The effect of direct renin inhibition alone and in combination with ACE inhibition on endothelial function, arterial stiffness, and renal function in type 1 diabetes

Mathematical modeling of antihypertensive therapy

Hypertension is a multifactorial disease arising from complex pathophysiological pathways. Individual characteristics of patients result in different responses to various classes of antihypertensive medications. Therefore, evaluating the efficacy of therapy based on in silico predictions is an important task. This study is a continuation of research on the modular agent-based model of the cardiovascular and renal systems (presented in the previously published article). In the current work, we included in the model equations simulating the response to antihypertensive therapies with different mechanisms of action. For this, we used the pharmacodynamic effects of the angiotensin II receptor blocker losartan, the calcium channel blocker amlodipine, the angiotensin-converting enzyme inhibitor enalapril, the direct renin inhibitor aliskiren, the thiazide diuretic hydrochlorothiazide, and the β-blocker bisoprolol. We fitted therapy parameters based on known clinical trials for all considered medications, and then tested the model's ability to show reasonable dynamics (expected by clinical observations) after treatment with individual drugs and their dual combinations in a group of virtual patients with hypertension. The extended model paves the way for the next step in personalized medicine that is adapting the model parameters to a real patient and predicting his response to antihypertensive therapy. The model is implemented in the BioUML software and is available at https://gitlab.sirius-web.org/virtual-patient/antihypertensive-treatment-modeling.

Cardiometabolic and Kidney Protection in Kidney Transplant Recipients With Diabetes: Mechanisms, Clinical Applications, and Summary of Clinical Trials

Kidney transplantation is the therapy of choice for patients with end-stage renal disease. Preexisting diabetes is highly prevalent in kidney transplant recipients (KTR), and the development of posttransplant diabetes is common because of a number of transplant-specific risk factors such as the use of diabetogenic immunosuppressive medications and posttransplant weight gain. The presence of pretransplant and posttransplant diabetes in KTR significantly and variably affect the risk of graft failure, cardiovascular disease (CVD), and death. Among the many available therapies for diabetes, there are little data to determine the glucose-lowering agent(s) of choice in KTR. Furthermore, despite the high burden of graft loss and CVD among KTR with diabetes, evidence for strategies offering cardiovascular and kidney protection is lacking. Recent accumulating evidence convincingly shows glucose-independent cardiorenal protective effects in non-KTR with glucose-lowering agents, such as sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor agonists. Therefore, our aim was to review cardiorenal protective strategies, including the evidence, mechanisms, and rationale for the use of these glucose-lowering agents in KTR with diabetes.

Management of hypertension and renin-angiotensin-aldosterone system blockade in adults with diabetic kidney disease: Association of British Clinical Diabetologists and the Renal Association UK guideline update 2021

People with type 1 and type 2 diabetes are at risk of developing progressive chronic kidney disease (CKD) and end-stage kidney failure. Hypertension is a major, reversible risk factor in people with diabetes for development of albuminuria, impaired kidney function, end-stage kidney disease and cardiovascular disease. Blood pressure control has been shown to be beneficial in people with diabetes in slowing progression of kidney disease and reducing cardiovascular events. However, randomised controlled trial evidence differs in type 1 and type 2 diabetes and different stages of CKD in terms of target blood pressure. Activation of the renin-angiotensin-aldosterone system (RAAS) is an important mechanism for the development and progression of CKD and cardiovascular disease. Randomised trials demonstrate that RAAS blockade is effective in preventing/ slowing progression of CKD and reducing cardiovascular events in people with type 1 and type 2 diabetes, albeit differently according to the stage of CKD. Emerging therapy with sodium glucose cotransporter-2 (SGLT-2) inhibitors, non-steroidal selective mineralocorticoid antagonists and endothelin-A receptor antagonists have been shown in randomised trials to lower blood pressure and further reduce the risk of progression of CKD and cardiovascular disease in people with type 2 diabetes. This guideline reviews the current evidence and makes recommendations about blood pressure control and the use of RAAS-blocking agents in different stages of CKD in people with both type 1 and type 2 diabetes.

Dual Blockade of the Renin-Angiotensin System: A Strategy that Should Be Reconsidered in Cardiorenal Diseases?

Studies on pharmacological mechanisms demonstrated that a strategy of dual renin-angiotensin system (RAS) blockade may have a synergistic effect in the treatment of cardiorenal diseases and may reduce adverse reactions. However, some previous clinical studies reported that dual RAS blockade did not significantly benefit many patients with cardiorenal diseases and increased the risk of hyperkalemia, hypotension and renal function damage. Therefore, the current clinical guidelines suggest that the combined use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) should be used with caution in the clinic. However, these studies enrolled older patients with cardiovascular risk factors, and the results of these trials may not be generalized to the overall population. Some clinical evidence suggests that the combination of low-dose ACEIs and ARBs leads to more effective RAS blockade with few adverse effects. The advent of new RAS inhibitors with superior pharmacological effects provides a more suitable drug choice for individualized therapy for dual RAS blockade. Therefore, the choice of appropriate ARBs/ACEIs for individualized therapy based on patient condition may be a better way to improve the efficiency and safety of the dual RAS blockade strategy.

Effect of direct renin inhibition on vascular function after long-term treatment with aliskiren in hypertensive and diabetic patients

OBJECTIVE

We tested the hypothesis that chronic treatment with the direct renin inhibitor aliskiren improves vascular function in resistance and conduit arteries of type two diabetic and hypertensive patients.

METHOD

Sixteen patients with mild essential hypertension and with a previous diagnosis of noninsulin-dependent diabetes mellitus were included in the study. Patients were then randomized to aliskiren (150 mg once daily, n = 9), or ramipril (5 mg once daily, n = 7). Each patient underwent a biopsy of the subcutaneous tissue and small arteries were dissected and mounted on a pressurized micromyograph to evaluate endothelium dependent vasorelaxation in response to acetylcholine ± N omega-nitro-L-arginine methyl ester hydrochloride in vessels precontracted with norepinephrine. Endothelial function has been quantified also in large conduit arteries by flow-mediated dilation.

