Endothelial dysfunction: how can one intervene at the beginning of the cardiovascular continuum?

Raman spectroscopy reveals collagen and phospholipids as major components of hyalinosis in the arteriolosclerotic ulcer of Martorell

BACKGROUND

Arteriolosclerotic ulcers of Martorell are histologically characterized by hyaline arteriolosclerosis resulting in concentric occlusion of the arteriolar lumina. Although several authors have previously reported on hyaline changes in hypertensive arteriolopathies, so far, little information is available on the molecular composition of hyaline wall depositions.

OBJECTIVES

This study aimed at the molecular characterization of hyaline arteriolar deposits in patients with hypertensive arteriolopathy using confocal Raman spectroscopy.

METHODS

Samples of patients diagnosed with arteriolosclerotic ulcers of Martorell were analysed using confocal Raman spectroscopy. The findings were correlated with histological analyses. Skin samples from healthy, non-hypertensive patients served as controls.

RESULTS

Confocal Raman spectroscopy analysis revealed that subendothelial hyaline deposits in arteriolosclerotic ulcers are mainly composed of collagen and phospholipids, in particular phosphatidylcholine. The presence of collagen within hyaline deposits was confirmed by Masson's Trichrome and Picrosirius Red staining. Additionally, the presence of collagen could also be shown for hypertensive nephrosclerosis. Actin was markedly decreased in hyalinized compared to control vessels, corresponding to the loss of smooth muscle cells in the process of hyalinization. This was confirmed by immunofluorescence staining for α-smooth muscle actin and desmin.

CONCLUSION

The present findings suggest that arteriolar hyaline deposits in hypertensive arteriolopathy are mainly composed of collagen and phospholipids, in particular phosphatidylcholine. Together with the concurrent absence of actin, these findings suggest that potentially critical disease mechanisms involve pressure-induced vascular smooth muscle cell apoptosis with subsequent deposition of collagen.

[Association of CMTM5 gene expression with the risk of in-stent restenosis in patients with coronary artery disease after drug-eluting stent implantation and the effects and mechanisms of CMTM5 on human vascular endothelial cells]

OBJECTIVE

To elucidate the correlation between CKLF-like marvel transmembrane domain containing member (CMTM5) gene and the risk of in-stent restenosis (ISR) with coronary artery disease (CAD) patients and to detect the effects and mechanisms of CMTM5-stimulated genes on human vascular endothelial cells (ECs) proliferation and migration.

METHODS

A total of 124 hospitalized patients in Shijitan Hospital were enrolled in this study. All the CAD patients were detected with platelet reactivity and grouped into two groups according to platelet reactivity; ISR was conformed by coronary angiography; RT-PCR method was used to detect CMTM5 gene expression; The CMTM5 over expression, reduction and control EC lines were established; Cell count, MTT, Brdu and flow cytometry methods were used to detect the proliferation of ECs, scratch and transwell experiments to test the migration of ECs, Western blot was used to detect signal path expressions.

RESULTS

CMTM5 gene expression in HAPR (High on aspirin platelet reactivity) group was 1.72 times compared with No-HAPR group, which was significantly higher than No-HAPR group. HAPR group ISR rate was 25.8% (8 cases), the incidence of No-HAPR ISR group was 9.7% (9 cases), and the results showed that in HAPR group, the incidence of ISR was significantly higher than that in No-HAPR group (P=0.04, OR=0.04, 95%CI=1.16－7.52), which showed that CMTM5 gene was significantly correlated with the risk of ISR. In HAPR group ISR rate was 25.8% (8 cases), the incidence of ISR in No-HAPR group was 9.7% (9 cases), and the results showed that the risk of ISR in HAPR group was significantly higher than that in No-HAPR group. All the results showed that CMTM5 was significantly correlated with the risk of ISR in CAD patients (P < 0.05). CMTM5 overexpression inhibited the proliferation and migration ability of ECs (P < 0.05), PI3K/Akt signaling pathways were involved in the role of regulation on ECs.

CONCLUSION

Our results revealed that CMTM5 gene was closely related with ISR, CMTM5 overexpression may repress ECs proliferation and migration through regulating PI3K-Akt signaling.

