapore. The cumulative incidence of progression from normoalbuminuria to albuminuria-termed "progression"-was determined. The risk factors associated with progression were evaluated using multiple logistic regression analysis. RESULTS: A total of 541 (53.2%) participants were men. The mean (SD) onset age of type 2 DM was 54 (11) years. From diagnosis of type 2 DM, the 5-year cumulative incidence of progression was 17.3% and mean (SD) duration to progression was 2.88 (1.23) years. Higher onset age (OR 1.02; 95% CI, 1.00-1.04), history of hypertension (OR, 1.88; 95% CI, 1.32-2.70) and higher glycated haemoglobin (HbA1c) (OR, 1.17; 95% CI, 1.09-1.26) at diagnosis were associated with progression. In addition, being on angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) treatment at baseline modified the effect of hypertension on progression. CONCLUSION This study highlighted the importance of early screening and treatment of diabetes as well as prevention of hypertension, which could potentially delay the onset of microalbuminuria in persons with type 2 DM. Persons on ACEI or ARB treatment should continue to be monitored regularly for progression to albuminuria.
Adult ; Age of Onset ; Aged ; Albuminuria ; epidemiology ; Angiotensin Receptor Antagonists ; therapeutic use ; Angiotensin-Converting Enzyme Inhibitors ; therapeutic use ; Cohort Studies ; Diabetes Mellitus, Type 2 ; diagnosis ; epidemiology ; metabolism ; Disease Progression ; Female ; Glycated Hemoglobin A ; metabolism ; Humans ; Hypertension ; drug therapy ; epidemiology ; Logistic Models ; Male ; Middle Aged ; Retrospective Studies ; Risk Factors ; Singapore ; epidemiology

BACKGROUND: Extracellular sulfatases (Sulfs), sulfatase 1 (Sulf1) and sulfatase 2 (Sulf2), play a pivotal role in cell signaling by remodeling the 6-O-sulfation of heparan sulfate proteoglycans on the cell surface. The present study examined the effects of Sulfs on angiotensin II (Ang II)-induced hypertensive mediator expression and vascular smooth muscle cells (VSMCs) proliferation in spontaneously hypertensive rats (SHR). METHODS: Ang II receptors, 12-lipoxygenase (12-LO), and endothelin-1 (ET-1) messenger RNA (mRNA) expressions in SHR VSMCs were analyzed by real-time polymerase chain reaction and Western blotting. VSMCs proliferation was determined by [³ H]-thymidine incorporation. RESULTS: Basal Sulfs mRNAs expression and enzyme activity were elevated in SHR VSMCs. However, Sulfs had no effect on the basal or Ang II-induced 12-LO and ET-1 mRNA expression in SHR VSMCs. The inhibition of Ang II-induced 12-LO and ET-1 expression by blockade of the Ang II type 2 receptor (AT₂ R) pathway was not observed in Sulf1 siRNA-transfected SHR VSMCs. However, Sulf2 did not affect the action of AT₂ R inhibitor on Ang II-induced 12-LO and ET-1 expression in SHR VSMCs. The down-regulation of Sulf1 induced a reduction of AT₂ R mRNA expression in SHR VSMCs. In addition, the inhibition of Ang II-induced VSMCs proliferation by blockade of the AT₂ R pathway was mediated by Sulf1 in SHR VSMCs. CONCLUSION: These findings suggest that extracellular sulfatase Sulf1 plays a modulatory role in the AT₂ R pathway that leads to an Ang II-induced hypertensive effects in SHR VSMCs.
Angiotensin II* ; Angiotensins* ; Arachidonate 12-Lipoxygenase ; Blotting, Western ; Down-Regulation ; Endothelin-1 ; Heparan Sulfate Proteoglycans ; Hypertension ; Muscle, Smooth, Vascular* ; Rats, Inbred SHR* ; Real-Time Polymerase Chain Reaction ; Receptor, Angiotensin, Type 2* ; RNA, Messenger ; Sulfatases

This study was aimed to investigate the association of candidate gene polymorphisms and obesity or overweight in young Korean children. A total of 190 Korean preschool children (96 control, 48 overweight, and 46 obese children) were genotyped for the angiotensin converting enzyme (ACE) insertion (I)/deletion (D), angiotensin II type 2 receptor (AT2) C3123A, transforming growth factor (TGF)-β1 T869C, vascular endothelial growth factor (VEGF) T460C, and tumor necrosis factor (TNF)-α G308A polymorphisms. No differences were found among the groups with respect to age, sex, birth weight, blood pressure levels, and serum concentrations of glucose and total cholesterol. Obese children showed a higher incidence of ACE DD genotype and D allelic frequency compared to the controls (odds ratio [OR], 2.7, 95% confidence interval [CI], 1.01–7.21; OR, 2.5, 95% CI, 1.49–4.19; all P < 0.05). The frequency of TC genotype and C allele in the TGF-β1 T869C polymorphism (OR, 2.08, 95% CI, 1.01–4.27; OR, 1.93, 95% CI, 1.15–3.21) and that in the VEGF T460C polymorphism (OR, 2.5, 95% CI, 1.19–5.28; OR, 2.15, 95% CI, 1.26–3.68) was also higher in obese children than in control subjects (all P < 0.05). Overweight children exhibited a higher frequency of the A allele in the AT2 C3123A polymorphism compared to the controls (OR, 1.72, 95% CI, 1.03–2.88, P < 0.05). There were no differences in the TNF-α G308A polymorphism among the groups. The ACE I/D, AT2 C3123A, TGF-β1 T869C, and VEGF T460C polymorphisms can affect susceptibility to obesity or overweight in Korean children.
Alleles ; Angiogenic Proteins ; Birth Weight ; Blood Pressure ; Child ; Child, Preschool* ; Cholesterol ; Genetic Variation ; Genotype ; Glucose ; Humans ; Incidence ; Obesity ; Overweight ; Pediatric Obesity* ; Peptidyl-Dipeptidase A ; Receptor, Angiotensin, Type 2 ; Renin-Angiotensin System ; Transforming Growth Factors ; Tumor Necrosis Factor-alpha ; Vascular Endothelial Growth Factor A