RESULTS

A similar office blood pressure-lowering effect was observed with the two drugs, although changes in DBP were not statistically significant in the ramipril group. Aliskiren significantly improved endothelium-dependent relaxation in subcutaneous resistance arteries, as well as increased flow-mediated dilation in conduit arteries, whereas the effects induced by ramipril did not reach statistical significance. Only aliskiren significantly increased the expression of p1177-endothelial nitric oxide synthase in the endothelium. Both aliskiren and ramipril had a negligible effect on markers of oxidative stress.

CONCLUSION

Aliskiren restored endothelial function and induced a more prompt peripheral vasodilation in hypertensive and diabetic patients possibly through the increased production of nitric oxide via the enhanced expression and function of the active phosphorylated form of endothelial nitric oxide synthase.

Renal Benefits of SGLT 2 Inhibitors and GLP-1 Receptor Agonists: Evidence Supporting a Paradigm Shift in the Medical Management of Type 2 Diabetes

Diabetic nephropathy (DN) is one of the most perilous side effects of diabetes mellitus type 1 and type 2 (T1DM and T2DM).). It is known that sodium/glucose cotransporter 2 inhibitors (SGLT 2i) and glucagone like peptide-1 receptor agonists (GLP-1 RAs) have renoprotective effects, but the molecular mechanisms are still unknown. In clinical trials GLP-1 analogs exerted important impact on renal composite outcomes, primarily on macroalbuminuria, possibly through suppression of inflammation-related pathways, however enhancement of natriuresis and diuresis is also one of possible mechanisms of nephroprotection. Dapagliflozin, canagliflozin, and empagliflozin are SGLT2i drugs, useful in reducing hyperglycemia and in their potential renoprotective mechanisms, which include blood pressure control, body weight loss, intraglomerular pressure reduction, and a decrease in urinary proximal tubular injury biomarkers. In this review we have discussed the potential synergistic and/or additive effects of GLP 1 RA and SGLT2 inhibitors on the primary onset and progression of kidney disease, and the potential implications on current guidelines of diabetes type 2 management.

Smooth Muscle Cell-Specific Disruption of the BBSome Causes Vascular Dysfunction

The BBSome-a complex consisting of 8 Bardet-Biedl syndrome proteins-is involved in the regulation of various cellular processes. Recently, the BBSome complex has emerged as an important regulator of cardiovascular function with implications for disease. In this study, we examined the role of the BBSome in vascular smooth muscle and its effects on the regulation of cardiovascular function. Smooth muscle-specific disruption of the BBSome through tamoxifen-inducible deletion of Bbs1 gene-a critical component of the BBSome complex-reduces relaxation and enhances contractility of vascular rings and increases aortic stiffness independent of changes in arterial blood pressure. Mechanistically, we demonstrate that smooth muscle Bbs1 gene deletion increases vascular angiotensinogen gene expression implicating the renin-angiotensin system in these altered cardiovascular responses. Additionally, we report that smooth muscle-specific Bbs1 knockout mice demonstrate enhanced ET-1 (endothelin-1)-induced contractility of mesenteric arteries-an effect reversed by blockade of the AT1 (angiotensin type 1 receptor) with losartan. These findings highlight the importance of the smooth muscle BBSome in the control of vascular function and arterial stiffness through modulation of renin-angiotensin system signaling.

Elevated plasma cyclic guanosine monophosphate may explain greater efferent arteriolar tone in adults with longstanding type 1 diabetes: A brief report

Cyclic guanosine monophosphate (cGMP) influences intrarenal hemodynamics in animal models, but the relationship between cGMP and renal function in adults with type 1 diabetes (T1D) remains unclear. In this study, plasma cGMP correlated with efferent arteriolar resistance, effective renal plasma flow, and renal vascular resistance in adults with T1D.

SGLT-2 Inhibitors in Heart Failure: Implications for the Kidneys

PURPOSE OF REVIEW

This review aims to summarize the renal effects of sodium-glucose transporter-2 (SGLT-2) inhibitors and their potential implications in heart failure pathophysiology.

RECENT FINDINGS

In patients with diabetes and established atherosclerosis, the SGLT-2 inhibitor empagliflozin versus placebo significantly reduced the rate of heart failure admissions with 35%. Moreover, empagliflozin slowed kidney disease progression and reduced the need for renal replacement therapy. SGLT-2 inhibitors inhibit proximal tubular sodium and chloride reabsorption, leading to increased nephron flux throughout the distal renal tubules, most notably at the level of the macula densa. Afferent arteriolar vasoconstriction is promoted through tubulo-glomerular feedback and reduces glomerular capillary hydrostatic pressure, relieving podocyte stress and explaining renal preservation. Further, plasma volume is contracted and natriuresis promoted without inducing neurohumoral activation. Finally, SGLT-2 inhibitors may improve endothelial function and energy metabolism efficiency. Together, these promising features place them as a potential novel treatment for heart failure.

Role of SGLT2 Inhibitors in Patients with Diabetes Mellitus and Heart Failure

PURPOSE OF REVIEW

This review aims to summarize the evidence on cardiovascular risks and benefits of glucose-lowering drugs in diabetic patients, with a particular focus on the role of sodium-glucose transporter-2 (SGLT-2) inhibitors and their promising potential as a heart failure treatment.

RECENT FINDINGS

The SGLT-2 inhibitor empagliflozin has emerged as the first glucose-lowering drug to lower cardiovascular mortality in diabetes with an unprecedented 38% relative risk reduction. In addition, empagliflozin significantly reduced the rate of heart failure admissions with 35% when compared to placebo in diabetic patients with established atherosclerosis. SGLT-2 inhibitors should be considered as a first-line drug to achieve glycemic control in diabetic patients at high risk for cardiovascular diseases and heart failure in particular. As SGLT-2 inhibitors target different pathophysiological pathways in heart failure, they might even be considered in the broader population without diabetes, but this remains the topic of further study.