Effect of Renin-Angiotensin System Blockade on Mortality in Korean Hypertensive Patients with Proteinuria

Background

Although renin-angiotensin system (RAS) blockade is recommended for hypertensive patients with proteinuria, the effect of RAS blockade on Korean hypertensive patients has not been investigated.

Methods

Among individuals who underwent a National Health Examination between 2002 and 2003 in Korea, hypertensive patients with proteinuria (defined as a dipstick test result ≥2+) were enrolled in this study. We investigated the outcomes of two groups stratified by RAS blockade prescription (with RAS blockade vs. without RAS blockade). Moreover, Cox proportional hazard regression and Kaplan-Meier analyses were performed to examine the effects of RAS blockade on mortality and end-stage renal disease (ESRD).

Results

A total of 8,460 patients were enrolled in this study, of whom 6,236 (73.7%) were prescribed with RAS blockade. The mean follow-up period was 129 months. A total of 1,003 (11.9%) patients died, of whom 273 (3.2%) died of cardiovascular (CV) events. The Kaplan-Meier curves for all-cause or CV mortality showed that the survival probability was significantly higher in the RAS blockade group than in the non-RAS blockade group. Multivariate Cox analysis also revealed RAS blockade significantly reduced the all-cause and CV mortality rates by 39.1% and 33.7%, respectively, compared with non-RAS blockade, even after adjusting for age, sex, and comorbid diseases; however, ESRD was not affected.

Conclusion

In this study, we found that RAS blockade was significantly associated with a reduction in mortality but not in the incidence of ESRD. However, 26.3% of the enrolled patients did not use RAS blockade. Physicians need to consider the usefulness of RAS blockade in hypertensive patients with proteinuria.

Studies to Elucidate the Effects of Furostanol Glycosides from Dioscorea deltoidea Cell Culture in a Rat Model of Endothelial Dysfunction

Currently, there is no doubt surrounding a theory that the cardiotropic effects of sex hormones can be due to their direct effect on the cardiovascular system. In recent years, interest in the study of steroid glycosides has increased. We studied the effects of furostanol glycosides (protodioscin and deltozid) from the cell culture of the Dioscorea deltoidea (laboratory code DM-05) on the physiological and biochemical parameters of vascular endothelial function in hypoestrogen-induced endothelial dysfunction after bilateral ovariectomy. It was shown that the use of DM-05 at a dose of 1 mg/kg makes it possible to prevent the development of arterial hypertension (the level of systolic blood pressure (SBP) decreases by 9.7% (p < 0.05) and diastolic blood pressure (DBP) by 8.2%), to achieve a decrease in the coefficient of endothelial dysfunction by 1.75 times against the background of a hypoestrogenic state. With DM-05, an increase in the concentration of stable nitric oxide metabolites (NOx) by 45.6% (p < 0.05) and an increase in mRNA endothelial nitric oxide synthase (eNOS) expression by 34.8% (p < 0.05) was established, which indicates a positive effect of furostanol glycosides on the metabolism of nitric oxide after ovariectomy. Positive dynamics in the histological structure of the heart and the abdominal aorta indicate the pronounced endothelio- and atheroprotective effects of DM-05.

Topical Application of Culture-Expanded CD34+ Umbilical Cord Blood Cells from Frozen Units Accelerates Healing of Diabetic Skin Wounds in Mice

Chronic and nonhealing wounds are constant health issues facing patients with type 2 diabetes. As the incidence of type 2 diabetes mellitus (T2DM) increases, the incidence of chronic wounds and amputations will rise. T2DM is associated with peripheral arterial occlusive disease, which leads to the development of nonhealing skin ulcers after minor trauma. Patients develop severe pain limiting their mobility and ability to work and take care of themselves, thus putting a significant burden on the family and society. CD34+ cells from umbilical cord blood (UCB) grown in fibroblast growth factor-4 (FGF-4), stem cell factor, and Flt3-ligand produced a population of cells that have the ability to proliferate and develop properties enabling them to enhance tissue regeneration. The goal of this study was to assess in vitro cultured CD34+ cells in a setting where they would eventually be rejected so we could isolate paracrine signaling mediated therapeutic effect from the therapeutic effect due to engraftment and differentiation. To achieve this, we used db/db mice as a model for diabetic skin ulcers. Here, we report that in vitro cultured UCB CD34+ cells from frozen units can accelerate wound healing and resulted in the regeneration of full thickness skin. This study demonstrates a new indication for banked UCB units in the area of tissue regeneration. Stem Cells Translational Medicine 2018;7:591-601.

