Inhibiting the renin-angiotensin system with ACE Inhibitors or ARBs after MI

Left atrial strain quantified after myocardial infarction is associated with early left ventricular remodeling

BACKGROUND

Left ventricular remodeling (LVR) is common and associated with adverse outcome after ST-elevation myocardial infarction (STEMI). We aimed to investigate the association between left atrial (LA) mechanical function using speckle tracking imaging and early LVR at follow-up in STEMI patients.

METHODS

Baseline 3D thoracic echocardiograms were performed within 48 h following admission and at a median follow-up of 7 months after STEMI. A > 20% increase in the left ventricular (LV) end-diastolic volume compared to baseline at follow-up was defined as LVR. LA global longitudinal strain was evaluated for the reservoir, conduit, and contraction (LASct) phases.

RESULTS

A total of 121 patients without clinical heart failure (HF) were prospectively included, between June 2015 and October 2018 (age 58.3 ± 12.5 years, male 98 (81%)). Baseline and follow-up LV ejection fraction (LVEF) were 46.8% [41.0, 52.9] and 52.1% [45.8, 57.0] respectively (p < .001). Compared to other patients, those with LVR had significantly lower values of LASct at baseline (-7.4% [-10.1, -6.5] vs. -9.9% [-12.8, -8.1], p < .01), both on univariate and baseline LV volumes-adjusted analyses. Baseline LA strain for reservoir and conduit phases were not associated with significant LVR at follow-up. Intra- and interobserver analysis showed good reproducibility of LA strain.

CONCLUSIONS

Baseline LASct may help identifying patients without HF after STEMI who are at higher risk of further early LVR and subsequent HF and who may benefit from more intensive management.

Serum neprilysin levels are associated with myocardial stunning after ST-elevation myocardial infarction

Background

Left ventricular remodeling following ST-elevation myocardial infarction (STEMI) is associated with poor outcome, including heart failure (HF). Neprilysin inhibition leads to improved outcome in patients with altered left ventricular ejection fraction (LVEF).

Methods

We aimed to assess the association between serum levels of neprilysin and left ventricular (LV) volumes, function and remodeling in STEMI patients with successful myocardial reperfusion and no clinical sign of HF. Sixty-eight patients were admitted for STEMI and had both plasma neprilysin measurement at baseline and 3D transthoracic echocardiogram at baseline and after a median follow-up of 7 months. We compared 3 groups: a group with a low-level of plasma neprilysin (< 125 pg/mL, i.e. the lower limit of detection of the assay) and the two other groups were defined as being below or above the median value of the remaining samples.

Results

Median age was 58.5 ± 12.8 years and 56 (82.4%) were men. Median LVEF was 45.0 ± 8.5%. Baseline characteristics were comparable between groups (low-level of neprilysin group [≤125 pg/mL, n = 38], medium-level of neprilysin group [126–450 pg/mL, n = 15] and a high-level group [> 450 pg/mL, n = 15]). At baseline there was a non-significant trend towards lower end-diastolic volume (p = 0.07) but significantly lower LVEF in the high neprilysin group (46.4 ± 8.3%, 47.1 ± 8.1% and 39.1 ± 6.9%, p < 0.01). At follow-up, the magnitude of LVEF increase was significantly more important in the high neprilysin group compared to the other groups (p = 0.022 for relative change in LVEF and 6.6 ± 7.3%, 3.6 ± 9.0% and 11.3 ± 8.4%, p = 0.031 for absolute change in LVEF) resulting in similar LVEF levels at follow-up between all groups (53.0 ± 8.9%, 50.6 ± 9.7% and 50.4 ± 9.9%, p = 0.55).

Conclusions

Initial high neprilysin levels may identify patients with stunned myocardium early after STEMI, with a recovery of contractility leading to improved LVEF at follow-up. Future studies will have to assess the role of neprilysin in the setting of STEMI and the potential benefit of its blockade.