Diabetic nephropathy: Time to withhold development and progression - A review

The recent discoveries in the fields of pathogenesis and management of diabetic nephropathy have revolutionized the knowledge about this disease. Little was added to the management of diabetic nephropathy after the introduction of renin angiotensin system blockers. The ineffective role of the renin- angiotensin system blockers in primary prevention of diabetic nephropathy in type 1 diabetes mellitus necessitated the search for other early therapeutic interventions that target alternative pathogenic mechanisms. Among the different classes of oral hypoglycemic agents, recent studies highlighted the distinguished mechanisms of sodium glucose transporter 2 blockers and dipeptidyl peptidase-4 inhibitors that settle their renoprotective actions beyond the hypoglycemic effects. The introduction of antioxidant and anti-inflammatory agents to this field had also added wealth of knowledge. However, many of these agents are still waiting well-designed clinical studies in order to prove their beneficial therapeutic role. The aim of this review of literature is to highlight the recent advances in understanding the pathogenesis, diagnosis, the established and the potential renoprotective therapeutic agents that would prevent the development or the progression of diabetic nephropathy.

Influence of sex on hyperfiltration in patients with uncomplicated type 1 diabetes

The aim of this analysis was to examine sex-based differences in renal segmental resistances in healthy controls (HCs) and patients with type 1 diabetes (T1D). We hypothesized that hyperfiltration-an early hemodynamic abnormality associated with diabetic nephropathy-would disproportionately affect women with T1D, thereby attenuating protection against the development of renal complications. Glomerular hemodynamic parameters were evaluated in HC (n = 30) and in normotensive, normoalbuminuric patients with T1D and either baseline normofiltration [n = 36, T1D-N, glomerular filtration rate (GFR) 90-134 ml·min^-1·1.73 m²] or hyperfiltration (n = 32, T1D-H, GFR ≥ 135 ml·min^-1·1.73 m²) during euglycemic conditions (4-6 mmol/l). Gomez's equations were used to derive efferent (R_E) and afferent (R_A) arteriolar resistances, glomerular hydrostatic pressure (P_GLO) from inulin (GFR) and paraaminohippurate [effective renal plasma flow (ERPF)] clearances, plasma protein and estimated ultrafiltration coefficients (K_FG). Female patients with T1D with hyperfiltration (T1D-H) had higher R_E (1,985 ± 487 vs. 1,381 ± 296 dyne·sec^-1·cm^-5, P < 0.001) and filtration fraction (FF, 0.20 ± 0.047 vs. 0.16 ± 0.03 P < 0.05) and lower ERPF (876 ± 245 vs. 1,111 ± 298 134 ml·min^-1·1.73 m²P < 0.05) compared with male T1D-H patients. Overall, T1D-H patients had higher P_GLO and lower R_A vs. HC subjects, although there were no sex-based differences. In conclusion, female T1D-H patients had higher R_E and FF and lower ERPF than their male counterparts with no associated sex differences in R_A Prospective intervention studies should consider sex as a modifier of renal hemodynamic responses to renal protective therapies.

Sodium-Glucose Cotransporter-2 Inhibition and the Glomerulus: A Review

Blood glucose-lowering treatment options generally target insulin action or beta-cell function. In diabetes, expression of the sodium-glucose cotransporter-2 (SGLT2) genes is up-regulated and renal threshold increased, resulting in increased glucose reabsorption from glomerular filtrate, reducing urinary glucose excretion and worsening the hyperglycemic condition. The SGLT2 inhibitors (SGLT2i) are a novel class of anti-diabetic drugs that lower blood glucose levels through the suppression of renal glucose reabsorption thereby promoting renal glucose excretion. The efficacy of SGLT2i is reduced in renal impairment because the ability of glucose-lowering is directly proportional to glomerular filtration rate. On the other hand, ongoing research suggests that SGLT2i may offer potential nephroprotection in diabetes. The SGLT2i have been shown to reduce glomerular hyperfiltration, systemic and intraglomerular pressure and the biochemical progression of chronic kidney disease. Additional mechanisms through which SGLT2i exert nephroprotection may include normalizing blood pressure and uricemia. This review explores this bidirectional relationship of the SGLT2i and the glomerulus. While SGLT2i exhibit reduced efficacy in later stages, they exhibit nephroprotective effects in early stages of renal impairment.

Funding: Janssen India (Pharmaceutical division of Johnson & Johnson).

Plasma uric acid effects on glomerular haemodynamic profile of patients with uncomplicated Type 1 diabetes mellitus

AIMS

Increased plasma uric acid (PUA) levels are associated with impaired renal function in patients with Type 1 diabetes, but the mechanisms are not well understood. Our aim was to evaluate whether higher PUA levels are associated with increased afferent arteriolar resistance in patients with Type 1 diabetes vs. healthy controls, thereby influencing renal function.

METHODS

PUA, GFR (inulin) and effective renal plasma flow (ERPF; para-aminohippurate) were measured in 70 otherwise healthy patients with Type 1 diabetes and 60 healthy controls. Gomez's equations were used to estimate afferent (RA ) and efferent (RE ) arteriolar resistances, glomerular hydrostatic pressure (PGLO ) and filtration pressure (ΔPF ). The relationships between PUA and glomerular haemodynamic parameters were evaluated by univariable linear regression correlation coefficients.

RESULTS

In patients with Type 1 diabetes, higher PUA correlated with lower PGLO (P = 0.002) and ΔPF (P = 0.0007), with higher RA (P = 0.001), but not with RE (P = 0.55). These associations were accompanied by correlations between higher PUA with lower GFR (P = 0.0007), ERPF (P = 0.008), RBF (P = 0.047) and higher RVR (P = 0.021). There were no significant correlations between PUA and renal haemodynamic parameters in the healthy controls.

CONCLUSIONS

The association between higher PUA with lower GFR and lower ERPF in patients with Type 1 diabetes is driven by alterations in the estimated RA . PUA-mediated RA may be caused by increased tone or thickening of the afferent renal arteriole, which might potentiate renal injury by causing ischaemia to the renal microcirculation.