Cardinal role of the intrarenal renin-angiotensin system in the pathogenesis of diabetic nephropathy

Diabetes mellitus is one of the most prevalent diseases and is associated with increased incidence of structural and functional derangements in the kidneys, eventually leading to end-stage renal disease in a significant fraction of afflicted individuals. The renoprotective effects of renin-angiotensin system (RAS) blockade have been established; however, the mechanistic pathways have not been fully elucidated. In this review article, the cardinal role of an activated RAS in the pathogenesis of diabetic nephropathy (DN) is discussed with a focus on 4 themes: (1) introduction to RAS cascade, (2) intrarenal RAS in diabetes, (3) clinical outcomes of RAS blockade in DN, and (4) potential of urinary angiotensinogen as an early biomarker of intrarenal RAS status in DN. This review article provides a mechanistic rational supporting the hypothesis that an activated intrarenal RAS contributes to the pathogenesis of DN and that urinary angiotensinogen levels provide an index of intrarenal RAS activity.

Cardinal Role of the Intrarenal Renin-Angiotensin System in the Pathogenesis of Diabetic Nephropathy

Diabetes mellitus is one of the most prevalent diseases and is associated with increased incidence of structural and functional derangements in the kidneys, eventually leading to end-stage renal disease in a significant fraction of afflicted individuals. The renoprotective effects of renin-angiotensin system (RAS) blockade have been established; however, the mechanistic pathways have not been fully elucidated. In this review article, the cardinal role of an activated RAS in the pathogenesis of diabetic nephropathy (DN) is discussed with a focus on 4 themes: (1) introduction to RAS cascade, (2) intrarenal RAS in diabetes, (3) clinical outcomes of RAS blockade in DN, and (4) potential of urinary angiotensinogen as an early biomarker of intrarenal RAS status in DN. This review article provides a mechanistic rational supporting the hypothesis that an activated intrarenal RAS contributes to the pathogenesis of DN and that urinary angiotensinogen levels provide an index of intrarenal RAS activity.

The role of peroxisome proliferator-activated receptors in pulmonary vascular disease

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear hormone receptor superfamily that regulate diverse physiological processes ranging from lipogenesis to inflammation. Recent evidence has established potential roles of PPARs in both systemic and pulmonary vascular disease and function. Existing treatment strategies for pulmonary hypertension, the most common manifestation of pulmonary vascular disease, are limited by an incomplete understanding of the underlying disease pathogenesis and lack of efficacy indicating an urgent need for new approaches to treat this disorder. Derangements in pulmonary endothelial-derived mediators and endothelial dysfunction have been shown to play a pivotal role in pulmonary hypertension pathogenesis. Therefore, the following review will focus on selected mediators implicated in pulmonary vascular dysfunction and evidence that PPARs, in particular PPARγ, participate in their regulation and may provide a potential novel therapeutic target for the treatment of pulmonary hypertension.

Angiotensin-(1-7) and low-dose angiotensin II infusion reverse salt-induced endothelial dysfunction via different mechanisms in rat middle cerebral arteries