Relationship of angiotensin I-converting enzyme (ACE) and bradykinin B2 receptor (BDKRB2) polymorphism with diabetic nephropathy

PURPOSE

To determine whether ACE² I/D and BDKRB2³ +9/-9 polymorphism causatively affect diabetic nephropathy progression RESULTS: STZ-induced metabolic disorder, as well as inflammatory responses, was significantly aggravated in ACE II-B2R⁴+9bp, ACE DD-B2R+9bp, or ACE DD-B2R-9bp diabetic mice but not ACE II-B2R-9bp, indicating the genetic susceptibility of ACE DD or B2R+9bp to diabetic nephropathy. Furthermore, ACE II-B2R+9bp, ACE DD-B2R+9bp, or ACE DD-B2R-9bp rather than ACE II-B2R-9bp, worsened renal performance and enhanced pathological alterations induced by STZ. Markedly elevated monocyte chemoattractant protein-1(MCP-1), podocin, osteopontin (OPN), transforming growth factor-β1 (TGF-β1), and reduced nephrin, podocin were also detected both in diabetic mice and podocytes under hyperglycemic conditions in response to ACE II-B2R+9bp, ACE DD-B2R+9bp, or ACE DD-B2R-9bp, versus ACE II-B2R-9bp. In addition, high glucose-induced mitochondrial oxidative stress and cell apoptosis were observably increased in response to ACE II-B2R+9bp, ACE DD-B2R+9bp, or ACE DD-B2R-9bp but not ACE II-B2R-9bp.

CONCLUSIONS

We provide first evidence indicating the causation between ACE DD or B2R+9bp genotype and the increased risk for diabetic nephropathy, broadening our horizon about the role of genetic modulators in this disease.

ACE inhibitors - angiotensin II receptor antagonists: A useful combination therapy for ischemic heart disease

Morbidity and mortality from cardiovascular diseases are still high, even with the use of the best available therapies. There is mounting evidence that excessive renin-angiotensin system activation triggers much of the damaging and progressive nature of cardiovascular and kidney diseases through expression of angiotensin II. Moreover, angiotensin II play a major role in the development of end organ damage through a variety of inflammatory mechanisms. Today, angiotensins-converting enzyme (ACE) inhibitors and angiotensin II receptor antagonists have clearly demonstrated their efficacy in preventing target organ damage and in reducing cardiovascular morbidity and mortality in ischemic heart disease (IHD). Moreover, the development of angiotensin II receptor antagonists has enabled a large gain in tolerability and safety. Several clinical trials have firmly established that these drugs act on the renin–angiotensin system, reducing the incidence of coronary events with monotherapy and combination therapy. In this review we summarize the role mono- and combined therapy of ACE inhibitors and angiotensin II receptor antagonists play in ischemic heart disease. In this respect the review will improve ideas for developing new formulations with combinations of these drugs in the future.

The role of the renin-angiotensin-aldosterone system in cardiovascular progenitor cell function

Intervention in the RAAS (renin-angiotensin-aldosterone system) is one of the leading pharmacotherapeutic strategies, among others, used for the treatment of cardiovascular disease to improve the prognosis after myocardial infarction and to reduce hypertension. Recently, regenerative progenitor cell therapy has emerged as a possible alternative for pharmacotherapy in patients after myocardial infarction or ischaemic events elsewhere, e.g. in the limbs. Angiogenic cell therapy to restore the vascular bed in ischaemic tissues is currently being tested in a multitude of clinical studies. This has prompted researchers to investigate the effect of modulation of the RAAS on progenitor cells. Furthermore, the relationship between hypertension and endothelial progenitor cell function is being studied. Pharmacotherapy by means of angiotensin II type 1 receptor antagonists or angiotensin-converting enzyme inhibitors has varying effects on progenitor cell levels and function. These controversial effects may be explained by involvement of multiple mediators, e.g. angiotensin II and angiotensin-(1-7), that have differential effects on mesenchymal stem cells, haematopoietic progenitor cells and endothelial progenitor cells. Importantly, angiotensin II can either stimulate endothelial progenitor cells by improvement of vascular endothelial growth factor signalling, or invoke excessive production of reactive oxygen species causing premature senescence of these cells. On the other hand, angiotensin-(1-7) stimulates haematopoietic cells and possibly also endothelial progenitor cells. Furthermore, aldosterone, bradykinin and Ac-SDKP (N-acetyl-Ser-Asp-Lys-Pro) may also affect progenitor cell populations. Alternatively, the variability in effects of angiotensin II type 1 receptor and angiotensin-converting enzyme inhibition on cardiovascular progenitor cells might reflect differences between the various models or diseases with respect to circulating and local tissue RAAS activation. In the present review we discuss what is currently known with respect to the role of the RAAS in the regulation of cardiovascular progenitor cells.