Sodium Glucose Cotransporter 2 Inhibitors in the Treatment of Diabetes Mellitus: Cardiovascular and Kidney Effects, Potential Mechanisms, and Clinical Applications

Sodium-glucose cotransporter-2 (SGLT2) inhibitors, including empagliflozin, dapagliflozin, and canagliflozin, are now widely approved antihyperglycemic therapies. Because of their unique glycosuric mechanism, SGLT2 inhibitors also reduce weight. Perhaps more important are the osmotic diuretic and natriuretic effects contributing to plasma volume contraction, and decreases in systolic and diastolic blood pressures by 4 to 6 and 1 to 2 mm Hg, respectively, which may underlie cardiovascular and kidney benefits. SGLT2 inhibition also is associated with an acute, dose-dependent reduction in estimated glomerular filtration rate by ≈5 mL·min(-1)·1.73 m(-2) and ≈30% to 40% reduction in albuminuria. These effects mirror preclinical observations suggesting that proximal tubular natriuresis activates renal tubuloglomerular feedback through increased macula densa sodium and chloride delivery, leading to afferent vasoconstriction. On the basis of reduced glomerular filtration, glycosuric and weight loss effects are attenuated in patients with chronic kidney disease (estimated glomerular filtration rate <60 mL·min(-1)·1.73 m(-2)). In contrast, blood pressure lowering, estimated glomerular filtration rate, and albuminuric effects are preserved, and perhaps exaggerated in chronic kidney disease. With regard to long-term clinical outcomes, the EMPA-REG OUTCOME trial (Empagliflozin, Cardiovascular Outcomes, and Mortality in Type 2 Diabetes) in patients with type 2 diabetes mellitus and established cardiovascular disease randomly assigned to empagliflozin versus placebo reported a 14% reduction in the primary composite outcome of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, and >30% reductions in cardiovascular mortality, overall mortality, and heart failure hospitalizations associated with empagliflozin, even though, by design, the hemoglobin A1c difference between the randomized groups was marginal. Aside from an increased risk of mycotic genital infections, empagliflozin-treated patients had fewer serious adverse events, including a lower risk of acute kidney injury. In light of the EMPA-REG OUTCOME results, some diabetes clinical practice guidelines now recommend that SGLT2 inhibitors with proven cardiovascular benefit be prioritized in patients with type 2 diabetes mellitus who have not achieved glycemic targets and who have prevalent atherosclerotic cardiovascular disease. With additional cardiorenal protection trials underway, sodium-related physiological effects of SGLT2 inhibitors and clinical correlates of natriuresis, such as the impact on blood pressure, heart failure, kidney protection, and mortality, will be a major management focus.

Impact of Renin-Angiotensin System Inhibitors on Long-Term Clinical Outcomes of Patients With Coronary Artery Spasm

Background

Coronary artery spasm (CAS) is a well‐known endothelial dysfunction, and a major cause of vasospastic angina (VSA). The renin–angiotensin system (RAS) is known to be closely associated with endothelial function. However, there are only a few studies that investigated the impact of RAS inhibitor on long‐term clinical outcomes in VSA patients.

Methods and Results

A total of 3349 patients with no significant coronary artery disease, diagnosed with CAS by acetylcholine provocation test were enrolled for this study. Significant CAS was defined as having ≥70% narrowing of the artery after incremental injections of 20, 50, and 100 μg of acetylcholine into the left coronary artery. Patients were divided into 2 groups according to whether the prescription included RAS inhibitor or not (RAS inhibitor group: n=666, non‐RAS inhibitor group; n=2683). To adjust for any potential confounders that could cause bias, propensity score matching (PSM) analysis was performed using a logistic regression model. After PSM analysis, 2 matched groups (524 pairs, n=1048 patients, C‐statistic=0.845) were generated and their baseline characteristics were balanced. During the 5‐year clinical follow‐up, the RAS inhibitor group showed a lower incidence of recurrent angina (8.7% versus 14.1%, P=0.027), total death (0.0% versus 1.3%, P=0.045), and total major adverse cardiovascular events (1.0% versus 4.1%, P=0.026) than the non‐RAS inhibitor group.

Conclusions

Chronic RAS inhibitor therapy was associated with lower incidence of cardiovascular events in VSA patients in the 5‐year clinical follow‐up.

Central wave reflection is associated with peripheral arterial resistance in addition to arterial stiffness in subjects without antihypertensive medication

Background

Augmentation index, a marker of central wave reflection, is influenced by age, sex, height, blood pressure, heart rate, and arterial stiffness. However, the detailed haemodynamic determinants of augmentation index, and their relations, remain uncertain. We examined the association of augmentation index with vascular resistance and other haemodynamic and non-haemodynamic factors.

Methods

Background information, laboratory values, and haemodynamics of 488 subjects (239 men, 249 women) without antihypertensive medication were obtained. Indices of central wave reflection, systemic vascular resistance, cardiac function, and pulse wave velocity were measured using continuous radial pulse wave analysis and whole-body impedance cardiography.

Results

In a regression model including only haemodynamic variables, augmentation index in males and female subjects, respectively, was associated with systemic vascular resistance (β = 0.425, β = 0.336), pulse wave velocity (β = 0.409, β = 0.400) (P < 0.001 for all), stroke volume (β = 0.256, β = 0.278) (P = 0.001 for both) and heart rate (β = −0.150, β = −0.156) (P = 0.049 and P = 0.036). When age, height, weight, smoking habits, and laboratory values were included in the regression model, the most significant explanatory variables for augmentation index in males and females, respectively, were age (β = 0.577, β = 0.557) and systemic vascular resistance (β = 0.437, β = 0.295) (P < 0.001 for all). In the final regression model, pulse wave velocity was not a significant explanatory variable for augmentation index, probably due to the high correlation of this variable with age (Spearman’s correlation ≥0.617).

Conclusion

Augmentation index is strongly associated with systemic vascular resistance in addition to arterial stiffness.

Trial registration

ClinicalTrials.gov, NCT01742702.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0303-6) contains supplementary material, which is available to authorized users.

Early changes in cardiovascular structure and function in adolescents with type 1 diabetes

Background

Children with type 1 diabetes (T1D) are at higher risk of early adult-onset cardiovascular disease. We assessed cardiovascular structure and function in adolescents with T1D compared with healthy controls and the relationships between peripheral vascular function and myocardial parameters.