The goals of this study were to 1) determine the acute effect of ANG-(1-7) on vascular tone in isolated middle cerebral arteries (MCAs) from Sprague-Dawley rats fed a normal salt (NS; 0.4% NaCl) diet, 2) evaluate the ability of chronic intravenous infusion of ANG-(1-7) (4 ng·kg(-1)·min(-1)) for 3 days to restore endothelium-dependent dilation to acetylcholine (ACh) in rats fed a high-salt (HS; 4% NaCl) diet, and 3) determine whether the amelioration of endothelial dysfunction by ANG-(1-7) infusion in rats fed a HS diet is different from the protective effect of low-dose ANG II infusion in salt-fed rats. MCAs from rats fed a NS diet dilated in response to exogenous ANG-(1-7) (10(-10)-10(-5) M). Chronic ANG-(1-7) infusion significantly reduced vascular superoxide levels and restored the nitric oxide-dependent dilation to ACh (10(-10)-10(-5) M) that was lost in MCAs of rats fed a HS diet. Acute vasodilation to ANG-(1-7) and the restoration of ACh-induced dilation by chronic ANG-(1-7) infusion in rats fed a HS diet were blocked by the Mas receptor antagonist [D-ALA(7)]-ANG-(1-7) or the ANG II type 2 receptor antagonist PD-123319 and unaffected by ANG II type 1 receptor blockade with losartan. The restoration of ACh-induced dilation in MCAs of HS-fed rats by chronic intravenous infusion of ANG II (5 ng·kg(-1)·min(-1)) was blocked by losartan and unaffected by d-ALA. These findings demonstrate that circulating ANG-(1-7), working via the Mas receptor, restores endothelium-dependent vasodilation in cerebral resistance arteries of animals fed a HS diet via mechanisms distinct from those activated by low-dose ANG II infusion.

Hypertension and atrial fibrillation

Atrial fibrillation (AF) is an emerging public health problem. The most important risk factor for developing chronic AF is uncontrolled hypertension. Uncontrolled hypertension promotes the initiation and perpetuation of AF through atrial remodeling. Experimental evidence has demonstrated the important role of the renin-angiotensin system in atrial remodeling. Retrospective analysis of several large clinical trials and small prospective trials suggests the beneficial role of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in preventing the onset and recurrence of AF in different populations. Several large prospective trials with longer follow-up periods are in progress. These trials may provide definitive evidence for the use of these agents in the prevention of AF.

Lessons in hypertension from new clinical trials

Three important principles have emerged from recent epidemiologic and clinical studies in hypertension. First, patients with hypertension most often have other cardiovascular risk factors such as obesity and diabetes. Second, hypertension remains grossly undertreated. Third, at blood pressure levels once considered "high-normal," early organ damage may already be taking place in patients with multiple risk factors that, without treatment, can eventually lead to cardiovascular morbidity and mortality. The concept of evaluating global or overall risk is gaining wide acceptance, and US treatment guidelines may soon reflect these findings and assist clinicians in identifying individuals who are most likely to benefit from therapy. Results from clinical trials suggest that among the various pharmacologic agents available to treat hypertension, blockers of the renin-angiotensin system are effective in type 2 diabetes and chronic kidney disease, conditions that often occur in conjunction with hypertension.

Blocking the renin-angiotensin system: dual- versus mono-therapy

The renin-angiotensin system (RAS) plays an important role in the pathogenesis of cardiovascular disease. One of the effects of the activated RAS is target-organ damage, in part due to their effects on causing hypertension. Blocking angiotensin-converting enzyme (ACE) with inhibitors has been shown to attenuate the pathological effects of the RAS. Clinical trials have shown that ACE inhibition improves outcomes in the prevention of acute myocardial infarction, lowering the morbidity and mortality in congestive heart failure, and attenuates renal dysfunction. There is recent evidence to show that angiotensin receptor blockers (ARBs) have similar efficacy to ACE inhibitors in reducing cardiovascular outcomes. The wealth of information obtained regarding the beneficial effects of RAS inhibition on clinical outcome has been focused on monotherapy with either ARB or ACE inhibition. Evidence from some trials suggests that better overall inhibition of RAS by dual therapy may improve clinical outcomes. Combination therapy has been shown to be beneficial in patients with congestive heart failure or renal disease. The Valsartan in Acute Myocardial Infarction Trial (VALIANT) trial showed equal benefit of either ARB or ACE inhibition with reduction in primary end points in postmyocardial infarction patients, but there was no further benefit from dual therapy in reducing outcomes. In the recent ONTARGET study, there was further evidence that ARBs are equal to ACE inhibitors in reducing cardiovascular events. In Ongoing Telmisartan, Ramipril, or Both in Patients at High Risk for Vascular Events (ONTARGET), combined RAS blockade did not have any added benefit but resulted in increased risk of adverse outcomes. In the Candesartan in Heart Failure (CHARM) and the Valsartan Heart Failure Trial (Val-HeFT) trials of patients with severe heart failure, the addition of an ARB to an ACE inhibitor reduced cardiac mortality and lowered hospital admissions. Whether or not dual therapy is beneficial in patients with diabetic renal failure should be clarified by future studies. Overall, patients receiving dual therapy, if clinically justified, should be monitored closely for potential adverse effects.

