Cabassi, Aderville

Abstract Background/Introduction Hypertension (HTN) and metabolic syndrome (MetS) are both leading risk factors for major cardiovascular diseases, which frequently coexist as a complicated cardiometabolic disorder. The cardiac hormone atrial natriuretic peptide (ANP) plays a key role in both blood pressure and metabolic regulation through activation of the guanylyl cyclase-A receptor (GC-A) and the second messenger 3’,5’ cyclic guanosine monophosphate (cGMP). Indeed, ANP decreases blood pressure, induces lipolysis by increasing plasma levels of non-esterified fatty acids (NEFA) and improves insulin-sensitivity. MANP is a new Mayo Clinic designed natriuretic peptide consisting of the native ANP with a 12-amino-acid C-terminus extension and its biological actions are mediated by the GC-A/cGMP pathway. MANP is less susceptible to neprilysin degradation and exert more sustained cGMP dependent biological actions than ANP. Purpose In a proof-of-principle human study, for the first time we aimed to determine the cardiovascular and metabolic properties of MANP, a novel ANP analog, in the clinical setting of HTN with MetS. Methods We conducted a double-blind, placebo-controlled trial in 22 patients (17 receiving MANP) with HTN and MetS involving single subcutaneous injection of MANP (2.5 µg/kg) or placebo (NCT03781739). Blood pressure (BP) and circulating cGMP were monitored for 24 hours post treatment. Circulating metabolic parameters including insulin, glucose, non-esterified fatty acids (NEFA) and insulin resistance (HOMA-IR) and insulin sensitivity (HOMA-IS) indexes were assessed for the first 4 hours post treatment. Results Compared to baseline, MANP increased plasma cGMP at 30 minutes (delta: 4.8 ± 2.0 pmol/mL, P = 0.02) and 1 hour (delta: 2.9 ± 1.3 pmol/mL, P = 0.03) post injection. At 6 hours, systolic BP decreased by 5.7 ± 2.9 mmHg (P = 0.06) in the MANP group, whereas no reduction in BP was observed in placebo group. Among the 17 subjects receiving MANP, lower baseline cGMP levels were associated with greater mean reductions in systolic BP (ρ = 0.66, P = 0.005). After MANP injection, glucose levels decreased at 2 (delta: -4.7 ± 2.1 mg/mL, P = 0.04) and 4 hours (delta: -13.1 ± 3.9 mg/mL, P = 0.003) compared to baseline while insulin levels remained stable. During the first 4 hours post injection, we also observed a trend of increase in insulin sensitivity index (HOMA2-IS) and decrease in insulin resistance index (HOMA2-IR) with MANP, both were opposite to the trends in placebo. At 1 hour post MANP administration, NEFA increased by 108.2 ± 37.4 µM compared to baseline (P = 0.01). Conclusion(s) Our findings support the favorable cardiovascular and metabolic actions of MANP as a potential therapeutic strategy for HTN with MetS.

Introduction: Atrial natriuretic peptide (ANP) plays an important role in blood pressure (BP) regulation via the second messenger cGMP. ANP also induces lipolysis by increasing plasma levels of non-esterified fatty acids (NEFA). MANP is a new Mayo Clinic designed ANP analog consisting of the native ANP with a novel 12-amino-acid C-terminus extension. In experimental models, MANP is more potent than ANP in reducing BP and inducing natriuresis. These actions are mediated by the activation of the pGC-A receptor and generation of cGMP. To date, the BP pressure lowering, cGMP generating and lipolytic actions of MANP remain unexplored along with its safety and tolerability in subjects with hypertension (HTN) associated with metabolic disease. Hypothesis: In subjects with HTN, obesity and metabolic syndrome (MS), MANP administration is safe, well tolerated, activates cGMP and exerts BP lowering and lipolytic properties. Methods: Double-blind, placebo-control clinical trial in 22 subjects (17 receiving MANP) with HTN, obesity and MS involving a single subcutaneous (SQ) injection of MANP (2.5 μg/Kg) or placebo. Subjects were monitored and cardiovascular, cGMP and metabolic parameters were collected during 24 hours after the injection. Results: In all subjects, MANP was safe and well-tolerated with no serious adverse side effects. MANP increased mean cGMP plasma levels after 30 minutes (delta: 4.8 ± 2.0 pmol/mL, p=0.02) and 1 hour (delta: 2.9 ±1.3 pmol/mL, p=0.03) when compared to baseline. Six hours after MANP injection systolic BP decreased by 5.7 ± 2.9 mmHg (p=0.06) whereas subjects receiving placebo had no decrease in blood pressure values compared to baseline. During fasting period, one hour after the administration of MANP, NEFA plasma levels increased by 108.2 ± 37.4 μM (p=0.01). Conclusions: In subjects with HTN, obesity and MS, SQ MANP is safe, well tolerated and activates the pGC-A receptor as measured by a significant increase in the second messenger cGMP. Subjects receiving MANP showed a borderline significant decrease in systolic BP and a significant increase in NEFA circulating levels supporting anti-hypertensive and lipolytic properties. Our findings support MANP as a potential novel therapy for HTN associated with metabolic disease.

Atrial natriuretic peptide (ANP) is a cardiac hormone with pleiotropic cardiovascular and metabolic properties including vasodilation, natriuresis and suppression of the renin-angiotensin-aldosterone system. Moreover, ANP induces lipolysis, lipid oxidation, adipocyte browning and ameliorates insulin sensitivity. Studies on ANP genetic variants revealed that subjects with higher ANP plasma levels have lower cardio-metabolic risk. In vivo and in humans, augmenting the ANP pathway has been shown to exert cardiovascular therapeutic actions while ameliorating the metabolic profile. MANP is a novel designer ANP-based peptide with greater and more sustained biological actions than ANP in animal models. Recent studies also demonstrated that MANP lowers blood pressure and inhibits aldosterone in hypertensive subjects whereas cardiometabolic properties of MANP are currently tested in an on-going clinical study in hypertension and metabolic syndrome. Evidence from in vitro, in vivo and in human studies support the concept that ANP and related pathway represent an optimal target for a comprehensive approach to cardiometabolic disease.