Methods and results

199 T1D [14.4 ± 1.6 years, diabetes duration 6.2 (2.0–12.8) years] and 178 controls (14.4 ± 2.1 years) completed endothelial function by flow mediated vasodilatation (FMD), arterial stiffness using pulse wave velocity (PWV) along with M-mode, pulse wave and tissue Doppler, and myocardial deformation echocardiographic imaging. Systolic (113 ± 10 vs. 110 ± 9 mmHg; p = 0.0005) and diastolic (62 ± 7 vs. 58 ± 7 mmHg; p < 0.0001) blood pressures, carotid femoral PWV and endothelial dysfunction measurements were increased in T1D compared with controls. Systolic and diastolic left ventricular dimensions and function by M-mode and pulse wave Doppler assessment were not significantly different. Mitral valve lateral e’ (17.6 ± 2.6 vs. 18.6 ± 2.6 cm/s; p < 0.001) and a’ (5.4 ± 1.1 vs. 5.9 ± 1.1 cm/s; p < 0.001) myocardial velocities were decreased and E/e’ (7.3 ± 1.2 vs. 6.7 ± 1.3; p = 0.0003) increased in T1D. Left ventricular mid circumferential strain (−20.4 ± 2.3 vs. −19.5 ± 1.7 %; p < 0.001) was higher, whereas global longitudinal strain was lower (−19.0 ± 1.9 vs. −19.8 ± 1.5 % p < 0.001) in T1D.

Conclusions

Adolescents with T1D exhibit early changes in blood pressure, peripheral vascular function and left ventricular myocardial deformation indices with a shift from longitudinal to circumferential shortening. Longitudinal follow-up of these changes in ongoing prospective trials may allow detection of those most at risk for cardiovascular abnormalities including hypertension that could preferentially benefit from early therapeutic interventions.

Clinical Significance of Endothelial Dysfunction in Essential Hypertension

The endothelium is recognized as a major determinant of vascular physiology and pathophysiology. Over the last few decades, a plethora of studies have implicated endothelial dysfunction in the progression of atherosclerosis and the subclinical target organ damage observed in essential hypertension. However, the clinical significance of diagnosing endothelial dysfunction in patients with essential hypertension remains under investigation. Although a number of vascular and non-vascular markers of endothelial dysfunction have been proposed, there is an ongoing quest for a marker in the clinical setting that is optimal, inexpensive, and reproducible. In addition, endothelial dysfunction emerges as a promising therapeutic target of agents that are readily available in clinical practice. In this context, a better understanding of its role in essential hypertension becomes of great importance. Here, we aim to investigate the clinical significance of endothelial dysfunction in essential hypertension by accumulating novel data on (a) early diagnosis using robust markers with prognostic value in cardiovascular risk prediction, (b) the association of endothelial dysfunction with subclinical vascular organ damage, and (c) potential therapeutic targets.

Sodium-glucose cotransporter-2 inhibition and the potential for renal protection in diabetic nephropathy

PURPOSE OF REVIEW

Renal hyperfiltration has been used as a surrogate marker for increased intraglomerular pressure in patients with diabetes mellitus. Previous human investigation examining the pathogenesis of hyperfiltration has focused on the role of neurohormones such as the renin-angiotensin-aldosterone system (RAAS). Unfortunately, RAAS blockade does not completely attenuate hyperfiltration or diabetic kidney injury. More recent work has therefore investigated the contribution of renal tubular factors, including the sodium-glucose cotransporter, to the hyperfiltration state, which is the topic of this review.

RECENT FINDINGS

Novel sodium-glucose cotransporter-2 (SGLT2) inhibitors reduce proximal tubular sodium reabsorption, thereby increasing distal sodium delivery to the macula densa, causing tubuloglomerular feedback, afferent vasoconstriction and decreased hyperfiltration in animals. In humans, SGLT2 inhibition was recently shown to reduce hyperfiltration in normotensive, normoalbuminuric patients with type 1 diabetes. In clinical trials of type 2 diabetes, SGLT2 is associated with significant renal effects, including modest, acute declines in estimated glomerular filtration rate followed by the maintenance of stable renal function, and reduced albuminuria.

SUMMARY

Existing data are supportive of a potential renal-protective role for SGLT2 inhibition in patients with diabetes. Dedicated renal outcome trials are ongoing and have the potential to change the clinical practice.

Glomerular haemodynamic profile of patients with Type 1 diabetes compared with healthy control subjects

AIMS

To evaluate the glomerular haemodynamic profile of patients with Type 1 diabetes with either renal hyperfiltration (GFR ≥ 135 ml/min/1.73 m2 ) or renal normofiltration (GFR 90-134 ml/min/1.73 m2 ) during euglycaemic and hyperglycaemic conditions, and to compare this profile with that of a similar group of healthy control subjects.

METHODS

Gomez's equations were used to derive afferent and efferent arteriolar resistances, glomerular hydrostatic pressure and filtration pressure.

RESULTS

At baseline, during clamped euglycaemia, patients with Type 1 diabetes and hyperfiltration had lower mean ± sd afferent arteriolar resistance than both those with Type 1 diabetes and normofiltration (914 ± 494 vs. 2065 ± 597 dyne/s/cm5 ; P < 0.001) and healthy control subjects (1676 ± 707 dyne/s/cm(5) ; p < 0.001). By contrast, efferent arteriolar resistance was similar in the three groups. Patients with Type 1 diabetes and hyperfiltration also had higher mean ± sd glomerular hydrostatic pressure than both healthy control subjects and patients with Type 1 diabetes and normofiltration (66 ± 6 vs. 60 ± 3 vs. 55 ± 3 mmHg; P < 0.05). Similar findings for afferent arteriolar resistance, efferent arteriolar resistance, glomerular hydrostatic pressure and filtration pressure were observed during clamped hyperglycaemia.

CONCLUSION

Hyperfiltration in Type 1 diabetes is primarily driven by alterations in afferent arteriolar resistance rather than efferent arteriolar resistance. Renal protective therapies should focus on afferent renal arteriolar mechanisms through the use of pharmacological agents that target tubuloglomerular feedback, including sodium-glucose cotransporter 2 inhibitors and incretins.