Use of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker therapy to reduce cardiovascular events in high-risk patients: part 2

As presented previously in Part 1 of this 2-part article, many long-term clinical trials provide overwhelming evidence of the benefits of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) across the cardiovascular continuum. Trials also indicate additive or synergistic effects of combination therapy in renal disease and heart failure. Part 2, which is presented here, discusses the extensive interaction of the renin-angiotensin system (RAS) with the cellular and molecular pathophysiology of cardiovascular disease and the cross-continuum effects of ARBs and ACE inhibitors, which raises the possibility that RAS inhibition can offer protection in high-risk patients who do not have symptoms. Although trial evidence supports the effectiveness of monotherapy, the benefits of combined ACE inhibitor/ARB therapy in high-risk patients await confirmation. Ongoing clinical research will provide new and important information regarding the efficacy of specific combination (ACE inhibitor/ARB) therapies.

The effect of oral contraceptives on the nitric oxide system and renal function

We have demonstrated that oral contraceptive (OC) users exhibit elevated angiotensin II levels and angiotensin II type 1 receptor expression, indicative of renin-angiotensin system (RAS) activation, yet the renal and systemic consequences are minimal, suggesting that there is increased vasodilatory activity, counteracting the effect of RAS activation. We hypothesized that the nitric oxide (NO) system would be upregulated in OC users and that this would be reflected by a blunted hemodynamic response to l-arginine infusion. All subjects were studied after a 7-day controlled sodium and protein diet. Inulin and para-aminohippurate clearance techniques were used to assess renal function. l-Arginine was infused at 100, 250, and 500 mg/kg, each over 30 min. Skin endothelial NO synthase mRNA expression was assessed by real-time PCR. While OC nonusers exhibited significant increases in effective renal plasma flow (670.8 +/- 35.6 to 816.2 +/- 59.7 ml.min(-1).1.73 m(-2)) and glomerular filtration rate (133.4 +/- 4.3 to 151.0 +/- 5.7 ml.min(-1).1.73 m(-2), P = 0.04) and declines in renal vascular resistance (81.1 +/- 6.1 to 63.5 +/- 6.2 mmHg.ml(-1).min, P = 0.001) at the lower l-arginine infusion rates, the responses in OC users were blunted. While l-arginine reduced mean arterial pressure at the 250 and 500 mg/kg doses in OC nonusers, OC users only exhibited a decrease in mean arterial pressure at the highest infusion rate. In contrast, tissue endothelial NO synthase mRNA levels were higher in the OC users (P = 0.04). In summary, these findings suggest that the NO system is upregulated by OC use in young, healthy women. Increased activity of the NO pathway may modulate the hemodynamic effects of RAS activation in OC users.

The effect of angiotensin receptor blockers for preventing atrial fibrillation

Atrial fibrillation is the most common sustained cardiac arrhythmia in clinical practice, and causes significant burden to patients and health care systems. Clinicians treat existing atrial fibrillation with anticoagulation and/or drugs that utilize either a rate or rhythm control strategy. It remains unclear how best to reduce cardiovascular morbidity and mortality in this population. Prevention of atrial fibrillation using angiotensin receptor blockers, which affect ion currents and refractoriness in atrial myocytes, regress or prevent atrial fibrosis, decrease left atrial size, regress left ventricular hypertrophy, modulate sympathetic nerve activity, reduce inflammation, and reduce blood pressure, may become an important and desirable alternative.

Angiotensin receptor blockers versus angiotensin-converting enzyme inhibitors: where do we stand now?