BACKGROUND: Extracellular sulfatases (Sulfs), sulfatase 1 (Sulf1) and sulfatase 2 (Sulf2), play a pivotal role in cell signaling by remodeling the 6-O-sulfation of heparan sulfate proteoglycans on the cell surface. The present study examined the effects of Sulfs on angiotensin II (Ang II)-induced hypertensive mediator expression and vascular smooth muscle cells (VSMCs) proliferation in spontaneously hypertensive rats (SHR).METHODS: Ang II receptors, 12-lipoxygenase (12-LO), and endothelin-1 (ET-1) messenger RNA (mRNA) expressions in SHR VSMCs were analyzed by real-time polymerase chain reaction and Western blotting. VSMCs proliferation was determined by [³ H]-thymidine incorporation.RESULTS: Basal Sulfs mRNAs expression and enzyme activity were elevated in SHR VSMCs. However, Sulfs had no effect on the basal or Ang II-induced 12-LO and ET-1 mRNA expression in SHR VSMCs. The inhibition of Ang II-induced 12-LO and ET-1 expression by blockade of the Ang II type 2 receptor (AT₂ R) pathway was not observed in Sulf1 siRNA-transfected SHR VSMCs. However, Sulf2 did not affect the action of AT₂ R inhibitor on Ang II-induced 12-LO and ET-1 expression in SHR VSMCs. The down-regulation of Sulf1 induced a reduction of AT₂ R mRNA expression in SHR VSMCs. In addition, the inhibition of Ang II-induced VSMCs proliferation by blockade of the AT₂ R pathway was mediated by Sulf1 in SHR VSMCs.CONCLUSION: These findings suggest that extracellular sulfatase Sulf1 plays a modulatory role in the AT₂ R pathway that leads to an Ang II-induced hypertensive effects in SHR VSMCs.
Angiotensin II ; Angiotensins ; Arachidonate 12-Lipoxygenase ; Blotting, Western ; Down-Regulation ; Endothelin-1 ; Heparan Sulfate Proteoglycans ; Hypertension ; Muscle, Smooth, Vascular ; Rats, Inbred SHR ; Real-Time Polymerase Chain Reaction ; Receptor, Angiotensin, Type 2 ; RNA, Messenger ; Sulfatases

OBJECTIVETo examine the efficacy and safety of dual blockade of the renin-angiotensin-aldosterone system (RAAS) among patients with type 2 diabetic kidney disease.

DATA SOURCESWe searched the major literature repositories, including the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE, for randomized clinical trials published between January 1990 and October 2015 that compared the efficacy and safety of the use of dual blockade of the RAAS versus the use of monotherapy, without applying any language restrictions. Keywords for the searches included "diabetic nephropathy," "chronic kidney disease," "chronic renal insufficiency," "diabetes mellitus," "dual therapy," "combined therapy," "dual blockade," "renin-angiotensin system," "angiotensin-converting enzyme inhibitor," "angiotensin-receptor blocker," "aldosterone blockade," "selective aldosterone blockade," "renin inhibitor," "direct renin inhibitor," "mineralocorticoid receptor blocker," etc.

STUDY SELECTIONThe selected articles were carefully reviewed. We excluded randomized clinical trials in which the kidney damage of patients was related to diseases other than diabetes mellitus.

RESULTSCombination treatment with an angiotensin-converting enzyme inhibitor supplemented by an angiotensin II receptor blocking agent is expected to provide a more complete blockade of the RAAS and a better control of hypertension. However, existing literature has presented mixed results, in particular, related to patient safety. In view of this, we conducted a comprehensive literature review in order to explain the rationale for dual blockade of the RAAS, and to discuss the pros and cons.

CONCLUSIONSDespite the negative results of some recent large-scale studies, it may be immature to declare that the dual blockade is a failure because of the complex nature of the RAAS surrounding its diversified functions and utility. Further trials are warranted to study the combination therapy as an evidence-based practice.

Angiotensin Receptor Antagonists ; therapeutic use ; Angiotensin-Converting Enzyme Inhibitors ; therapeutic use ; Animals ; Antihypertensive Agents ; therapeutic use ; Diabetes Mellitus, Type 2 ; complications ; Diabetic Nephropathies ; drug therapy ; Humans ; Renin-Angiotensin System ; drug effects