A low-dose combination of fluvastatin and valsartan: a new "drug" and a new approach for decreasing the arterial age

We have developed a new “drug” and approach that appear to be effective in reducing arterial age. This “drug” represents a low, subtherapeutic dose of statin and sartan and particularly their low-dose combination. The improvement of arterial wall characteristics, also reflecting in a decrease of arterial age, was achieved after a short period of treatment (one month) with the above-mentioned drugs. In addition, we have also implemented a new, innovative therapeutic approach, consisting of intermittent (cyclic) treatment—alternating short “treatment” periods and much longer “rest” periods (when the beneficial effects are still present but gradually decline). This new “drug” and approach both merit further investigation in order to confirm their antiaging efficacy.

Uric acid as a biomarker and a therapeutic target in diabetes

Diabetic nephropathy is a long-standing microvascular complication of diabetes mellitus and is the leading cause of end stage renal disease in developed countries. Current therapeutic strategies used to prevent or delay diabetic nephropathy exert limited clinical protective effects and can have serious adverse effects. Thus, identification of new pharmacologic agents that protect against the initiation and progression of complications of diabetes is of the utmost importance. Uric acid (UA) recently emerged as an inflammatory factor that increases oxidative stress and promotes activation of the renin angiotensin aldosterone system. As a consequence, higher UA levels are associated with various stages of the onset and progression of diabetic nephropathy, including metabolic, cardiovascular and kidney function abnormalities. If UA-lowering drugs, such as the xanthine oxidase inhibitors, block the mechanisms responsible for micro- and macrovascular injury in diabetes, these agents could represent a critical step toward preventing the progression of diabetes. This review focuses on the evidence that supports serum UA levels as a biomarker of renal and cardiovascular risk and as a potential additional therapeutic target in diabetes.

Effect of aliskiren on circulating endothelial progenitor cells and vascular function in patients with type 2 diabetes and essential hypertension

BACKGROUND

The aim of this study was to investigate the effects of aliskiren on vascular function and endothelial progenitor cells (EPCs) in patients with type 2 diabetes and essential hypertension.

METHODS

The study enrolled type 2 diabetic patients aged >50 years under stable glycemic control and first diagnosed mild essential hypertension. In phase A (n = 20), patients received aliskiren 150-300 mg daily for 3 months. In phase B (n = 12), hydrochlorothiazide (HCTZ) 12.5-25mg daily substituted for aliskiren for 3 more months. At baseline and at the end of each phase, we assessed (i) brachial blood pressure (BBP); (ii) central aortic systolic pressure (CSP), aortic augmentation index (Aix), and pulse wave velocity (PWV) as markers of arterial stiffness; (iii) brachial artery flow-mediated dilatation (FMD) as a marker of endothelial function; (iv) left ventricular (LV) twisting and untwisting as markers of LV function and (v) EPC numbers in culture of peripheral blood mononuclear cells.

RESULTS

Aliskiren similarly reduced BBP and CSP, increased FMD (P < 0.001) and EPC numbers (P < 0.001), decreased PWV and Aix (P < 0.05), and improved LV twisting and untwisting (P < 0.05). Although substitution of HCTZ sustained BBP at similar levels, CSP and echocardiographic indices nearly returned at baseline levels, and the improvement of FMD, PWV, Aix, and EPC numbers was abolished.

CONCLUSIONS

Aliskiren had a favorable effect on endothelial function and EPCs, reduced arterial stiffness, and improved LV twisting and untwisting. These effects were independent of BBP lowering, as they were not observed after the achievement of similar values of BBP with HCTZ.

The effect of sex on humanin levels in healthy adults and patients with uncomplicated type 1 diabetes mellitus

Diabetes mellitus (DM) is associated with a loss of renal and vascular protection in women compared with men, but the responsible mechanisms are unclear. Recent experimental work implicated humanin (HN) as a novel cytoprotective hormone in DM. Our goal was to measure sex-related differences in HN levels in uncomplicated type 1 DM patients (T1D) and healthy controls (HC), as well as the interaction between HN, circulating neurohormones, and vascular function. Plasma HN, cGMP and aldosterone, blood pressure (BP), glomerular filtration rate, and effective renal plasma flow (inulin and para-aminohippurate) were measured in HC (11 men, 10 women) and T1D (23 men and 18 women) during clamped euglycemia (4-6 mmol·L(-1)). Plasma HN levels were generally lower in HC men by comparison with the women, but the differences were not statistically significant. In contrast, levels in the T1D men were higher compared with the T1D women (p = 0.026) and HC men (p < 0.0001). In the HC men, but not the women, HN correlated negatively with BP, but not with renal function, cGMP, or aldosterone. In the T1D men, HN negatively correlated with plasma cGMP. In the T1D women, HN did not correlate with neurohormones or vascular function. Future work should determine the role of HN in the pathogenesis of sex-related vascular function differences in DM.

The impact of hyperfiltration on the diabetic kidney

More than two decades ago, hyperfiltration (HF) in diabetes was postulated to be a maladaptive response observed early in the course of diabetic kidney disease (DKD), which may eventually predispose to irreversible damage to nephrons and development of progressive renal disease. Despite this, the potential mechanisms leading to renal HF in diabetes are not fully understood, although several hypotheses have been proposed, including alterations in glomerular haemodynamic function and tubulo-glomerular feedback. Furthermore, the role of HF as a causative factor in renal disease progression is still unclear and warrants further prospective longer-term studies. Although HF has been entrenched as the first stage in the classic albuminuric pathway to end-stage renal disease in DKD, and HF has been shown to predict the progression of albuminuria in many, but not all studies, the concept that HF predisposes to the development of chronic kidney disease (CKD) stage 3, that is, glomerular filtration rate (GFR) decline to<60mL/min/1.73m(2), remains to be proved. Further long-term studies of GFR gradients therefore are required to establish whether HF ultimately leads to decreased kidney function, after adjustment for glycaemic control and other confounders. Whether reversal of HF with therapeutic agents is protective against reducing the risk of development of albuminuria and renal impairment is also worth investigating in prospective randomized trials.

The effect of empagliflozin on arterial stiffness and heart rate variability in subjects with uncomplicated type 1 diabetes mellitus

Background

Individuals with type 1 diabetes mellitus are at high risk for the development of hypertension, contributing to cardiovascular complications. Hyperglycaemia-mediated neurohormonal activation increases arterial stiffness, and is an important contributing factor for hypertension. Since the sodium glucose cotransport-2 (SGLT2) inhibitor empagliflozin lowers blood pressure and HbA1c in type 1 diabetes mellitus, we hypothesized that this agent would also reduce arterial stiffness and markers of sympathetic nervous system activity.