Cardiovascular disease represents a continuum that starts with risk factors, such as hypertension, and progresses to atherosclerosis, target organ damage, and ultimately leads to heart failure or stroke. Renin-angiotensin-aldosterone system (RAAS) blockade with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) has been shown to be beneficial at all stages of this continuum. Both classes of agent can prevent or reverse endothelial dysfunction and atherosclerosis, thereby potentially reducing the risk of cardiovascular events. Such a reduction has been shown with ACE inhibitors in patients with coronary artery disease, but no such data are currently available for ARBs. Both ACE inhibitors and ARBs have been shown to reduce damage in target organs, such as the heart and kidney, and to decrease cardiovascular mortality and morbidity in patients with congestive heart failure. Trials, such as the Ongoing Telmisartan Alone in Combination with Ramipril Global Endpoint Trial (ONTARGET) and the Telmisartan Randomised Assessment Study in ACE-Intolerant Subjects with Cardiovascular Disease (TRANSCEND), that compare telmisartan, ramipril, and their combination in high-risk patients with vascular end-organ damage, should provide important new insights into the benefits of intervention with RAS blockade along the cardiorenovascular continuum.

Use of predictive markers to improve cardiovascular protection

Together with other modifiable cardiovascular risk factors, hypertension heavily contributes to the global burden of cardiovascular morbidity and mortality, as well as to the increase in individual absolute cardiovascular risk. Comparison of the effectiveness of different therapies in reducing the incidence of major cardiovascular events has classically required the evaluation of major 'hard' end points. In view of the long natural history of hypertension, however, it appears very useful to monitor modifications in measurable 'intermediate' end points or 'disease markers'. This approach may provide more accurate individual risk stratification and a better evaluation of the efficacy of a given treatment in preventing or modifying the course of target organ damage. This may represent a valuable and affordable strategy in clinical practice allowing the evaluation of both patient prognosis and the effectiveness of antihypertensive treatment over time.

Complications of hypertension and the role of angiotensin receptor blockers in hypertension trials

Hypertension is a high-prevalence disease that may affect several organs. In recent years, data have accumulated indicating that angiotensin II receptor blockers (ARBs) may have a supplementary effect beyond lowering blood pressure. The aim of this review is to evaluate the impact of ARBs on the most important complications of hypertension--heart, cerebrovascular and renal diseases, and metabolic complications--based on the findings from large clinical hypertension trials. The results may indicate that ARBs have a superior effect compared with placebo or other antihypertensive drugs in order to prevent left ventricular hypertrophy, atrial fibrillation, stroke, renal disease and diabetes mellitus, while there appears to be no blood pressure-independent superior effect of ARBs regarding prevention of myocardial infarction or heart failure.

The renin-angiotensin system and insulin resistance

Insulin resistance upregulates the renin-angiotensin system (RAS), which contributes to the pathogenesis of hypertension, heart failure, and atherosclerosis. RAS inhibition decreases cardiovascular and renal morbidity and mortality and the incidence of new-onset type 2 diabetes. To the same degree, angiotensin II impairs insulin signaling, induces inflammation via the nuclear factor-kappaB pathway, and reduces nitric oxide availability and facilitates vasoconstriction, leading to insulin resistance and endothelial dysfunction. Thus, the RAS, insulin resistance, and inflammation perpetuate each other and coordinately contribute to endothelial dysfunction, vascular injury, and atherosclerosis.

Effective treatment of hypertension by AT(1) receptor antagonism: the past and future of telmisartan

Lowering blood pressure is the most effective treatment method to ensure a reduction in the total risk for cardiovascular morbidity and mortality. The renin-angiotensin system plays an important role in volume homeostasis and blood pressure regulation and is a target for several groups of pharmaceutical agents. Angiotensin II receptor blockers represent the newest class of antihypertensive compounds. They prevent the binding of angiotensin II to the subtype 1 receptor (AT(1)), which is believed to mediate most of the physiological actions relevant to the regulation of blood pressure. Telmisartan, a widely used AT(1) receptor antagonist, is a highly selective compound with high potency, a long duration of action and a tolerability profile similar to placebo. Numerous randomized clinical trials and community-based studies have demonstrated that oral telmisartan and combinations of telmisartan with hydrochlorothiazide are at least as effective in lowering blood pressure as all other hypertensive medications. This has been demonstrated in different populations of adult patients with mild-to-moderate essential hypertension, including patients with coexisting Type 2 diabetes, metabolic syndrome or renal impairment. Several large-scale, long-term, clinical endpoint studies are in progress to assess the beneficial effects of telmisartan on hypertension-related end-organ damage in patients at high risk of renal, cardiac and vascular damage whose blood pressure is well controlled. The most recent data from clinical trials and latest research regarding telmisartan will be reviewed in this article.