Methods

Blood pressure, arterial stiffness, heart rate variability (HRV) and circulating adrenergic mediators were measured during clamped euglycaemia (blood glucose 4–6 mmol/L) and hyperglycaemia (blood glucose 9–11 mmol/L) in 40 normotensive type 1 diabetes mellitus patients. Studies were repeated after 8 weeks of empagliflozin (25 mg once daily).

Results

In response to empagliflozin during clamped euglycaemia, systolic blood pressure (111 ± 9 to 109 ± 9 mmHg, p = 0.02) and augmentation indices at the radial (-52% ± 16 to -57% ± 17, p = 0.0001), carotid (+1.3 ± 1 7.0 to -5.7 ± 17.0%, p < 0.0001) and aortic positions (+0.1 ± 13.4 to -6.2 ± 14.3%, p < 0.0001) declined. Similar effects on arterial stiffness were observed during clamped hyperglycaemia without changing blood pressure under this condition. Carotid-radial pulse wave velocity decreased significantly under both glycemic conditions (p ≤ 0.0001), while declines in carotid-femoral pulse wave velocity were only significant during clamped hyperglycaemia (5.7 ± 1.1 to 5.2 ± 0.9 m/s, p = 0.0017). HRV, plasma noradrenalin and adrenaline remained unchanged under both clamped euglycemic and hyperglycemic conditions.

Conclusions

Empagliflozin is associated with a decline in arterial stiffness in young type 1 diabetes mellitus subjects. The underlying mechanisms may relate to pleiotropic actions of SGLT2 inhibition, including glucose lowering, antihypertensive and weight reduction effects.

Trial registration

Clinical trial registration: NCT01392560

Effects of renin-angiotensin-aldosterone system inhibitors and beta-blockers on markers of arterial stiffness

Antihypertensive agents may, even within the same class, exert variable effects on arterial stiffness variables. Nebivolol could have a better impact than atenolol on arterial stiffness, by increasing the bioavailability of endothelium-derived nitric oxide. Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) increase plasma renin activity (enhancing the production of angiotensin II via non-ACE-related pathways) whereas aliskiren does not, potentially affecting central hemodynamics differently. We compared the effects of two renin-angiotensin-aldosterone system (RAAS) inhibitors (quinapril and aliskiren) and 2 beta-blockers (atenolol and nebivolol) on arterial stiffness variables. Treatment-naïve patients (n = 72; 68.1% males; age, 47.6 ± 10.6 years) with uncomplicated stage I-II essential hypertension were randomly assigned to quinapril, aliskiren, atenolol, or nebivolol for 10 weeks. Central systolic and diastolic blood pressure (BP), central pulse pressure (PP), augmentation index (AIx), and pulse wave velocity (PWV) were measured at baseline, 2, and 10 weeks. The same measurements were performed in 20 normotensive subjects (65.0% males; age, 40.0 ± 8.9 years). Peripheral and central systolic and diastolic BP, peripheral PP, and PWV were significantly and similarly reduced by all agents. However, PWV continued to decline between the second and last visit in patients on quinapril and aliskiren but did not change in those on nebivolol or atenolol. Central PP and AIx decreased in patients on quinapril, aliskiren, and nebivolol but did not change in those taking atenolol. The decrease in central PP and AIx did not differ between patients on quinapril, aliskiren, and nebivolol. Despite similar reductions in peripheral BP, atenolol is less effective than nebivolol and RAAS inhibitors in improving central pulsatile hemodynamics. Aliskiren exerts similar effects on markers of arterial stiffness as quinapril. The clinical relevance of these differences remains to be established.

The effect of sex on endothelial function responses to clamped hyperglycemia in type 1 diabetes

Although the female sex is associated with renal protection in non-diabetic nephropathy, men and women with type 1 diabetes mellitus (T1D) have a similar risk of developing nephropathy. As hyperglycemia is associated with exaggerated effects on blood pressure and renal hyperfiltration in women versus men with T1D, we examined the influence of clamped hyperglycemia on flow mediated vasodilatation (FMD) to determine if this parameter contributes to sex-related differences in the vascular function. After a controlled diet for seven days, blood pressure, ultrasound derived FMD and circulating renin angiotensin system mediators were measured in men (n=30) and women (n=28) with T1D during clamped euglycemia and hyperglycemia. Men and women were similar in pre-study dietary parameters, age, diabetes duration, body mass index, HbA1c, renal function and proteinuria. The systolic blood pressure (SBP) was higher in men during clamped euglycemia (121±2 vs. 108±2 mm Hg, P<0.0001) and hyperglycemia (121±2 vs. 111±2 mm Hg, P<0.0001), as were the circulating levels of angiotensin II (P<0.05). SBP increased in response to hyperglycemia in women but not in men. Consistently with differences in blood pressure during clamped euglycemia, FMD was higher in women than in men (8.06±0.55 vs. 4.15±0.52%, P<0.0001). In contrast, between-group differences in FMD during clamped hyperglycemia did not reach significance owing to a decline in FMD in women, versus men, in response to clamped hyperglycemia (P=0.040 for between-group change in FMD). Clamped hyperglycemia suppresses FMD in women, but not in men, with uncomplicated T1D, which may contribute to the relative loss of protection against renal disease progression in women with T1D.

The effect of aliskiren on urinary cytokine/chemokine responses to clamped hyperglycaemia in type 1 diabetes

AIMS/HYPOTHESIS

Acute clamped hyperglycaemia activates the renin-angiotensin-aldosterone system (RAAS) and increases the urinary excretion of inflammatory cytokines/chemokines in patients with uncomplicated type 1 diabetes mellitus. Our objective was to determine whether blockade of the RAAS would blunt the effect of acute hyperglycaemia on urinary cytokine/chemokine excretion, thereby giving insights into potentially protective effects of these agents prior to the onset of clinical nephropathy.

METHODS

Blood pressure, renal haemodynamic function (inulin and para-aminohippurate clearances) and urinary cytokines/chemokines were measured after 6 h of clamped euglycaemia (4-6 mmol/l) and hyperglycaemia (9-11 mmol/l) on two consecutive days in patients with type 1 diabetes mellitus (n = 27) without overt nephropathy. Measurements were repeated after treatment with aliskiren (300 mg daily) for 30 days.

RESULTS

Before aliskiren, clamped hyperglycaemia increased filtration fraction (from 0.188 ± 0.007 to 0.206 ± 0.007, p = 0.003) and urinary fibroblast growth factor-2 (FGF2), IFN-α2 and macrophage-derived chemokine (MDC) (p < 0.005). After aliskiren, the filtration fraction response to hyperglycaemia was abolished, resulting in a lower filtration fraction after aliskiren under clamped hyperglycaemic conditions (p = 0.004), and none of the biomarkers increased in response to hyperglycaemia. Aliskiren therapy also reduced levels of urinary eotaxin, FGF2, IFN-α2, IL-2 and MDC during clamped hyperglycaemia (p < 0.005).

CONCLUSIONS/INTERPRETATION

The increased urinary excretion of inflammatory cytokines/chemokines in response to acute hyperglycaemia is blunted by RAAS blockade in humans with uncomplicated type 1 diabetes mellitus.

Dual renin-angiotensin system inhibition for prevention of renal and cardiovascular events: do the latest trials challenge existing evidence?

Circulatory and tissue renin-angiotensin systems (RAS) play a central role in cardiovascular (CV) and renal pathophysiology, making RAS inhibition a logical therapeutic approach in the prevention of CV and renal disease in patients with hypertension. The cardio- and renoprotective effects observed with angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) monotherapy, together with the availability of a direct renin inhibitor (DRI), led to the investigation of the potential benefits of dual RAS inhibition. In small studies, ARB and ACE inhibitor combinations were shown to be beneficial in patients with CV or renal disease, with improvement in surrogate markers. However, in larger outcome trials, involving combinations of ACE inhibitors, ARBs or DRIs, dual RAS inhibition did not show reduction in mortality in patients with diabetes, heart failure, coronary heart disease or after myocardial infarction, and was in fact, associated with increased harm. A recent meta-analysis of all major trials conducted over the past 22 years involving dual RAS inhibition has clearly shown that the risk-benefit ratio argues against the use of dual RAS inhibition. Hence, the recent evidence clearly advocates against the use of dual RAS inhibition, and single RAS inhibition appears to be the most suitable approach to controlling blood pressure and improving patient outcomes.

Renal hyperfiltration and systemic blood pressure in patients with uncomplicated type 1 diabetes mellitus

BACKGROUND

Patients with type 1 diabetes mellitus (DM) and renal hyperfiltration also exhibit systemic microvascular abnormalities, including endothelial dysfunction. The effect of renal hyperfiltration on systemic blood pressure (BP) is less clear. We therefore measured BP, renal hemodynamic function and circulating renin angiotensin aldosterone system (RAAS) mediators in type 1 DM patients with hyperfiltration (n = 36, DM-H, GFR≥135 ml/min/1.73 m(2)) or normofiltration (n = 40, DM-N), and 56 healthy controls (HC). Since renal hyperfiltration represents a state of intrarenal RAAS activation, we hypothesized that hyperfiltration would be associated with higher BP and elevated levels of circulating RAAS mediators.

METHODS

BP, glomerular filtration rate (GFR - inulin), effective renal plasma flow (paraaminohippurate) and circulating RAAS components were measured in DM-H, DM-N and HC during clamped euglycemia (4-6 mmol/L). Studies were repeated in DM-H and DM-N during clamped hyperglycemia (9-11 mmol/L).

RESULTS

Baseline GFR was elevated in DM-H vs. DM-N and HC (167±6 vs. 115±2 and 115±2 ml/min/1.73 m(2), p<0.0001). Baseline systolic BP (SBP, 117±2 vs. 111±2 vs. 109±1, p = 0.004) and heart rate (76±1 vs. 67±1 vs. 61±1, p<0.0001) were higher in DM-H vs. DM-N and HC. Despite higher SBP in DM-H, plasma aldosterone was lower in DM-H vs. DM-N and HC (42±5 vs. 86±14 vs. 276±41 ng/dl, p = 0.01). GFR (p<0.0001) and SBP (p<0.0001) increased during hyperglycemia in DM-N but not in DM-H.

CONCLUSIONS

DM-H was associated with higher heart rate and SBP values and an exaggerated suppression of systemic aldosterone. Future work should focus on the mechanisms that explain this paradox in diabetes of renal hyperfiltration coupled with systemic RAAS suppression.

A new anti-ageing strategy focused on prevention of arterial ageing in the middle-aged population

Ageing is a progressive process that according to available knowledge cannot be effectively reversed, slowed or stopped. Here we propose a new anti-ageing approach that may lead to the design of effective therapeutic intervention. First, we hypothesize that the "organ system" oriented anti-ageing approach represents a better anti-ageing target than the "whole body" or "cellular ageing" concepts. The arterial system is the most suitable target, as it interconnects all the organs in the body, thus influencing them all. Second, we propose that an anti-ageing approach could be more successful in early than late ageing stages; middle-aged people seem to be the most appropriate candidates. Third, we believe that instead of searching for new medication, we should rely on already established medications with beneficial effects on the arterial wall. Renin-angiotensin system inhibitors and statins fulfill these criteria and are potential cornerstones of the new approach. The fourth hypothesis is based on the concept that in the early stages of arterial ageing only slight injury is present and therefore subtherapeutic, low-dose treatment would be effective. Fifth, we hypothesize that slight initial age-related arterial wall changes are reversible and could be corrected by a short-term (one month) treatment. Sixth, we hypothesize that the effects would be present for a certain period of time even after treatment termination. The listed assumptions combined represent the basis for a new, original anti-ageing approach - a subtherapeutic low-dose combination of a renin-angiotensin system inhibitor and a statin for one month (followed by approximately 6-12 months without treatment) could delay or even reverse the arterial ageing process and consequently decrease the incidence of cardiovascular disorders.